Refactor entity tracking and meta handling

This essentially merges the two approaches to the metadata handling from ViaVersion and ViaBackwards and improves on both designs.

ViaVersion did not track every single entity, but only those needed (at least in theory) and can work with untracked entities' metadata. It had a very simple method overridden by metadata rewriter implementations, directly operating on the full metadata list and manually handling meta index changes as well as item/block/particle id changes.

ViaBackwards on the other hand had to track *every single* entity and threw warnings otherwise - while less prone to errors due to giving obvious warnings in the console, it unnecessarily tracks a lot of entities, and those warnings also annoys users when encountering virtual entity plugins (operating asynchronously and sending update packets while already untracked or not yet tracked). Dedicated MetaHandlers made id changes and filtering a lot easier to read and write. However, the actual metadata list handling and its distribution to handlers was not very well implemented and required a lot of list copying and creation as well as exception throws to cancel individual metadata entries.

This version has MetaFilters built with a Builder containing multiple helper functions, and the entity tracking is properly given its own map, hashed by a Protocol's class, to be easily and generically accessible from anywhere with only a Protocol class from the UserConnection, along with more optimized metadata list iteration. The entity tracking is largely unchanged, keeping ViaVersion's approach to not having to track *all* entities (and being able to handle null types in meta handlers).

All of this is by no means absolutely perfect, but is much less prone to errors than both previous systems and takes a lot less effort to actually write. A last possible change would be to use a primitive int to object map that is built to be concurrency save for the EntityTracker, tho that would have to be chosen carefully.

api/src/main/java/com/viaversion/viaversion/api/connection/UserConnection.java

@@ -23,6 +23,8 @@
 package com.viaversion.viaversion.api.connection;
 
 import com.viaversion.viaversion.api.configuration.ViaVersionConfig;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.protocol.packet.PacketTracker;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.exception.CancelException;
@@ -32,6 +34,7 @@ import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
+import java.util.Collection;
 import java.util.Map;
 import java.util.UUID;
 import java.util.function.Function;
@@ -62,6 +65,30 @@ public interface UserConnection {
      */
     void put(StoredObject object);
 
+    /**
+     * Returns a collection of entity trackers currently registered.
+     *
+     * @return collection of entity trackers currently registered
+     */
+    Collection<EntityTracker> getEntityTrackers();
+
+    /**
+     * Returns the entity tracker by the given protocol class if present.
+     *
+     * @param protocolClass protocol class
+     * @param <T>           entity tracker type
+     * @return entity tracker if present
+     */
+    @Nullable <T extends EntityTracker> T getEntityTracker(Class<? extends Protocol> protocolClass);
+
+    /**
+     * Adds an entity tracker to the user connection.
+     *
+     * @param protocolClass protocol class
+     * @param tracker       entity tracker
+     */
+    void addEntityTracker(Class<? extends Protocol> protocolClass, EntityTracker tracker);
+
     /**
      * Clear all the stored objects.
      * Used for bungee when switching servers.

api/src/main/java/com/viaversion/viaversion/api/data/entity/ClientEntityIdChangeListener.java

@@ -20,9 +20,9 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-package com.viaversion.viaversion.api.platform;
+package com.viaversion.viaversion.api.data.entity;
 
-public interface ExternalJoinGameListener {
+public interface ClientEntityIdChangeListener {
 
-    void onExternalJoinGame(int playerEntityId);
+    void setClientEntityId(int entityId);
 }

api/src/main/java/com/viaversion/viaversion/api/data/entity/EntityTracker.java

@@ -0,0 +1,129 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2021 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.data.entity;
+
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public interface EntityTracker extends ClientEntityIdChangeListener {
+
+    /**
+     * User connection the tracker belongs to.
+     *
+     * @return user connection
+     */
+    UserConnection user();
+
+    /**
+     * Tracks an entity.
+     *
+     * @param id   entity id
+     * @param type entity type
+     */
+    void addEntity(int id, EntityType type);
+
+    /**
+     * Returns whether the entity is currently tracked.
+     *
+     * @param id entity id
+     * @return whether the entity is tracked
+     */
+    boolean hasEntity(int id);
+
+    /**
+     * Entity type of the entity if tracked.
+     * This returning null does not necessarily mean no entity by the id exists.
+     *
+     * @param id entity id
+     * @return entity type of the entity if tracked
+     */
+    @Nullable EntityType entityType(int id);
+
+    /**
+     * Untracks an entity.
+     *
+     * @param id entity id
+     */
+    void removeEntity(int id);
+
+    /**
+     * Returns the stored entity data if an entity with the id is tracked, else null.
+     * If no data has been initialized yet, it will be done and returned by this method.
+     *
+     * @param id entity id
+     * @return stored entity data if an entity with the id is tracked, else null
+     */
+    @Nullable StoredEntityData entityData(int id);
+
+    /**
+     * Returns stored entity data if it has previously been initialized by {@link #entityData(int)}, else null.
+     *
+     * @param id entity id
+     * @return stored entity data if it has previously been initialized by {@link #entityData(int)}
+     */
+    @Nullable StoredEntityData entityDataIfPresent(int id);
+
+    /**
+     * Returns the client entity id or -1 if unset.
+     *
+     * @return client entity id or -1 if unset
+     */
+    int clientEntityId();
+
+    /**
+     * Sets the client entity id.
+     *
+     * @param clientEntityId client entity id
+     */
+    void setClientEntityId(int clientEntityId);
+
+    /**
+     * Returns the current world section height.
+     * Always 16 for sub 1.17 worlds.
+     *
+     * @return current world section height
+     */
+    int currentWorldSectionHeight();
+
+    /**
+     * Sets the current world section height.
+     *
+     * @param currentWorldSectionHeight world section height
+     */
+    void setCurrentWorldSectionHeight(int currentWorldSectionHeight);
+
+    /**
+     * Returns the minimum y of the current player world.
+     *
+     * @return minimum y of the current world
+     */
+    int currentMinY();
+
+    /**
+     * Sets the minimum y of the current player world.
+     *
+     * @param currentMinY minimum y of the current world
+     */
+    void setCurrentMinY(int currentMinY);
+}

api/src/main/java/com/viaversion/viaversion/api/data/entity/StoredEntityData.java

@@ -0,0 +1,60 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2021 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.data.entity;
+
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public interface StoredEntityData {
+
+    /**
+     * Returns the entity type of the stored entity.
+     *
+     * @return entity type
+     */
+    EntityType type();
+
+    /**
+     * Checks if the storage contains an object of the given type.
+     *
+     * @param objectClass object class to check
+     * @return whether an object of the given type is in the storage
+     */
+    boolean has(Class<?> objectClass);
+
+    /**
+     * Returns an object from the storage if present.
+     *
+     * @param objectClass class of the object to get
+     * @param <T>         object type
+     * @return object if present
+     */
+    @Nullable <T> T get(Class<T> objectClass);
+
+    /**
+     * Stores an object based on its class.
+     *
+     * @param object object to store
+     */
+    void put(Object object);
+}

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/MetaType.java

@@ -31,12 +31,12 @@ public interface MetaType {
      *
      * @return Type instance
      */
-    Type getType();
+    Type type();
 
     /**
      * Get type id from the specific MetaDataType
      *
      * @return Type id as an integer
      */
-    int getTypeID();
+    int typeId();
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/Metadata.java

@@ -24,7 +24,7 @@ package com.viaversion.viaversion.api.minecraft.metadata;
 
 import java.util.Objects;
 
-public class Metadata {
+public final class Metadata {
     private int id;
     private MetaType metaType;
     private Object value;
@@ -35,7 +35,7 @@ public class Metadata {
         this.value = value;
     }
 
-    public int getId() {
+    public int id() {
         return id;
     }
 
@@ -43,7 +43,7 @@ public class Metadata {
         this.id = id;
     }
 
-    public MetaType getMetaType() {
+    public MetaType metaType() {
         return metaType;
     }
 
@@ -51,12 +51,12 @@ public class Metadata {
         this.metaType = metaType;
     }
 
-    public Object getValue() {
+    public <T> T value() {
-        return value;
+        return (T) value;
     }
 
-    public <T> T getCastedValue() {
+    public Object getValue() {
-        return (T) value;
+        return value;
     }
 
     public void setValue(Object value) {
@@ -70,7 +70,7 @@ public class Metadata {
 
         Metadata metadata = (Metadata) o;
         if (id != metadata.id) return false;
-        if (!Objects.equals(metaType, metadata.metaType)) return false;
+        if (metaType != metaType) return false;
         return Objects.equals(value, metadata.value);
     }
 

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/types/MetaType1_12.java

@@ -55,12 +55,12 @@ public enum MetaType1_12 implements MetaType {
     }
 
     @Override
-    public int getTypeID() {
+    public int typeId() {
         return typeID;
     }
 
     @Override
-    public Type getType() {
+    public Type type() {
         return type;
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/types/MetaType1_13.java

@@ -58,12 +58,12 @@ public enum MetaType1_13 implements MetaType {
     }
 
     @Override
-    public int getTypeID() {
+    public int typeId() {
         return typeID;
     }
 
     @Override
-    public Type getType() {
+    public Type type() {
         return type;
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/types/MetaType1_13_2.java

@@ -58,12 +58,12 @@ public enum MetaType1_13_2 implements MetaType {
     }
 
     @Override
-    public int getTypeID() {
+    public int typeId() {
         return typeID;
     }
 
     @Override
-    public Type getType() {
+    public Type type() {
         return type;
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/types/MetaType1_14.java

@@ -61,12 +61,12 @@ public enum MetaType1_14 implements MetaType {
     }
 
     @Override
-    public int getTypeID() {
+    public int typeId() {
         return typeID;
     }
 
     @Override
-    public Type getType() {
+    public Type type() {
         return type;
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/types/MetaType1_17.java

@@ -61,12 +61,12 @@ public enum MetaType1_17 implements MetaType {
     }
 
     @Override
-    public int getTypeID() {
+    public int typeId() {
         return typeID;
     }
 
     @Override
-    public Type getType() {
+    public Type type() {
         return type;
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/types/MetaType1_8.java

@@ -49,12 +49,12 @@ public enum MetaType1_8 implements MetaType {
     }
 
     @Override
-    public int getTypeID() {
+    public int typeId() {
         return typeID;
     }
 
     @Override
-    public Type getType() {
+    public Type type() {
         return type;
     }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/metadata/types/MetaType1_9.java

@@ -54,12 +54,12 @@ public enum MetaType1_9 implements MetaType {
     }
 
     @Override
-    public int getTypeID() {
+    public int typeId() {
         return typeID;
     }
 
     @Override
-    public Type getType() {
+    public Type type() {
         return type;
     }
 }

api/src/main/java/com/viaversion/viaversion/api/protocol/AbstractProtocol.java

@@ -24,6 +24,8 @@ package com.viaversion.viaversion.api.protocol;
 
 import com.google.common.base.Preconditions;
 import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
 import com.viaversion.viaversion.api.protocol.packet.ClientboundPacketType;
 import com.viaversion.viaversion.api.protocol.packet.Direction;
 import com.viaversion.viaversion.api.protocol.packet.PacketType;
@@ -144,6 +146,10 @@ public abstract class AbstractProtocol<C1 extends ClientboundPacketType, C2 exte
     protected void onMappingDataLoaded() {
     }
 
+    public void addEntityTracker(UserConnection connection, EntityTracker tracker) {
+        connection.addEntityTracker(this.getClass(), tracker);
+    }
+
     @Override
     public void registerServerbound(State state, int oldPacketID, int newPacketID, PacketRemapper packetRemapper, boolean override) {
         ProtocolPacket protocolPacket = new ProtocolPacket(state, oldPacketID, newPacketID, packetRemapper);

api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/ModernMetaType.java

@@ -32,7 +32,7 @@ public abstract class ModernMetaType extends MetaTypeTemplate {
         final short index = buffer.readUnsignedByte();
         if (index == 0xff) return null; // End of metadata
         final MetaType type = this.getType(buffer.readByte());
-        return new Metadata(index, type, type.getType().read(buffer));
+        return new Metadata(index, type, type.type().read(buffer));
     }
 
     protected abstract MetaType getType(final int index);
@@ -42,10 +42,10 @@ public abstract class ModernMetaType extends MetaTypeTemplate {
         if (object == null) {
             buffer.writeByte(0xff);
         } else {
-            buffer.writeByte(object.getId());
+            buffer.writeByte(object.id());
-            final MetaType type = object.getMetaType();
+            final MetaType type = object.metaType();
-            buffer.writeByte(type.getTypeID());
+            buffer.writeByte(type.typeId());
-            type.getType().write(buffer, object.getValue());
+            type.type().write(buffer, object.getValue());
         }
     }
 }

api/src/main/java/com/viaversion/viaversion/api/type/types/version/Metadata1_8Type.java

@@ -37,13 +37,13 @@ public class Metadata1_8Type extends MetaTypeTemplate {
         int typeID = (item & 0xE0) >> 5;
         MetaType1_8 type = MetaType1_8.byId(typeID);
         int id = item & 0x1F;
-        return new Metadata(id, type, type.getType().read(buffer));
+        return new Metadata(id, type, type.type().read(buffer));
     }
 
     @Override
     public void write(ByteBuf buffer, Metadata meta) throws Exception {
-        byte item = (byte) (meta.getMetaType().getTypeID() << 5 | meta.getId() & 0x1F);
+        byte item = (byte) (meta.metaType().typeId() << 5 | meta.id() & 0x1F);
         buffer.writeByte(item);
-        meta.getMetaType().getType().write(buffer, meta.getValue());
+        meta.metaType().type().write(buffer, meta.getValue());
     }
 }

bukkit-legacy/src/main/java/com/viaversion/viaversion/bukkit/listeners/protocol1_9to1_8/BlockListener.java

@@ -17,15 +17,15 @@
  */
 package com.viaversion.viaversion.bukkit.listeners.protocol1_9to1_8;
 
+import com.viaversion.viaversion.api.minecraft.Position;
+import com.viaversion.viaversion.bukkit.listeners.ViaBukkitListener;
+import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
+import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.EntityTracker1_9;
 import org.bukkit.block.Block;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.block.BlockPlaceEvent;
 import org.bukkit.plugin.Plugin;
-import com.viaversion.viaversion.api.minecraft.Position;
-import com.viaversion.viaversion.bukkit.listeners.ViaBukkitListener;
-import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
-import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.EntityTracker1_9;
 
 public class BlockListener extends ViaBukkitListener {
 
@@ -37,9 +37,8 @@ public class BlockListener extends ViaBukkitListener {
     public void placeBlock(BlockPlaceEvent e) {
         if (isOnPipe(e.getPlayer())) {
             Block b = e.getBlockPlaced();
-            getUserConnection(e.getPlayer())
+            EntityTracker1_9 tracker = getUserConnection(e.getPlayer()).getEntityTracker(Protocol1_9To1_8.class);
-                    .get(EntityTracker1_9.class)
+            tracker.addBlockInteraction(new Position(b.getX(), (short) b.getY(), b.getZ()));
-                    .addBlockInteraction(new Position(b.getX(), (short) b.getY(), b.getZ()));
         }
     }
 }

bungee/src/main/java/com/viaversion/viaversion/bungee/handlers/BungeeServerHandler.java

@@ -21,10 +21,11 @@ import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.ProtocolInfo;
 import com.viaversion.viaversion.api.connection.StoredObject;
 import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.platform.ExternalJoinGameListener;
+import com.viaversion.viaversion.api.data.entity.ClientEntityIdChangeListener;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.protocol.ProtocolPathEntry;
 import com.viaversion.viaversion.api.protocol.ProtocolPipeline;
-import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.protocol.version.ProtocolVersion;
 import com.viaversion.viaversion.api.type.Type;
@@ -125,9 +126,15 @@ public class BungeeServerHandler implements Listener {
         } catch (Exception ex) {
             return; // Ignored
         }
-        for (StoredObject storedObject : userConnection.getStoredObjects().values()) {
+
-            if (storedObject instanceof ExternalJoinGameListener) {
+        for (EntityTracker tracker : userConnection.getEntityTrackers()) {
-                ((ExternalJoinGameListener) storedObject).onExternalJoinGame(playerId);
+            tracker.setClientEntityId(playerId);
+        }
+
+        // For ViaRewind
+        for (StoredObject object : userConnection.getStoredObjects().values()) {
+            if (object instanceof ClientEntityIdChangeListener) {
+                ((ClientEntityIdChangeListener) object).setClientEntityId(playerId);
             }
         }
     }
@@ -143,7 +150,7 @@ public class BungeeServerHandler implements Listener {
             if (e.getServer() != null) {
                 if (!e.getServer().getInfo().getName().equals(storage.getCurrentServer())) {
                     // Clear auto-team
-                    EntityTracker1_9 oldEntityTracker = user.get(EntityTracker1_9.class);
+                    EntityTracker1_9 oldEntityTracker = user.getEntityTracker(Protocol1_9To1_8.class);
                     if (oldEntityTracker != null) {
                         if (oldEntityTracker.isAutoTeam() && oldEntityTracker.isTeamExists()) {
                             oldEntityTracker.sendTeamPacket(false, true);
@@ -239,7 +246,7 @@ public class BungeeServerHandler implements Listener {
                         protocol.init(user);
                     }
 
-                    EntityTracker1_9 newTracker = user.get(EntityTracker1_9.class);
+                    EntityTracker1_9 newTracker = user.getEntityTracker(Protocol1_9To1_8.class);
                     if (newTracker != null) {
                         if (Via.getConfig().isAutoTeam()) {
                             String currentTeam = null;

bungee/src/main/java/com/viaversion/viaversion/bungee/listeners/ElytraPatch.java

@@ -45,7 +45,8 @@ public class ElytraPatch implements Listener {
 
         try {
             if (user.getProtocolInfo().getPipeline().contains(Protocol1_9To1_8.class)) {
-                int entityId = user.get(EntityTracker1_9.class).getProvidedEntityId();
+                EntityTracker1_9 tracker = user.getEntityTracker(Protocol1_9To1_8.class);
+                int entityId = tracker.getProvidedEntityId();
 
                 PacketWrapper wrapper = PacketWrapper.create(0x39, null, user);
 

common/src/main/java/com/viaversion/viaversion/connection/UserConnectionImpl.java

@@ -22,6 +22,8 @@ import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.ProtocolInfo;
 import com.viaversion.viaversion.api.connection.StoredObject;
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
+import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.protocol.packet.Direction;
 import com.viaversion.viaversion.api.protocol.packet.PacketTracker;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
@@ -35,7 +37,9 @@ import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandlerContext;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
+import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 import java.util.UUID;
@@ -48,6 +52,7 @@ public class UserConnectionImpl implements UserConnection {
     private static final AtomicLong IDS = new AtomicLong();
     private final long id = IDS.incrementAndGet();
     private final Map<Class<?>, StoredObject> storedObjects = new ConcurrentHashMap<>();
+    private final Map<Class<? extends Protocol>, EntityTracker> entityTrackers = new HashMap<>();
     private final PacketTracker packetTracker = new PacketTracker(this);
     private final Set<UUID> passthroughTokens = Collections.newSetFromMap(CacheBuilder.newBuilder()
             .expireAfterWrite(10, TimeUnit.SECONDS)
@@ -91,6 +96,21 @@ public class UserConnectionImpl implements UserConnection {
         storedObjects.put(object.getClass(), object);
     }
 
+    @Override
+    public Collection<EntityTracker> getEntityTrackers() {
+        return entityTrackers.values();
+    }
+
+    @Override
+    public @Nullable <T extends EntityTracker> T getEntityTracker(Class<? extends Protocol> protocolClass) {
+        return (T) entityTrackers.get(protocolClass);
+    }
+
+    @Override
+    public void addEntityTracker(Class<? extends Protocol> protocolClass, EntityTracker tracker) {
+        entityTrackers.put(protocolClass, tracker);
+    }
+
     @Override
     public void clearStoredObjects() {
         storedObjects.clear();

common/src/main/java/com/viaversion/viaversion/data/EntityTracker.java

@@ -1,68 +0,0 @@
-/*
- * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
- * Copyright (C) 2016-2021 ViaVersion and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package com.viaversion.viaversion.data;
-
-import com.viaversion.viaversion.api.connection.StoredObject;
-import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.minecraft.entities.EntityType;
-import com.viaversion.viaversion.api.platform.ExternalJoinGameListener;
-import org.checkerframework.checker.nullness.qual.Nullable;
-
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-
-public abstract class EntityTracker extends StoredObject implements ExternalJoinGameListener {
-    private final Map<Integer, EntityType> clientEntityTypes = new ConcurrentHashMap<>();
-    private final EntityType playerType;
-    private int clientEntityId;
-
-    protected EntityTracker(UserConnection user, EntityType playerType) {
-        super(user);
-        this.playerType = playerType;
-    }
-
-    public void removeEntity(int entityId) {
-        clientEntityTypes.remove(entityId);
-    }
-
-    public void addEntity(int entityId, EntityType type) {
-        clientEntityTypes.put(entityId, type);
-    }
-
-    public boolean hasEntity(int entityId) {
-        return clientEntityTypes.containsKey(entityId);
-    }
-
-    public @Nullable EntityType getEntity(int entityId) {
-        return clientEntityTypes.get(entityId);
-    }
-
-    @Override
-    public void onExternalJoinGame(int playerEntityId) {
-        clientEntityId = playerEntityId;
-        clientEntityTypes.put(playerEntityId, playerType);
-    }
-
-    public int getClientEntityId() {
-        return clientEntityId;
-    }
-
-    public void setClientEntityId(int clientEntityId) {
-        this.clientEntityId = clientEntityId;
-    }
-}

common/src/main/java/com/viaversion/viaversion/data/entity/EntityTrackerBase.java

@@ -0,0 +1,133 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2021 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.viaversion.viaversion.data.entity;
+
+import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
+import com.viaversion.viaversion.api.data.entity.StoredEntityData;
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class EntityTrackerBase implements EntityTracker {
+    private final Map<Integer, EntityType> entityTypes = new ConcurrentHashMap<>();
+    private final Map<Integer, StoredEntityData> entityData;
+    private final UserConnection connection;
+    private final EntityType playerType;
+    private int clientEntityId = -1;
+    private int currentWorldSectionHeight = 16;
+    private int currentMinY;
+
+    public EntityTrackerBase(UserConnection connection, @Nullable EntityType playerType) {
+        this(connection, playerType, false);
+    }
+
+    public EntityTrackerBase(UserConnection connection, @Nullable EntityType playerType, boolean storesEntityData) {
+        this.connection = connection;
+        this.playerType = playerType;
+        this.entityData = storesEntityData ? new ConcurrentHashMap<>() : null;
+    }
+
+    @Override
+    public UserConnection user() {
+        return connection;
+    }
+
+    @Override
+    public void addEntity(int id, EntityType type) {
+        entityTypes.put(id, type);
+    }
+
+    @Override
+    public boolean hasEntity(int id) {
+        return entityTypes.containsKey(id);
+    }
+
+    @Override
+    public @Nullable EntityType entityType(int id) {
+        return entityTypes.get(id);
+    }
+
+    @Override
+    public StoredEntityData entityData(int id) {
+        EntityType type = entityType(id);
+        return entityData.computeIfAbsent(id, s -> new StoredEntityImpl(type));
+    }
+
+    @Override
+    public @Nullable StoredEntityData entityDataIfPresent(int id) {
+        return entityData.get(id);
+    }
+
+    @Override
+    public void removeEntity(int id) {
+        entityTypes.remove(id);
+        if (entityData != null) {
+            entityData.remove(id);
+        }
+    }
+
+    @Override
+    public int clientEntityId() {
+        return clientEntityId;
+    }
+
+    @Override
+    public void setClientEntityId(int clientEntityId) {
+        Preconditions.checkNotNull(playerType);
+        entityTypes.put(clientEntityId, playerType);
+        if (entityData != null) {
+            StoredEntityData data = entityData.remove(this.clientEntityId);
+            if (data != null) {
+                entityData.put(clientEntityId, data);
+            }
+        }
+
+        this.clientEntityId = clientEntityId;
+    }
+
+    /**
+     * @return amount of chunk sections of the current world (block height / 16)
+     */
+    @Override
+    public int currentWorldSectionHeight() {
+        return currentWorldSectionHeight;
+    }
+
+    @Override
+    public void setCurrentWorldSectionHeight(int currentWorldSectionHeight) {
+        this.currentWorldSectionHeight = currentWorldSectionHeight;
+    }
+
+    /**
+     * @return absolute minimum y coordinate of the current world
+     */
+    @Override
+    public int currentMinY() {
+        return currentMinY;
+    }
+
+    @Override
+    public void setCurrentMinY(int currentMinY) {
+        this.currentMinY = currentMinY;
+    }
+}

common/src/main/java/com/viaversion/viaversion/data/entity/StoredEntityImpl.java

@@ -0,0 +1,54 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2021 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viaversion.data.entity;
+
+import com.viaversion.viaversion.api.data.entity.StoredEntityData;
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public final class StoredEntityImpl implements StoredEntityData {
+    private final Map<Class<?>, Object> storedObjects = new ConcurrentHashMap<>();
+    private final EntityType type;
+
+    public StoredEntityImpl(EntityType type) {
+        this.type = type;
+    }
+
+    @Override
+    public EntityType type() {
+        return type;
+    }
+
+    @Override
+    public @Nullable <T> T get(Class<T> objectClass) {
+        return (T) storedObjects.get(objectClass);
+    }
+
+    @Override
+    public boolean has(Class<?> objectClass) {
+        return storedObjects.containsKey(objectClass);
+    }
+
+    @Override
+    public void put(Object object) {
+        storedObjects.put(object.getClass(), object);
+    }
+}

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_10to1_9_3/Protocol1_10To1_9_3_4.java

@@ -48,8 +48,8 @@ public class Protocol1_10To1_9_3_4 extends AbstractProtocol<ClientboundPackets1_
         public List<Metadata> transform(PacketWrapper wrapper, List<Metadata> inputValue) throws Exception {
             List<Metadata> metaList = new CopyOnWriteArrayList<>(inputValue);
             for (Metadata m : metaList) {
-                if (m.getId() >= 5)
+                if (m.id() >= 5)
-                    m.setId(m.getId() + 1);
+                    m.setId(m.id() + 1);
             }
             return metaList;
         }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_11to1_10/Protocol1_11To1_10.java

@@ -39,7 +39,7 @@ import com.viaversion.viaversion.protocols.protocol1_9_1_2to1_9_3_4.types.Chunk1
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.ClientboundPackets1_9_3;
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.ServerboundPackets1_9_3;
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.storage.ClientWorld;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 import com.viaversion.viaversion.rewriter.SoundRewriter;
 import com.viaversion.viaversion.util.Pair;
 
@@ -57,7 +57,8 @@ public class Protocol1_11To1_10 extends AbstractProtocol<ClientboundPackets1_9_3
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_11To1_10(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_11To1_10(this);
+        metadataRewriter.register();
 
         InventoryPackets.register(this);
 
@@ -69,7 +70,7 @@ public class Protocol1_11To1_10 extends AbstractProtocol<ClientboundPackets1_9_3
                 map(Type.BYTE); // 2 - Type
 
                 // Track Entity
-                handler(metadataRewriter.getObjectTracker());
+                handler(metadataRewriter.objectTrackerHandler());
             }
         });
 
@@ -102,7 +103,7 @@ public class Protocol1_11To1_10 extends AbstractProtocol<ClientboundPackets1_9_3
                             wrapper.set(Type.VAR_INT, 1, entType.getId());
 
                             // Register Type ID
-                            wrapper.user().get(EntityTracker1_11.class).addEntity(entityId, entType);
+                            wrapper.user().getEntityTracker(Protocol1_11To1_10.class).addEntity(entityId, entType);
                             metadataRewriter.handleMetadata(entityId, wrapper.get(Types1_9.METADATA_LIST, 0), wrapper.user());
                         }
                     }
@@ -145,7 +146,7 @@ public class Protocol1_11To1_10 extends AbstractProtocol<ClientboundPackets1_9_3
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
                         if (Via.getConfig().isHologramPatch()) {
-                            EntityTracker1_11 tracker = wrapper.user().get(EntityTracker1_11.class);
+                            EntityTracker1_11 tracker = wrapper.user().getEntityTracker(Protocol1_11To1_10.class);
                             if (tracker.isHologram(entityID)) {
                                 Double newValue = wrapper.get(Type.DOUBLE, 1);
                                 newValue -= (Via.getConfig().getHologramYOffset());
@@ -157,7 +158,7 @@ public class Protocol1_11To1_10 extends AbstractProtocol<ClientboundPackets1_9_3
             }
         });
 
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_9_3.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_9_3.DESTROY_ENTITIES);
 
         registerClientbound(ClientboundPackets1_9_3.TITLE, new PacketRemapper() {
             @Override
@@ -377,7 +378,7 @@ public class Protocol1_11To1_10 extends AbstractProtocol<ClientboundPackets1_9_3
     @Override
     public void init(UserConnection userConnection) {
         // Entity tracker
-        userConnection.put(new EntityTracker1_11(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTracker1_11(userConnection));
 
         if (!userConnection.has(ClientWorld.class))
             userConnection.put(new ClientWorld(userConnection));

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_11to1_10/metadata/MetadataRewriter1_11To1_10.java

@@ -29,15 +29,15 @@ import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.protocols.protocol1_11to1_10.EntityIdRewriter;
 import com.viaversion.viaversion.protocols.protocol1_11to1_10.Protocol1_11To1_10;
 import com.viaversion.viaversion.protocols.protocol1_11to1_10.storage.EntityTracker1_11;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 
 import java.util.List;
 import java.util.Optional;
 
-public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
+public class MetadataRewriter1_11To1_10 extends EntityRewriter<Protocol1_11To1_10> {
 
     public MetadataRewriter1_11To1_10(Protocol1_11To1_10 protocol) {
-        super(protocol, EntityTracker1_11.class);
+        super(protocol);
     }
 
     @Override
@@ -49,7 +49,7 @@ public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
 
         if (type == null) return;
         if (type.is(EntityType.ELDER_GUARDIAN) || type.is(EntityType.GUARDIAN)) { // Guardians
-            int oldid = metadata.getId();
+            int oldid = metadata.id();
             if (oldid == 12) {
                 metadata.setMetaType(MetaType1_9.Boolean);
                 boolean val = (((byte) metadata.getValue()) & 0x02) == 0x02;
@@ -58,7 +58,7 @@ public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
         }
 
         if (type.isOrHasParent(EntityType.ABSTRACT_SKELETON)) { // Skeletons
-            int oldid = metadata.getId();
+            int oldid = metadata.id();
             if (oldid == 12) {
                 metadatas.remove(metadata);
             }
@@ -68,13 +68,13 @@ public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
         }
 
         if (type.isOrHasParent(EntityType.ZOMBIE)) { // Zombie | Zombie Villager | Husk
-            if (type.is(EntityType.ZOMBIE, EntityType.HUSK) && metadata.getId() == 14) {
+            if (type.is(EntityType.ZOMBIE, EntityType.HUSK) && metadata.id() == 14) {
                 metadatas.remove(metadata);
             } else {
-                if (metadata.getId() == 15) {
+                if (metadata.id() == 15) {
                     metadata.setId(14);
                 } else {
-                    if (metadata.getId() == 14) {
+                    if (metadata.id() == 14) {
                         metadata.setId(15);
                     }
                 }
@@ -83,7 +83,7 @@ public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
 
         if (type.isOrHasParent(EntityType.ABSTRACT_HORSE)) { // Horses
             // Remap metadata id
-            int oldid = metadata.getId();
+            int oldid = metadata.id();
             if (oldid == 14) { // Type
                 metadatas.remove(metadata);
             }
@@ -99,13 +99,13 @@ public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
                 // Normal Horse
             } else {
                 // Remove 15, 16
-                if (metadata.getId() == 15 || metadata.getId() == 16) {
+                if (metadata.id() == 15 || metadata.id() == 16) {
                     metadatas.remove(metadata);
                 }
             }
             if (type.is(EntityType.DONKEY, EntityType.MULE)) {
                 // Chested Horse
-                if (metadata.getId() == 13) {
+                if (metadata.id() == 13) {
                     if ((((byte) metadata.getValue()) & 0x08) == 0x08) {
                         metadatas.add(new Metadata(15, MetaType1_9.Boolean, true));
                     } else {
@@ -116,15 +116,15 @@ public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
         }
 
         if (type.is(EntityType.ARMOR_STAND) && Via.getConfig().isHologramPatch()) {
-            Metadata flags = getMetaByIndex(11, metadatas);
+            Metadata flags = metaByIndex(11, metadatas);
-            Metadata customName = getMetaByIndex(2, metadatas);
+            Metadata customName = metaByIndex(2, metadatas);
-            Metadata customNameVisible = getMetaByIndex(3, metadatas);
+            Metadata customNameVisible = metaByIndex(3, metadatas);
-            if (metadata.getId() == 0 && flags != null && customName != null && customNameVisible != null) {
+            if (metadata.id() == 0 && flags != null && customName != null && customNameVisible != null) {
                 byte data = (byte) metadata.getValue();
                 // Check invisible | Check small | Check if custom name is empty | Check if custom name visible is true
                 if ((data & 0x20) == 0x20 && ((byte) flags.getValue() & 0x01) == 0x01
                         && !((String) customName.getValue()).isEmpty() && (boolean) customNameVisible.getValue()) {
-                    EntityTracker1_11 tracker = connection.get(EntityTracker1_11.class);
+                    EntityTracker1_11 tracker = tracker(connection);
                     if (!tracker.isHologram(entityId)) {
                         tracker.addHologram(entityId);
                         try {
@@ -147,12 +147,12 @@ public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
     }
 
     @Override
-    protected com.viaversion.viaversion.api.minecraft.entities.EntityType getTypeFromId(int type) {
+    protected com.viaversion.viaversion.api.minecraft.entities.EntityType typeFromId(int type) {
         return Entity1_11Types.getTypeFromId(type, false);
     }
 
     @Override
-    protected com.viaversion.viaversion.api.minecraft.entities.EntityType getObjectTypeFromId(int type) {
+    protected com.viaversion.viaversion.api.minecraft.entities.EntityType objectTypeFromId(int type) {
         return Entity1_11Types.getTypeFromId(type, true);
     }
 
@@ -240,7 +240,7 @@ public class MetadataRewriter1_11To1_10 extends MetadataRewriter {
 
     public static Optional<Metadata> getById(List<Metadata> metadatas, int id) {
         for (Metadata metadata : metadatas) {
-            if (metadata.getId() == id) return Optional.of(metadata);
+            if (metadata.id() == id) return Optional.of(metadata);
         }
         return Optional.empty();
     }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_11to1_10/storage/EntityTracker1_11.java

@@ -20,11 +20,11 @@ package com.viaversion.viaversion.protocols.protocol1_11to1_10.storage;
 import com.google.common.collect.Sets;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.entities.Entity1_11Types.EntityType;
-import com.viaversion.viaversion.data.EntityTracker;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 
 import java.util.Set;
 
-public class EntityTracker1_11 extends EntityTracker {
+public class EntityTracker1_11 extends EntityTrackerBase {
     private final Set<Integer> holograms = Sets.newConcurrentHashSet();
 
     public EntityTracker1_11(UserConnection user) {

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_12to1_11_1/Protocol1_12To1_11_1.java

@@ -25,6 +25,7 @@ import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.chunks.Chunk;
 import com.viaversion.viaversion.api.minecraft.chunks.ChunkSection;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_12Types;
 import com.viaversion.viaversion.api.platform.providers.ViaProviders;
 import com.viaversion.viaversion.api.protocol.AbstractProtocol;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
@@ -32,16 +33,16 @@ import com.viaversion.viaversion.api.protocol.remapper.PacketHandler;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.version.Types1_12;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_12to1_11_1.metadata.MetadataRewriter1_12To1_11_1;
 import com.viaversion.viaversion.protocols.protocol1_12to1_11_1.packets.InventoryPackets;
 import com.viaversion.viaversion.protocols.protocol1_12to1_11_1.providers.InventoryQuickMoveProvider;
-import com.viaversion.viaversion.protocols.protocol1_12to1_11_1.storage.EntityTracker1_12;
 import com.viaversion.viaversion.protocols.protocol1_9_1_2to1_9_3_4.types.Chunk1_9_3_4Type;
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.ClientboundPackets1_9_3;
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.ServerboundPackets1_9_3;
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.storage.ClientWorld;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 import com.viaversion.viaversion.rewriter.SoundRewriter;
 
 public class Protocol1_12To1_11_1 extends AbstractProtocol<ClientboundPackets1_9_3, ClientboundPackets1_12, ServerboundPackets1_9_3, ServerboundPackets1_12> {
@@ -52,7 +53,8 @@ public class Protocol1_12To1_11_1 extends AbstractProtocol<ClientboundPackets1_9
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_12To1_11_1(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_12To1_11_1(this);
+        metadataRewriter.register();
 
         InventoryPackets.register(this);
 
@@ -64,7 +66,7 @@ public class Protocol1_12To1_11_1 extends AbstractProtocol<ClientboundPackets1_9
                 map(Type.BYTE); // 2 - Type
 
                 // Track Entity
-                handler(metadataRewriter.getObjectTracker());
+                handler(metadataRewriter.objectTrackerHandler());
             }
         });
 
@@ -86,7 +88,7 @@ public class Protocol1_12To1_11_1 extends AbstractProtocol<ClientboundPackets1_9
                 map(Types1_12.METADATA_LIST); // 12 - Metadata
 
                 // Track mob and rewrite metadata
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_12.METADATA_LIST));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_12.METADATA_LIST));
             }
         });
 
@@ -153,7 +155,7 @@ public class Protocol1_12To1_11_1 extends AbstractProtocol<ClientboundPackets1_9
             }
         });
 
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_9_3.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_9_3.DESTROY_ENTITIES);
         metadataRewriter.registerMetadataRewriter(ClientboundPackets1_9_3.ENTITY_METADATA, Types1_12.METADATA_LIST);
 
         registerClientbound(ClientboundPackets1_9_3.JOIN_GAME, new PacketRemapper() {
@@ -255,7 +257,7 @@ public class Protocol1_12To1_11_1 extends AbstractProtocol<ClientboundPackets1_9
 
     @Override
     public void init(UserConnection userConnection) {
-        userConnection.put(new EntityTracker1_12(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTrackerBase(userConnection, Entity1_12Types.EntityType.PLAYER));
         if (!userConnection.has(ClientWorld.class)) {
             userConnection.put(new ClientWorld(userConnection));
         }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_12to1_11_1/metadata/MetadataRewriter1_12To1_11_1.java

@@ -24,15 +24,14 @@ import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
 import com.viaversion.viaversion.protocols.protocol1_12to1_11_1.BedRewriter;
 import com.viaversion.viaversion.protocols.protocol1_12to1_11_1.Protocol1_12To1_11_1;
-import com.viaversion.viaversion.protocols.protocol1_12to1_11_1.storage.EntityTracker1_12;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 
-public class MetadataRewriter1_12To1_11_1 extends MetadataRewriter {
+public class MetadataRewriter1_12To1_11_1 extends EntityRewriter<Protocol1_12To1_11_1> {
 
     public MetadataRewriter1_12To1_11_1(Protocol1_12To1_11_1 protocol) {
-        super(protocol, EntityTracker1_12.class);
+        super(protocol);
     }
 
     @Override
@@ -45,19 +44,19 @@ public class MetadataRewriter1_12To1_11_1 extends MetadataRewriter {
         if (type == null) return;
         // Evocation Illager aggressive property became 13
         if (type == Entity1_12Types.EntityType.EVOCATION_ILLAGER) {
-            if (metadata.getId() == 12) {
+            if (metadata.id() == 12) {
                 metadata.setId(13);
             }
         }
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_12Types.getTypeFromId(type, false);
     }
 
     @Override
-    protected EntityType getObjectTypeFromId(int type) {
+    protected EntityType objectTypeFromId(int type) {
         return Entity1_12Types.getTypeFromId(type, true);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_12to1_11_1/storage/EntityTracker1_12.java

@@ -1,29 +0,0 @@
-/*
- * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
- * Copyright (C) 2016-2021 ViaVersion and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package com.viaversion.viaversion.protocols.protocol1_12to1_11_1.storage;
-
-import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.minecraft.entities.Entity1_12Types.EntityType;
-import com.viaversion.viaversion.data.EntityTracker;
-
-public class EntityTracker1_12 extends EntityTracker {
-
-    public EntityTracker1_12(UserConnection user) {
-        super(user, EntityType.PLAYER);
-    }
-}

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13_1to1_13/Protocol1_13_1To1_13.java

@@ -20,6 +20,7 @@ package com.viaversion.viaversion.protocols.protocol1_13_1to1_13;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.data.MappingData;
 import com.viaversion.viaversion.api.data.MappingDataBase;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_13Types;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.protocol.AbstractProtocol;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
@@ -27,13 +28,13 @@ import com.viaversion.viaversion.api.protocol.remapper.PacketHandler;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.protocol.remapper.ValueTransformer;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_13_1to1_13.metadata.MetadataRewriter1_13_1To1_13;
 import com.viaversion.viaversion.protocols.protocol1_13_1to1_13.packets.EntityPackets;
 import com.viaversion.viaversion.protocols.protocol1_13_1to1_13.packets.InventoryPackets;
 import com.viaversion.viaversion.protocols.protocol1_13_1to1_13.packets.WorldPackets;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.ClientboundPackets1_13;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.ServerboundPackets1_13;
-import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.EntityTracker1_13;
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.storage.ClientWorld;
 import com.viaversion.viaversion.rewriter.RegistryType;
 import com.viaversion.viaversion.rewriter.StatisticsRewriter;
@@ -49,7 +50,8 @@ public class Protocol1_13_1To1_13 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     protected void registerPackets() {
-        new MetadataRewriter1_13_1To1_13(this);
+        MetadataRewriter1_13_1To1_13 metadataRewriter = new MetadataRewriter1_13_1To1_13(this);
+        metadataRewriter.register();
 
         EntityPackets.register(this);
         InventoryPackets.register(this);
@@ -148,7 +150,7 @@ public class Protocol1_13_1To1_13 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     public void init(UserConnection userConnection) {
-        userConnection.put(new EntityTracker1_13(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTrackerBase(userConnection, Entity1_13Types.EntityType.PLAYER));
         if (!userConnection.has(ClientWorld.class)) {
             userConnection.put(new ClientWorld(userConnection));
         }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13_1to1_13/metadata/MetadataRewriter1_13_1To1_13.java

@@ -26,48 +26,47 @@ import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_13;
 import com.viaversion.viaversion.api.type.types.Particle;
 import com.viaversion.viaversion.protocols.protocol1_13_1to1_13.Protocol1_13_1To1_13;
 import com.viaversion.viaversion.protocols.protocol1_13_1to1_13.packets.InventoryPackets;
-import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.EntityTracker1_13;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 
-public class MetadataRewriter1_13_1To1_13 extends MetadataRewriter {
+public class MetadataRewriter1_13_1To1_13 extends EntityRewriter<Protocol1_13_1To1_13> {
 
     public MetadataRewriter1_13_1To1_13(Protocol1_13_1To1_13 protocol) {
-        super(protocol, EntityTracker1_13.class);
+        super(protocol);
     }
 
     @Override
     protected void handleMetadata(int entityId, EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) {
         // 1.13 changed item to flat item (no data)
-        if (metadata.getMetaType() == MetaType1_13.Slot) {
+        if (metadata.metaType() == MetaType1_13.Slot) {
             InventoryPackets.toClient((Item) metadata.getValue());
-        } else if (metadata.getMetaType() == MetaType1_13.BlockID) {
+        } else if (metadata.metaType() == MetaType1_13.BlockID) {
             // Convert to new block id
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
-        } else if (metadata.getMetaType() == MetaType1_13.PARTICLE) {
+        } else if (metadata.metaType() == MetaType1_13.PARTICLE) {
             rewriteParticle((Particle) metadata.getValue());
         }
 
         if (type == null) return;
 
-        if (type.isOrHasParent(Entity1_13Types.EntityType.MINECART_ABSTRACT) && metadata.getId() == 9) {
+        if (type.isOrHasParent(Entity1_13Types.EntityType.MINECART_ABSTRACT) && metadata.id() == 9) {
             // New block format
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
-        } else if (type.isOrHasParent(Entity1_13Types.EntityType.ABSTRACT_ARROW) && metadata.getId() >= 7) {
+        } else if (type.isOrHasParent(Entity1_13Types.EntityType.ABSTRACT_ARROW) && metadata.id() >= 7) {
-            metadata.setId(metadata.getId() + 1); // New shooter UUID
+            metadata.setId(metadata.id() + 1); // New shooter UUID
         }
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_13Types.getTypeFromId(type, false);
     }
 
     @Override
-    protected EntityType getObjectTypeFromId(int type) {
+    protected EntityType objectTypeFromId(int type) {
         return Entity1_13Types.getTypeFromId(type, true);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13_1to1_13/packets/EntityPackets.java

@@ -26,7 +26,6 @@ import com.viaversion.viaversion.api.type.types.version.Types1_13;
 import com.viaversion.viaversion.protocols.protocol1_13_1to1_13.Protocol1_13_1To1_13;
 import com.viaversion.viaversion.protocols.protocol1_13_1to1_13.metadata.MetadataRewriter1_13_1To1_13;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.ClientboundPackets1_13;
-import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.EntityTracker1_13;
 
 public class EntityPackets {
 
@@ -60,7 +59,7 @@ public class EntityPackets {
                                 wrapper.set(Type.INT, 0, protocol.getMappingData().getNewBlockStateId(data));
                             }
                             // Register Type ID
-                            wrapper.user().get(EntityTracker1_13.class).addEntity(entityId, entType);
+                            wrapper.user().getEntityTracker(Protocol1_13_1To1_13.class).addEntity(entityId, entType);
                         }
                     }
                 });
@@ -84,7 +83,7 @@ public class EntityPackets {
                 map(Type.SHORT); // 11 - Velocity Z
                 map(Types1_13.METADATA_LIST); // 12 - Metadata
 
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_13.METADATA_LIST));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_13.METADATA_LIST));
             }
         });
 
@@ -100,11 +99,11 @@ public class EntityPackets {
                 map(Type.BYTE); // 6 - Pitch
                 map(Types1_13.METADATA_LIST); // 7 - Metadata
 
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_13.METADATA_LIST, Entity1_13Types.EntityType.PLAYER));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_13.METADATA_LIST, Entity1_13Types.EntityType.PLAYER));
             }
         });
 
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_13.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_13.DESTROY_ENTITIES);
         metadataRewriter.registerMetadataRewriter(ClientboundPackets1_13.ENTITY_METADATA, Types1_13.METADATA_LIST);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13_2to1_13_1/packets/EntityPackets.java

@@ -32,7 +32,7 @@ public class EntityPackets {
     public static void register(Protocol protocol) {
         final PacketHandler metaTypeHandler = wrapper -> {
             for (Metadata metadata : wrapper.get(Types1_13_2.METADATA_LIST, 0)) {
-                metadata.setMetaType(MetaType1_13_2.byId(metadata.getMetaType().getTypeID()));
+                metadata.setMetaType(MetaType1_13_2.byId(metadata.metaType().typeId()));
             }
         };
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13to1_12_2/Protocol1_13To1_12_2.java

@@ -35,6 +35,7 @@ import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.protocol.remapper.ValueCreator;
 import com.viaversion.viaversion.api.protocol.remapper.ValueTransformer;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_12_1to1_12.ClientboundPackets1_12_1;
 import com.viaversion.viaversion.protocols.protocol1_12_1to1_12.ServerboundPackets1_12_1;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.blockconnections.ConnectionData;
@@ -53,10 +54,9 @@ import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.providers.BlockE
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.providers.PaintingProvider;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.BlockConnectionStorage;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.BlockStorage;
-import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.EntityTracker1_13;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.TabCompleteTracker;
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.storage.ClientWorld;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 import com.viaversion.viaversion.rewriter.SoundRewriter;
 import com.viaversion.viaversion.util.ChatColorUtil;
 import com.viaversion.viaversion.util.GsonUtil;
@@ -162,7 +162,8 @@ public class Protocol1_13To1_12_2 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_13To1_12_2(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_13To1_12_2(this);
+        metadataRewriter.register();
 
         // Register grouped packet changes
         EntityPackets.register(this);
@@ -422,7 +423,7 @@ public class Protocol1_13To1_12_2 extends AbstractProtocol<ClientboundPackets1_1
                     public void handle(PacketWrapper wrapper) throws Exception {
                         // Store the player
                         int entityId = wrapper.get(Type.INT, 0);
-                        wrapper.user().get(EntityTracker1_13.class).addEntity(entityId, Entity1_13Types.EntityType.PLAYER);
+                        wrapper.user().getEntityTracker(Protocol1_13To1_12_2.class).addEntity(entityId, Entity1_13Types.EntityType.PLAYER);
 
                         ClientWorld clientChunks = wrapper.user().get(ClientWorld.class);
                         int dimensionId = wrapper.get(Type.INT, 1);
@@ -1045,7 +1046,7 @@ public class Protocol1_13To1_12_2 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     public void init(UserConnection userConnection) {
-        userConnection.put(new EntityTracker1_13(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTrackerBase(userConnection, Entity1_13Types.EntityType.PLAYER));
         userConnection.put(new TabCompleteTracker(userConnection));
         if (!userConnection.has(ClientWorld.class))
             userConnection.put(new ClientWorld(userConnection));

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13to1_12_2/metadata/MetadataRewriter1_13To1_12_2.java

@@ -30,28 +30,27 @@ import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.data.EntityTypeR
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.data.ParticleRewriter;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.packets.InventoryPackets;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.packets.WorldPackets;
-import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.EntityTracker1_13;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 
-public class MetadataRewriter1_13To1_12_2 extends MetadataRewriter {
+public class MetadataRewriter1_13To1_12_2 extends EntityRewriter<Protocol1_13To1_12_2> {
 
     public MetadataRewriter1_13To1_12_2(Protocol1_13To1_12_2 protocol) {
-        super(protocol, EntityTracker1_13.class);
+        super(protocol);
     }
 
     @Override
     protected void handleMetadata(int entityId, EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception {
         // Handle new MetaTypes
-        if (metadata.getMetaType().getTypeID() > 4) {
+        if (metadata.metaType().typeId() > 4) {
-            metadata.setMetaType(MetaType1_13.byId(metadata.getMetaType().getTypeID() + 1));
+            metadata.setMetaType(MetaType1_13.byId(metadata.metaType().typeId() + 1));
         } else {
-            metadata.setMetaType(MetaType1_13.byId(metadata.getMetaType().getTypeID()));
+            metadata.setMetaType(MetaType1_13.byId(metadata.metaType().typeId()));
         }
 
         // Handle String -> Chat DisplayName
-        if (metadata.getId() == 2) {
+        if (metadata.id() == 2) {
             metadata.setMetaType(MetaType1_13.OptChat);
             if (metadata.getValue() != null && !((String) metadata.getValue()).isEmpty()) {
                 metadata.setValue(ChatRewriter.legacyTextToJson((String) metadata.getValue()));
@@ -61,7 +60,7 @@ public class MetadataRewriter1_13To1_12_2 extends MetadataRewriter {
         }
 
         // Remap held block to match new format for remapping to flat block
-        if (type == Entity1_13Types.EntityType.ENDERMAN && metadata.getId() == 12) {
+        if (type == Entity1_13Types.EntityType.ENDERMAN && metadata.id() == 12) {
             int stateId = (int) metadata.getValue();
             int id = stateId & 4095;
             int data = stateId >> 12 & 15;
@@ -69,10 +68,10 @@ public class MetadataRewriter1_13To1_12_2 extends MetadataRewriter {
         }
 
         // 1.13 changed item to flat item (no data)
-        if (metadata.getMetaType() == MetaType1_13.Slot) {
+        if (metadata.metaType() == MetaType1_13.Slot) {
             metadata.setMetaType(MetaType1_13.Slot);
             InventoryPackets.toClient((Item) metadata.getValue());
-        } else if (metadata.getMetaType() == MetaType1_13.BlockID) {
+        } else if (metadata.metaType() == MetaType1_13.BlockID) {
             // Convert to new block id
             metadata.setValue(WorldPackets.toNewId((int) metadata.getValue()));
         }
@@ -81,18 +80,18 @@ public class MetadataRewriter1_13To1_12_2 extends MetadataRewriter {
         if (type == null) return;
 
         // Handle new colors
-        if (type == Entity1_13Types.EntityType.WOLF && metadata.getId() == 17) {
+        if (type == Entity1_13Types.EntityType.WOLF && metadata.id() == 17) {
             metadata.setValue(15 - (int) metadata.getValue());
         }
 
         // Handle new zombie meta (INDEX 15 - Boolean - Zombie is shaking while enabled)
         if (type.isOrHasParent(Entity1_13Types.EntityType.ZOMBIE)) {
-            if (metadata.getId() > 14)
+            if (metadata.id() > 14)
-                metadata.setId(metadata.getId() + 1);
+                metadata.setId(metadata.id() + 1);
         }
 
         // Handle Minecart inner block
-        if (type.isOrHasParent(Entity1_13Types.EntityType.MINECART_ABSTRACT) && metadata.getId() == 9) {
+        if (type.isOrHasParent(Entity1_13Types.EntityType.MINECART_ABSTRACT) && metadata.id() == 9) {
             // New block format
             int oldId = (int) metadata.getValue();
             int combined = (((oldId & 4095) << 4) | (oldId >> 12 & 15));
@@ -102,10 +101,10 @@ public class MetadataRewriter1_13To1_12_2 extends MetadataRewriter {
 
         // Handle other changes
         if (type == Entity1_13Types.EntityType.AREA_EFFECT_CLOUD) {
-            if (metadata.getId() == 9) {
+            if (metadata.id() == 9) {
                 int particleId = (int) metadata.getValue();
-                Metadata parameter1Meta = getMetaByIndex(10, metadatas);
+                Metadata parameter1Meta = metaByIndex(10, metadatas);
-                Metadata parameter2Meta = getMetaByIndex(11, metadatas);
+                Metadata parameter2Meta = metaByIndex(11, metadatas);
                 int parameter1 = parameter1Meta != null ? (int) parameter1Meta.getValue() : 0;
                 int parameter2 = parameter2Meta != null ? (int) parameter2Meta.getValue() : 0;
 
@@ -115,11 +114,11 @@ public class MetadataRewriter1_13To1_12_2 extends MetadataRewriter {
                 }
             }
 
-            if (metadata.getId() >= 9)
+            if (metadata.id() >= 9)
                 metadatas.remove(metadata); // Remove
         }
 
-        if (metadata.getId() == 0) {
+        if (metadata.id() == 0) {
             metadata.setValue((byte) ((byte) metadata.getValue() & ~0x10)); // Previously unused, now swimming
         }
 
@@ -127,17 +126,17 @@ public class MetadataRewriter1_13To1_12_2 extends MetadataRewriter {
     }
 
     @Override
-    public int getNewEntityId(final int oldId) {
+    public int newEntityId(final int oldId) {
         return EntityTypeRewriter.getNewId(oldId);
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_13Types.getTypeFromId(type, false);
     }
 
     @Override
-    protected EntityType getObjectTypeFromId(int type) {
+    protected EntityType objectTypeFromId(int type) {
         return Entity1_13Types.getTypeFromId(type, true);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13to1_12_2/packets/EntityPackets.java

@@ -27,7 +27,6 @@ import com.viaversion.viaversion.api.type.types.version.Types1_13;
 import com.viaversion.viaversion.protocols.protocol1_12_1to1_12.ClientboundPackets1_12_1;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.Protocol1_13To1_12_2;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.metadata.MetadataRewriter1_13To1_12_2;
-import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage.EntityTracker1_13;
 
 public class EntityPackets {
 
@@ -85,7 +84,7 @@ public class EntityPackets {
                                 wrapper.set(Type.INT, 0, data);
 
                                 // Register Type ID
-                                wrapper.user().get(EntityTracker1_13.class).addEntity(entityId, entType);
+                                wrapper.user().getEntityTracker(Protocol1_13To1_12_2.class).addEntity(entityId, entType);
                             }
                         }
                     }
@@ -110,7 +109,7 @@ public class EntityPackets {
                 map(Type.SHORT); // 11 - Velocity Z
                 map(Types1_12.METADATA_LIST, Types1_13.METADATA_LIST); // 12 - Metadata
 
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_13.METADATA_LIST));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_13.METADATA_LIST));
             }
         });
 
@@ -126,11 +125,11 @@ public class EntityPackets {
                 map(Type.BYTE); // 6 - Pitch
                 map(Types1_12.METADATA_LIST, Types1_13.METADATA_LIST); // 7 - Metadata
 
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_13.METADATA_LIST, Entity1_13Types.EntityType.PLAYER));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_13.METADATA_LIST, Entity1_13Types.EntityType.PLAYER));
             }
         });
 
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_12_1.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_12_1.DESTROY_ENTITIES);
         metadataRewriter.registerMetadataRewriter(ClientboundPackets1_12_1.ENTITY_METADATA, Types1_12.METADATA_LIST, Types1_13.METADATA_LIST);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13to1_12_2/storage/EntityTracker1_13.java

@@ -1,29 +0,0 @@
-/*
- * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
- * Copyright (C) 2016-2021 ViaVersion and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package com.viaversion.viaversion.protocols.protocol1_13to1_12_2.storage;
-
-import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.minecraft.entities.Entity1_13Types.EntityType;
-import com.viaversion.viaversion.data.EntityTracker;
-
-public class EntityTracker1_13 extends EntityTracker {
-
-    public EntityTracker1_13(UserConnection user) {
-        super(user, EntityType.PLAYER);
-    }
-}

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14_1to1_14/Protocol1_14_1To1_14.java

@@ -18,13 +18,14 @@
 package com.viaversion.viaversion.protocols.protocol1_14_1to1_14;
 
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_14Types;
 import com.viaversion.viaversion.api.protocol.AbstractProtocol;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_14_1to1_14.metadata.MetadataRewriter1_14_1To1_14;
 import com.viaversion.viaversion.protocols.protocol1_14_1to1_14.packets.EntityPackets;
-import com.viaversion.viaversion.protocols.protocol1_14_1to1_14.storage.EntityTracker1_14_1;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.ClientboundPackets1_14;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.ServerboundPackets1_14;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 
 public class Protocol1_14_1To1_14 extends AbstractProtocol<ClientboundPackets1_14, ClientboundPackets1_14, ServerboundPackets1_14, ServerboundPackets1_14> {
 
@@ -34,13 +35,14 @@ public class Protocol1_14_1To1_14 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_14_1To1_14(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_14_1To1_14(this);
+        metadataRewriter.register();
 
         EntityPackets.register(this);
     }
 
     @Override
     public void init(UserConnection userConnection) {
-        userConnection.put(new EntityTracker1_14_1(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTrackerBase(userConnection, Entity1_14Types.PLAYER));
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14_1to1_14/metadata/MetadataRewriter1_14_1To1_14.java

@@ -22,15 +22,14 @@ import com.viaversion.viaversion.api.minecraft.entities.Entity1_14Types;
 import com.viaversion.viaversion.api.minecraft.entities.EntityType;
 import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
 import com.viaversion.viaversion.protocols.protocol1_14_1to1_14.Protocol1_14_1To1_14;
-import com.viaversion.viaversion.protocols.protocol1_14_1to1_14.storage.EntityTracker1_14_1;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 
-public class MetadataRewriter1_14_1To1_14 extends MetadataRewriter {
+public class MetadataRewriter1_14_1To1_14 extends EntityRewriter<Protocol1_14_1To1_14> {
 
     public MetadataRewriter1_14_1To1_14(Protocol1_14_1To1_14 protocol) {
-        super(protocol, EntityTracker1_14_1.class);
+        super(protocol);
     }
 
     @Override
@@ -38,14 +37,14 @@ public class MetadataRewriter1_14_1To1_14 extends MetadataRewriter {
         if (type == null) return;
 
         if (type == Entity1_14Types.VILLAGER || type == Entity1_14Types.WANDERING_TRADER) {
-            if (metadata.getId() >= 15) {
+            if (metadata.id() >= 15) {
-                metadata.setId(metadata.getId() + 1);
+                metadata.setId(metadata.id() + 1);
             }
         }
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_14Types.getTypeFromId(type);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14_1to1_14/packets/EntityPackets.java

@@ -47,11 +47,11 @@ public class EntityPackets {
                 map(Type.SHORT); // 11 - Velocity Z
                 map(Types1_14.METADATA_LIST); // 12 - Metadata
 
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_14.METADATA_LIST));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_14.METADATA_LIST));
             }
         });
 
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_14.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_14.DESTROY_ENTITIES);
 
         protocol.registerClientbound(ClientboundPackets1_14.SPAWN_PLAYER, new PacketRemapper() {
             @Override
@@ -65,7 +65,7 @@ public class EntityPackets {
                 map(Type.BYTE); // 6 - Pitch
                 map(Types1_14.METADATA_LIST); // 7 - Metadata
 
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_14.METADATA_LIST, Entity1_14Types.PLAYER));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_14.METADATA_LIST, Entity1_14Types.PLAYER));
             }
         });
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14to1_13_2/Protocol1_14To1_13_2.java

@@ -36,7 +36,7 @@ import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.packets.WorldPac
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.storage.EntityTracker1_14;
 import com.viaversion.viaversion.protocols.protocol1_9_3to1_9_1_2.storage.ClientWorld;
 import com.viaversion.viaversion.rewriter.ComponentRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 import com.viaversion.viaversion.rewriter.SoundRewriter;
 import com.viaversion.viaversion.rewriter.StatisticsRewriter;
 
@@ -50,7 +50,8 @@ public class Protocol1_14To1_13_2 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_14To1_13_2(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_14To1_13_2(this);
+        metadataRewriter.register();
 
         InventoryPackets.register(this);
         EntityPackets.register(this);
@@ -58,7 +59,7 @@ public class Protocol1_14To1_13_2 extends AbstractProtocol<ClientboundPackets1_1
         PlayerPackets.register(this);
 
         new SoundRewriter(this).registerSound(ClientboundPackets1_13.SOUND);
-        new StatisticsRewriter(this, metadataRewriter::getNewEntityId).register(ClientboundPackets1_13.STATISTICS);
+        new StatisticsRewriter(this, metadataRewriter::newEntityId).register(ClientboundPackets1_13.STATISTICS);
 
         ComponentRewriter componentRewriter = new ComponentRewriter1_14(this);
         componentRewriter.registerChatMessage(ClientboundPackets1_13.CHAT_MESSAGE);
@@ -146,7 +147,7 @@ public class Protocol1_14To1_13_2 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     public void init(UserConnection userConnection) {
-        userConnection.put(new EntityTracker1_14(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTracker1_14(userConnection));
         if (!userConnection.has(ClientWorld.class)) {
             userConnection.put(new ClientWorld(userConnection));
         }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14to1_13_2/metadata/MetadataRewriter1_14To1_13_2.java

@@ -32,41 +32,41 @@ import com.viaversion.viaversion.api.type.types.Particle;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.Protocol1_14To1_13_2;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.packets.InventoryPackets;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.storage.EntityTracker1_14;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 
 import java.util.List;
 
-public class MetadataRewriter1_14To1_13_2 extends MetadataRewriter {
+public class MetadataRewriter1_14To1_13_2 extends EntityRewriter<Protocol1_14To1_13_2> {
 
     public MetadataRewriter1_14To1_13_2(Protocol1_14To1_13_2 protocol) {
-        super(protocol, EntityTracker1_14.class);
+        super(protocol);
         mapTypes(Entity1_13Types.EntityType.values(), Entity1_14Types.class);
-        mapType(Entity1_13Types.EntityType.OCELOT, Entity1_14Types.CAT); //TODO remap untamed ocelots to ocelots?
+        mapEntityType(Entity1_13Types.EntityType.OCELOT, Entity1_14Types.CAT); //TODO remap untamed ocelots to ocelots?
     }
 
     @Override
     protected void handleMetadata(int entityId, EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception {
-        metadata.setMetaType(MetaType1_14.byId(metadata.getMetaType().getTypeID()));
+        metadata.setMetaType(MetaType1_14.byId(metadata.metaType().typeId()));
 
-        EntityTracker1_14 tracker = connection.get(EntityTracker1_14.class);
+        EntityTracker1_14 tracker = tracker(connection);
 
-        if (metadata.getMetaType() == MetaType1_14.Slot) {
+        if (metadata.metaType() == MetaType1_14.Slot) {
             InventoryPackets.toClient((Item) metadata.getValue());
-        } else if (metadata.getMetaType() == MetaType1_14.BlockID) {
+        } else if (metadata.metaType() == MetaType1_14.BlockID) {
             // Convert to new block id
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
-        } else if (metadata.getMetaType() == MetaType1_14.PARTICLE) {
+        } else if (metadata.metaType() == MetaType1_14.PARTICLE) {
             rewriteParticle((Particle) metadata.getValue());
         }
 
         if (type == null) return;
 
         //Metadata 6 added to abstract_entity
-        if (metadata.getId() > 5) {
+        if (metadata.id() > 5) {
-            metadata.setId(metadata.getId() + 1);
+            metadata.setId(metadata.id() + 1);
         }
-        if (metadata.getId() == 8 && type.isOrHasParent(Entity1_14Types.LIVINGENTITY)) {
+        if (metadata.id() == 8 && type.isOrHasParent(Entity1_14Types.LIVINGENTITY)) {
             final float v = ((Number) metadata.getValue()).floatValue();
             if (Float.isNaN(v) && Via.getConfig().is1_14HealthNaNFix()) {
                 metadata.setValue(1F);
@@ -74,12 +74,12 @@ public class MetadataRewriter1_14To1_13_2 extends MetadataRewriter {
         }
 
         //Metadata 12 added to living_entity
-        if (metadata.getId() > 11 && type.isOrHasParent(Entity1_14Types.LIVINGENTITY)) {
+        if (metadata.id() > 11 && type.isOrHasParent(Entity1_14Types.LIVINGENTITY)) {
-            metadata.setId(metadata.getId() + 1);
+            metadata.setId(metadata.id() + 1);
         }
 
         if (type.isOrHasParent(Entity1_14Types.ABSTRACT_INSENTIENT)) {
-            if (metadata.getId() == 13) {
+            if (metadata.id() == 13) {
                 tracker.setInsentientData(entityId, (byte) ((((Number) metadata.getValue()).byteValue() & ~0x4)
                         | (tracker.getInsentientData(entityId) & 0x4))); // New attacking metadata
                 metadata.setValue(tracker.getInsentientData(entityId));
@@ -87,37 +87,37 @@ public class MetadataRewriter1_14To1_13_2 extends MetadataRewriter {
         }
 
         if (type.isOrHasParent(Entity1_14Types.PLAYER)) {
-            if (entityId != tracker.getClientEntityId()) {
+            if (entityId != tracker.clientEntityId()) {
-                if (metadata.getId() == 0) {
+                if (metadata.id() == 0) {
                     byte flags = ((Number) metadata.getValue()).byteValue();
                     // Mojang overrides the client-side pose updater, see OtherPlayerEntity#updateSize
                     tracker.setEntityFlags(entityId, flags);
-                } else if (metadata.getId() == 7) {
+                } else if (metadata.id() == 7) {
                     tracker.setRiptide(entityId, (((Number) metadata.getValue()).byteValue() & 0x4) != 0);
                 }
-                if (metadata.getId() == 0 || metadata.getId() == 7) {
+                if (metadata.id() == 0 || metadata.id() == 7) {
                     metadatas.add(new Metadata(6, MetaType1_14.Pose, recalculatePlayerPose(entityId, tracker)));
                 }
             }
         } else if (type.isOrHasParent(Entity1_14Types.ZOMBIE)) {
-            if (metadata.getId() == 16) {
+            if (metadata.id() == 16) {
                 tracker.setInsentientData(entityId, (byte) ((tracker.getInsentientData(entityId) & ~0x4)
                         | ((boolean) metadata.getValue() ? 0x4 : 0))); // New attacking
                 metadatas.remove(metadata);  // "Are hands held up"
                 metadatas.add(new Metadata(13, MetaType1_14.Byte, tracker.getInsentientData(entityId)));
-            } else if (metadata.getId() > 16) {
+            } else if (metadata.id() > 16) {
-                metadata.setId(metadata.getId() - 1);
+                metadata.setId(metadata.id() - 1);
             }
         }
 
         if (type.isOrHasParent(Entity1_14Types.MINECART_ABSTRACT)) {
-            if (metadata.getId() == 10) {
+            if (metadata.id() == 10) {
                 // New block format
                 int data = (int) metadata.getValue();
                 metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
             }
         } else if (type.is(Entity1_14Types.HORSE)) {
-            if (metadata.getId() == 18) {
+            if (metadata.id() == 18) {
                 metadatas.remove(metadata);
 
                 int armorType = (int) metadata.getValue();
@@ -137,29 +137,29 @@ public class MetadataRewriter1_14To1_13_2 extends MetadataRewriter {
                 equipmentPacket.send(Protocol1_14To1_13_2.class);
             }
         } else if (type.is(Entity1_14Types.VILLAGER)) {
-            if (metadata.getId() == 15) {
+            if (metadata.id() == 15) {
                 // plains
                 metadata.setValue(new VillagerData(2, getNewProfessionId((int) metadata.getValue()), 0));
                 metadata.setMetaType(MetaType1_14.VillagerData);
             }
         } else if (type.is(Entity1_14Types.ZOMBIE_VILLAGER)) {
-            if (metadata.getId() == 18) {
+            if (metadata.id() == 18) {
                 // plains
                 metadata.setValue(new VillagerData(2, getNewProfessionId((int) metadata.getValue()), 0));
                 metadata.setMetaType(MetaType1_14.VillagerData);
             }
         } else if (type.isOrHasParent(Entity1_14Types.ABSTRACT_ARROW)) {
-            if (metadata.getId() >= 9) { // New piercing
+            if (metadata.id() >= 9) { // New piercing
-                metadata.setId(metadata.getId() + 1);
+                metadata.setId(metadata.id() + 1);
             }
         } else if (type.is(Entity1_14Types.FIREWORK_ROCKET)) {
-            if (metadata.getId() == 8) {
+            if (metadata.id() == 8) {
                 if (metadata.getValue().equals(0))
                     metadata.setValue(null); // https://bugs.mojang.com/browse/MC-111480
                 metadata.setMetaType(MetaType1_14.OptVarInt);
             }
         } else if (type.isOrHasParent(Entity1_14Types.ABSTRACT_SKELETON)) {
-            if (metadata.getId() == 14) {
+            if (metadata.id() == 14) {
                 tracker.setInsentientData(entityId, (byte) ((tracker.getInsentientData(entityId) & ~0x4)
                         | ((boolean) metadata.getValue() ? 0x4 : 0))); // New attacking
                 metadatas.remove(metadata);  // "Is swinging arms"
@@ -168,7 +168,7 @@ public class MetadataRewriter1_14To1_13_2 extends MetadataRewriter {
         }
 
         if (type.isOrHasParent(Entity1_14Types.ABSTRACT_ILLAGER_BASE)) {
-            if (metadata.getId() == 14) {
+            if (metadata.id() == 14) {
                 tracker.setInsentientData(entityId, (byte) ((tracker.getInsentientData(entityId) & ~0x4)
                         | (((Number) metadata.getValue()).byteValue() != 0 ? 0x4 : 0))); // New attacking
                 metadatas.remove(metadata);  // "Has target (aggressive state)"
@@ -178,14 +178,14 @@ public class MetadataRewriter1_14To1_13_2 extends MetadataRewriter {
 
         // TODO Are witch and ravager also abstract illagers? They all inherit the new metadata 14 added in 19w13a
         if (type.is(Entity1_14Types.WITCH) || type.is(Entity1_14Types.RAVAGER) || type.isOrHasParent(Entity1_14Types.ABSTRACT_ILLAGER_BASE)) {
-            if (metadata.getId() >= 14) {  // TODO 19w13 added a new boolean (raid participant - is celebrating) with id 14
+            if (metadata.id() >= 14) {  // TODO 19w13 added a new boolean (raid participant - is celebrating) with id 14
-                metadata.setId(metadata.getId() + 1);
+                metadata.setId(metadata.id() + 1);
             }
         }
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_14Types.getTypeFromId(type);
     }
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14to1_13_2/packets/EntityPackets.java

@@ -67,7 +67,7 @@ public class EntityPackets {
                         int typeId = wrapper.get(Type.VAR_INT, 1);
 
                         Entity1_13Types.EntityType type1_13 = Entity1_13Types.getTypeFromId(typeId, true);
-                        typeId = metadataRewriter.getNewEntityId(type1_13.getId());
+                        typeId = metadataRewriter.newEntityId(type1_13.getId());
                         EntityType type1_14 = Entity1_14Types.getTypeFromId(typeId);
 
                         if (type1_14 != null) {
@@ -111,7 +111,7 @@ public class EntityPackets {
                             }
 
                             // Register Type ID
-                            wrapper.user().get(EntityTracker1_14.class).addEntity(entityId, type1_14);
+                            wrapper.user().getEntityTracker(Protocol1_14To1_13_2.class).addEntity(entityId, type1_14);
                         }
 
                         wrapper.set(Type.VAR_INT, 1, typeId);
@@ -137,7 +137,7 @@ public class EntityPackets {
                 map(Type.SHORT); // 11 - Velocity Z
                 map(Types1_13_2.METADATA_LIST, Types1_14.METADATA_LIST); // 12 - Metadata
 
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_14.METADATA_LIST));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_14.METADATA_LIST));
             }
         });
 
@@ -164,7 +164,7 @@ public class EntityPackets {
                 map(Type.BYTE); // 6 - Pitch
                 map(Types1_13_2.METADATA_LIST, Types1_14.METADATA_LIST); // 7 - Metadata
 
-                handler(metadataRewriter.getTrackerAndRewriter(Types1_14.METADATA_LIST, Entity1_14Types.PLAYER));
+                handler(metadataRewriter.trackerAndRewriterHandler(Types1_14.METADATA_LIST, Entity1_14Types.PLAYER));
             }
         });
 
@@ -177,14 +177,14 @@ public class EntityPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         short animation = wrapper.passthrough(Type.UNSIGNED_BYTE);
                         if (animation == 2) {  //Leave bed
-                            EntityTracker1_14 tracker = wrapper.user().get(EntityTracker1_14.class);
+                            EntityTracker1_14 tracker = wrapper.user().getEntityTracker(Protocol1_14To1_13_2.class);
                             int entityId = wrapper.get(Type.VAR_INT, 0);
                             tracker.setSleeping(entityId, false);
 
                             PacketWrapper metadataPacket = wrapper.create(0x43);
                             metadataPacket.write(Type.VAR_INT, entityId);
                             List<Metadata> metadataList = new LinkedList<>();
-                            if (tracker.getClientEntityId() != entityId) {
+                            if (tracker.clientEntityId() != entityId) {
                                 metadataList.add(new Metadata(6, MetaType1_14.Pose, MetadataRewriter1_14To1_13_2.recalculatePlayerPose(entityId, tracker)));
                             }
                             metadataList.add(new Metadata(12, MetaType1_14.OptPosition, null));
@@ -203,14 +203,14 @@ public class EntityPackets {
                 handler(new PacketHandler() {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
-                        EntityTracker1_14 tracker = wrapper.user().get(EntityTracker1_14.class);
+                        EntityTracker1_14 tracker = wrapper.user().getEntityTracker(Protocol1_14To1_13_2.class);
                         int entityId = wrapper.get(Type.VAR_INT, 0);
                         tracker.setSleeping(entityId, true);
 
                         Position position = wrapper.read(Type.POSITION);
                         List<Metadata> metadataList = new LinkedList<>();
                         metadataList.add(new Metadata(12, MetaType1_14.OptPosition, position));
-                        if (tracker.getClientEntityId() != entityId) {
+                        if (tracker.clientEntityId() != entityId) {
                             metadataList.add(new Metadata(6, MetaType1_14.Pose, MetadataRewriter1_14To1_13_2.recalculatePlayerPose(entityId, tracker)));
                         }
                         wrapper.write(Types1_14.METADATA_LIST, metadataList);
@@ -219,7 +219,7 @@ public class EntityPackets {
             }
         });
 
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_13.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_13.DESTROY_ENTITIES);
         metadataRewriter.registerMetadataRewriter(ClientboundPackets1_13.ENTITY_METADATA, Types1_13_2.METADATA_LIST, Types1_14.METADATA_LIST);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14to1_13_2/packets/InventoryPackets.java

@@ -158,7 +158,8 @@ public class InventoryPackets {
                             wrapper.read(Type.STRING); // Remove channel
 
                             int windowId = wrapper.read(Type.INT);
-                            wrapper.user().get(EntityTracker1_14.class).setLatestTradeWindowId(windowId);
+                            EntityTracker1_14 tracker = wrapper.user().getEntityTracker(Protocol1_14To1_13_2.class);
+                            tracker.setLatestTradeWindowId(windowId);
                             wrapper.write(Type.VAR_INT, windowId);
 
                             int size = wrapper.passthrough(Type.UNSIGNED_BYTE);
@@ -233,7 +234,8 @@ public class InventoryPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         // Selecting trade now moves the items, we need to resync the inventory
                         PacketWrapper resyncPacket = wrapper.create(0x08);
-                        resyncPacket.write(Type.UNSIGNED_BYTE, ((short) wrapper.user().get(EntityTracker1_14.class).getLatestTradeWindowId())); // 0 - Window ID
+                        EntityTracker1_14 tracker = wrapper.user().getEntityTracker(Protocol1_14To1_13_2.class);
+                        resyncPacket.write(Type.UNSIGNED_BYTE, ((short) tracker.getLatestTradeWindowId())); // 0 - Window ID
                         resyncPacket.write(Type.SHORT, ((short) -999)); // 1 - Slot
                         resyncPacket.write(Type.BYTE, (byte) 2); // 2 - Button - End left click
                         resyncPacket.write(Type.SHORT, ((short) ThreadLocalRandom.current().nextInt())); // 3 - Action number

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14to1_13_2/packets/WorldPackets.java

@@ -240,7 +240,7 @@ public class WorldPackets {
                             lightPacket.write(Type.BYTE_ARRAY_PRIMITIVE, section.getLight().getBlockLight());
                         }
 
-                        EntityTracker1_14 entityTracker = wrapper.user().get(EntityTracker1_14.class);
+                        EntityTracker1_14 entityTracker = wrapper.user().getEntityTracker(Protocol1_14To1_13_2.class);
                         int diffX = Math.abs(entityTracker.getChunkCenterX() - chunk.getX());
                         int diffZ = Math.abs(entityTracker.getChunkCenterZ() - chunk.getZ());
                         if (entityTracker.isForceSendCenterChunk()
@@ -315,7 +315,7 @@ public class WorldPackets {
 
                         Entity1_14Types entType = Entity1_14Types.PLAYER;
                         // Register Type ID
-                        EntityTracker1_14 tracker = wrapper.user().get(EntityTracker1_14.class);
+                        EntityTracker1_14 tracker = wrapper.user().getEntityTracker(Protocol1_14To1_13_2.class);
                         tracker.addEntity(entityId, entType);
                         tracker.setClientEntityId(entityId);
                     }
@@ -364,7 +364,7 @@ public class WorldPackets {
                         ClientWorld clientWorld = wrapper.user().get(ClientWorld.class);
                         int dimensionId = wrapper.get(Type.INT, 0);
                         clientWorld.setEnvironment(dimensionId);
-                        EntityTracker1_14 entityTracker = wrapper.user().get(EntityTracker1_14.class);
+                        EntityTracker1_14 entityTracker = wrapper.user().getEntityTracker(Protocol1_14To1_13_2.class);
                         // The client may reset the center chunk if dimension is changed
                         entityTracker.setForceSendCenterChunk(true);
                     }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_14to1_13_2/storage/EntityTracker1_14.java

@@ -21,14 +21,14 @@ import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.entities.Entity1_14Types;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.type.Type;
-import com.viaversion.viaversion.data.EntityTracker;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.Protocol1_14To1_13_2;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.packets.WorldPackets;
 
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
-public class EntityTracker1_14 extends EntityTracker {
+public class EntityTracker1_14 extends EntityTrackerBase {
     private final Map<Integer, Byte> insentientData = new ConcurrentHashMap<>();
     // 0x1 = sleeping, 0x2 = riptide
     private final Map<Integer, Byte> sleepingAndRiptideData = new ConcurrentHashMap<>();
@@ -91,10 +91,10 @@ public class EntityTracker1_14 extends EntityTracker {
     }
 
     @Override
-    public void onExternalJoinGame(int playerEntityId) {
+    public void setClientEntityId(int playerEntityId) {
-        super.onExternalJoinGame(playerEntityId);
+        super.setClientEntityId(playerEntityId);
 
-        PacketWrapper setViewDistance = PacketWrapper.create(0x41, null, getUser());
+        PacketWrapper setViewDistance = PacketWrapper.create(0x41, null, user());
         setViewDistance.write(Type.VAR_INT, WorldPackets.SERVERSIDE_VIEW_DISTANCE);
         try {
             setViewDistance.send(Protocol1_14To1_13_2.class, true, true);

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_15to1_14_4/Protocol1_15To1_14_4.java

@@ -18,9 +18,11 @@
 package com.viaversion.viaversion.protocols.protocol1_15to1_14_4;
 
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_15Types;
 import com.viaversion.viaversion.api.protocol.AbstractProtocol;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.ClientboundPackets1_14;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.ServerboundPackets1_14;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.data.MappingData;
@@ -29,8 +31,7 @@ import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.packets.EntityPa
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.packets.InventoryPackets;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.packets.PlayerPackets;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.packets.WorldPackets;
-import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.storage.EntityTracker1_15;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 import com.viaversion.viaversion.rewriter.RegistryType;
 import com.viaversion.viaversion.rewriter.SoundRewriter;
 import com.viaversion.viaversion.rewriter.StatisticsRewriter;
@@ -47,7 +48,8 @@ public class Protocol1_15To1_14_4 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_15To1_14_4(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_15To1_14_4(this);
+        metadataRewriter.register();
 
         EntityPackets.register(this);
         PlayerPackets.register(this);
@@ -58,7 +60,7 @@ public class Protocol1_15To1_14_4 extends AbstractProtocol<ClientboundPackets1_1
         soundRewriter.registerSound(ClientboundPackets1_14.ENTITY_SOUND); // Entity Sound Effect (added somewhere in 1.14)
         soundRewriter.registerSound(ClientboundPackets1_14.SOUND);
 
-        new StatisticsRewriter(this, metadataRewriter::getNewEntityId).register(ClientboundPackets1_14.STATISTICS);
+        new StatisticsRewriter(this, metadataRewriter::newEntityId).register(ClientboundPackets1_14.STATISTICS);
 
         registerServerbound(ServerboundPackets1_14.EDIT_BOOK, new PacketRemapper() {
             @Override
@@ -82,8 +84,8 @@ public class Protocol1_15To1_14_4 extends AbstractProtocol<ClientboundPackets1_1
     }
 
     @Override
-    public void init(UserConnection userConnection) {
+    public void init(UserConnection connection) {
-        userConnection.put(new EntityTracker1_15(userConnection));
+        addEntityTracker(connection, new EntityTrackerBase(connection, Entity1_15Types.PLAYER));
     }
 
     @Override

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_15to1_14_4/metadata/MetadataRewriter1_15To1_14_4.java

@@ -28,41 +28,40 @@ import com.viaversion.viaversion.api.type.types.Particle;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.Protocol1_15To1_14_4;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.packets.EntityPackets;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.packets.InventoryPackets;
-import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.storage.EntityTracker1_15;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 
-public class MetadataRewriter1_15To1_14_4 extends MetadataRewriter {
+public class MetadataRewriter1_15To1_14_4 extends EntityRewriter<Protocol1_15To1_14_4> {
 
     public MetadataRewriter1_15To1_14_4(Protocol1_15To1_14_4 protocol) {
-        super(protocol, EntityTracker1_15.class);
+        super(protocol);
     }
 
     @Override
     public void handleMetadata(int entityId, EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception {
-        if (metadata.getMetaType() == MetaType1_14.Slot) {
+        if (metadata.metaType() == MetaType1_14.Slot) {
             InventoryPackets.toClient((Item) metadata.getValue());
-        } else if (metadata.getMetaType() == MetaType1_14.BlockID) {
+        } else if (metadata.metaType() == MetaType1_14.BlockID) {
             // Convert to new block id
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
-        } else if (metadata.getMetaType() == MetaType1_13.PARTICLE) {
+        } else if (metadata.metaType() == MetaType1_13.PARTICLE) {
             rewriteParticle((Particle) metadata.getValue());
         }
 
         if (type == null) return;
 
         if (type.isOrHasParent(Entity1_15Types.MINECART_ABSTRACT)
-                && metadata.getId() == 10) {
+                && metadata.id() == 10) {
             // Convert to new block id
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
         }
 
         // Metadata 12 added to abstract_living
-        if (metadata.getId() > 11 && type.isOrHasParent(Entity1_15Types.LIVINGENTITY)) {
+        if (metadata.id() > 11 && type.isOrHasParent(Entity1_15Types.LIVINGENTITY)) {
-            metadata.setId(metadata.getId() + 1); //TODO is it 11 or 12? what is it for?
+            metadata.setId(metadata.id() + 1); //TODO is it 11 or 12? what is it for?
         }
 
         //NOTES:
@@ -70,21 +69,21 @@ public class MetadataRewriter1_15To1_14_4 extends MetadataRewriter {
         //new boolean with id 17 for enderman
 
         if (type.isOrHasParent(Entity1_15Types.WOLF)) {
-            if (metadata.getId() == 18) {
+            if (metadata.id() == 18) {
                 metadatas.remove(metadata);
-            } else if (metadata.getId() > 18) {
+            } else if (metadata.id() > 18) {
-                metadata.setId(metadata.getId() - 1);
+                metadata.setId(metadata.id() - 1);
             }
         }
     }
 
     @Override
-    public int getNewEntityId(final int oldId) {
+    public int newEntityId(final int oldId) {
         return EntityPackets.getNewEntityId(oldId);
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_15Types.getTypeFromId(type);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_15to1_14_4/packets/EntityPackets.java

@@ -27,8 +27,7 @@ import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.ClientboundPacke
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.ClientboundPackets1_15;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.Protocol1_15To1_14_4;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.metadata.MetadataRewriter1_15To1_14_4;
-import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.storage.EntityTracker1_15;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 
@@ -37,7 +36,7 @@ public class EntityPackets {
     public static void register(Protocol1_15To1_14_4 protocol) {
         MetadataRewriter1_15To1_14_4 metadataRewriter = protocol.get(MetadataRewriter1_15To1_14_4.class);
 
-        metadataRewriter.registerSpawnTrackerWithData(ClientboundPackets1_14.SPAWN_ENTITY, Entity1_15Types.FALLING_BLOCK);
+        metadataRewriter.registerTrackerWithData(ClientboundPackets1_14.SPAWN_ENTITY, Entity1_15Types.FALLING_BLOCK);
 
         protocol.registerClientbound(ClientboundPackets1_14.SPAWN_MOB, new PacketRemapper() {
             @Override
@@ -55,7 +54,7 @@ public class EntityPackets {
                 map(Type.SHORT); // 10 - Velocity Y
                 map(Type.SHORT); // 11 - Velocity Z
 
-                handler(metadataRewriter.getTracker());
+                handler(metadataRewriter.trackerHandler());
                 handler(wrapper -> sendMetadataPacket(wrapper, wrapper.get(Type.VAR_INT, 0), metadataRewriter));
             }
         });
@@ -73,7 +72,7 @@ public class EntityPackets {
 
                 handler(wrapper -> {
                     int entityId = wrapper.get(Type.VAR_INT, 0);
-                    wrapper.user().get(EntityTracker1_15.class).addEntity(entityId, Entity1_15Types.PLAYER);
+                    wrapper.user().getEntityTracker(Protocol1_15To1_14_4.class).addEntity(entityId, Entity1_15Types.PLAYER);
 
                     sendMetadataPacket(wrapper, entityId, metadataRewriter);
                 });
@@ -81,10 +80,10 @@ public class EntityPackets {
         });
 
         metadataRewriter.registerMetadataRewriter(ClientboundPackets1_14.ENTITY_METADATA, Types1_14.METADATA_LIST);
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_14.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_14.DESTROY_ENTITIES);
     }
 
-    private static void sendMetadataPacket(PacketWrapper wrapper, int entityId, MetadataRewriter rewriter) throws Exception {
+    private static void sendMetadataPacket(PacketWrapper wrapper, int entityId, EntityRewriter rewriter) throws Exception {
         // Meta is no longer included in the spawn packets, but sent separately
         List<Metadata> metadata = wrapper.read(Types1_14.METADATA_LIST);
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_15to1_14_4/packets/PlayerPackets.java

@@ -18,12 +18,13 @@
 package com.viaversion.viaversion.protocols.protocol1_15to1_14_4.packets;
 
 import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
 import com.viaversion.viaversion.api.minecraft.entities.Entity1_15Types;
 import com.viaversion.viaversion.api.protocol.Protocol;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.ClientboundPackets1_14;
-import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.storage.EntityTracker1_15;
+import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.Protocol1_15To1_14_4;
 
 public class PlayerPackets {
 
@@ -45,7 +46,7 @@ public class PlayerPackets {
 
                 handler(wrapper -> {
                     // Register Type ID
-                    EntityTracker1_15 tracker = wrapper.user().get(EntityTracker1_15.class);
+                    EntityTracker tracker = wrapper.user().getEntityTracker(Protocol1_15To1_14_4.class);
                     int entityId = wrapper.get(Type.INT, 0);
                     tracker.addEntity(entityId, Entity1_15Types.PLAYER);
                 });

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_16_2to1_16_1/Protocol1_16_2To1_16_1.java

@@ -18,18 +18,19 @@
 package com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1;
 
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_16_2Types;
 import com.viaversion.viaversion.api.protocol.AbstractProtocol;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.data.MappingData;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.metadata.MetadataRewriter1_16_2To1_16_1;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.packets.EntityPackets;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.packets.InventoryPackets;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.packets.WorldPackets;
-import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.storage.EntityTracker1_16_2;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.ClientboundPackets1_16;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.ServerboundPackets1_16;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 import com.viaversion.viaversion.rewriter.RegistryType;
 import com.viaversion.viaversion.rewriter.SoundRewriter;
 import com.viaversion.viaversion.rewriter.StatisticsRewriter;
@@ -46,16 +47,17 @@ public class Protocol1_16_2To1_16_1 extends AbstractProtocol<ClientboundPackets1
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_16_2To1_16_1(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_16_2To1_16_1(this);
+        metadataRewriter.register();
 
         EntityPackets.register(this);
         WorldPackets.register(this);
         InventoryPackets.register(this);
 
-        tagRewriter = new TagRewriter(this, metadataRewriter::getNewEntityId);
+        tagRewriter = new TagRewriter(this, metadataRewriter::newEntityId);
         tagRewriter.register(ClientboundPackets1_16.TAGS, RegistryType.ENTITY);
 
-        new StatisticsRewriter(this, metadataRewriter::getNewEntityId).register(ClientboundPackets1_16.STATISTICS);
+        new StatisticsRewriter(this, metadataRewriter::newEntityId).register(ClientboundPackets1_16.STATISTICS);
 
         SoundRewriter soundRewriter = new SoundRewriter(this);
         soundRewriter.registerSound(ClientboundPackets1_16.SOUND);
@@ -112,7 +114,7 @@ public class Protocol1_16_2To1_16_1 extends AbstractProtocol<ClientboundPackets1
 
     @Override
     public void init(UserConnection userConnection) {
-        userConnection.put(new EntityTracker1_16_2(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTrackerBase(userConnection, Entity1_16_2Types.PLAYER));
     }
 
     @Override

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_16_2to1_16_1/metadata/MetadataRewriter1_16_2To1_16_1.java

@@ -27,49 +27,48 @@ import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_14;
 import com.viaversion.viaversion.api.type.types.Particle;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.Protocol1_16_2To1_16_1;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.packets.InventoryPackets;
-import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.storage.EntityTracker1_16_2;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 
-public class MetadataRewriter1_16_2To1_16_1 extends MetadataRewriter {
+public class MetadataRewriter1_16_2To1_16_1 extends EntityRewriter<Protocol1_16_2To1_16_1> {
 
     public MetadataRewriter1_16_2To1_16_1(Protocol1_16_2To1_16_1 protocol) {
-        super(protocol, EntityTracker1_16_2.class);
+        super(protocol);
         mapTypes(Entity1_16Types.values(), Entity1_16_2Types.class);
     }
 
     @Override
     public void handleMetadata(int entityId, EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception {
-        if (metadata.getMetaType() == MetaType1_14.Slot) {
+        if (metadata.metaType() == MetaType1_14.Slot) {
             InventoryPackets.toClient((Item) metadata.getValue());
-        } else if (metadata.getMetaType() == MetaType1_14.BlockID) {
+        } else if (metadata.metaType() == MetaType1_14.BlockID) {
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
-        } else if (metadata.getMetaType() == MetaType1_14.PARTICLE) {
+        } else if (metadata.metaType() == MetaType1_14.PARTICLE) {
             rewriteParticle((Particle) metadata.getValue());
         }
 
         if (type == null) return;
 
         if (type.isOrHasParent(Entity1_16_2Types.MINECART_ABSTRACT)
-                && metadata.getId() == 10) {
+                && metadata.id() == 10) {
             // Convert to new block id
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
         }
 
         if (type.isOrHasParent(Entity1_16_2Types.ABSTRACT_PIGLIN)) {
-            if (metadata.getId() == 15) {
+            if (metadata.id() == 15) {
                 metadata.setId(16);
-            } else if (metadata.getId() == 16) {
+            } else if (metadata.id() == 16) {
                 metadata.setId(15);
             }
         }
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_16_2Types.getTypeFromId(type);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_16_2to1_16_1/packets/EntityPackets.java

@@ -25,18 +25,17 @@ import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.version.Types1_14;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.Protocol1_16_2To1_16_1;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.metadata.MetadataRewriter1_16_2To1_16_1;
-import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.storage.EntityTracker1_16_2;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.ClientboundPackets1_16;
 
 public class EntityPackets {
 
     public static void register(Protocol1_16_2To1_16_1 protocol) {
         MetadataRewriter1_16_2To1_16_1 metadataRewriter = protocol.get(MetadataRewriter1_16_2To1_16_1.class);
-        metadataRewriter.registerSpawnTrackerWithData(ClientboundPackets1_16.SPAWN_ENTITY, Entity1_16_2Types.FALLING_BLOCK);
+        metadataRewriter.registerTrackerWithData(ClientboundPackets1_16.SPAWN_ENTITY, Entity1_16_2Types.FALLING_BLOCK);
         metadataRewriter.registerTracker(ClientboundPackets1_16.SPAWN_MOB);
         metadataRewriter.registerTracker(ClientboundPackets1_16.SPAWN_PLAYER, Entity1_16_2Types.PLAYER);
         metadataRewriter.registerMetadataRewriter(ClientboundPackets1_16.ENTITY_METADATA, Types1_14.METADATA_LIST);
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_16.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_16.DESTROY_ENTITIES);
 
         protocol.registerClientbound(ClientboundPackets1_16.JOIN_GAME, new PacketRemapper() {
             @Override
@@ -65,7 +64,7 @@ public class EntityPackets {
                 map(Type.UNSIGNED_BYTE, Type.VAR_INT); // Max players
                 // ...
                 handler(wrapper -> {
-                    wrapper.user().get(EntityTracker1_16_2.class).addEntity(wrapper.get(Type.INT, 0), Entity1_16_2Types.PLAYER);
+                    wrapper.user().getEntityTracker(Protocol1_16_2To1_16_1.class).addEntity(wrapper.get(Type.INT, 0), Entity1_16_2Types.PLAYER);
                 });
             }
         });

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_16_2to1_16_1/storage/EntityTracker1_16_2.java

@@ -1,29 +0,0 @@
-/*
- * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
- * Copyright (C) 2016-2021 ViaVersion and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.storage;
-
-import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.minecraft.entities.Entity1_16_2Types;
-import com.viaversion.viaversion.data.EntityTracker;
-
-public class EntityTracker1_16_2 extends EntityTracker {
-
-    public EntityTracker1_16_2(UserConnection user) {
-        super(user, Entity1_16_2Types.PLAYER);
-    }
-}

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_16to1_15_2/Protocol1_16To1_15_2.java

@@ -23,10 +23,12 @@ import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_16Types;
 import com.viaversion.viaversion.api.protocol.AbstractProtocol;
 import com.viaversion.viaversion.api.protocol.packet.State;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.ServerboundPackets1_14;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.ClientboundPackets1_15;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.data.MappingData;
@@ -35,10 +37,9 @@ import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.metadata.Metadat
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.packets.EntityPackets;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.packets.InventoryPackets;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.packets.WorldPackets;
-import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.storage.EntityTracker1_16;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.storage.InventoryTracker1_16;
 import com.viaversion.viaversion.rewriter.ComponentRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 import com.viaversion.viaversion.rewriter.RegistryType;
 import com.viaversion.viaversion.rewriter.SoundRewriter;
 import com.viaversion.viaversion.rewriter.StatisticsRewriter;
@@ -62,16 +63,17 @@ public class Protocol1_16To1_15_2 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_16To1_15_2(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_16To1_15_2(this);
+        metadataRewriter.register();
 
         EntityPackets.register(this);
         WorldPackets.register(this);
         InventoryPackets.register(this);
 
-        tagRewriter = new TagRewriter(this, metadataRewriter::getNewEntityId);
+        tagRewriter = new TagRewriter(this, metadataRewriter::newEntityId);
         tagRewriter.register(ClientboundPackets1_15.TAGS, RegistryType.ENTITY);
 
-        new StatisticsRewriter(this, metadataRewriter::getNewEntityId).register(ClientboundPackets1_15.STATISTICS);
+        new StatisticsRewriter(this, metadataRewriter::newEntityId).register(ClientboundPackets1_15.STATISTICS);
 
         // Login Success
         registerClientbound(State.LOGIN, 0x02, 0x02, new PacketRemapper() {
@@ -271,7 +273,7 @@ public class Protocol1_16To1_15_2 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     public void init(UserConnection userConnection) {
-        userConnection.put(new EntityTracker1_16(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTrackerBase(userConnection, Entity1_16Types.PLAYER));
         userConnection.put(new InventoryTracker1_16(userConnection));
     }
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_16to1_15_2/metadata/MetadataRewriter1_16To1_15_2.java

@@ -27,50 +27,49 @@ import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_14;
 import com.viaversion.viaversion.api.type.types.Particle;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.Protocol1_16To1_15_2;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.packets.InventoryPackets;
-import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.storage.EntityTracker1_16;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 
-public class MetadataRewriter1_16To1_15_2 extends MetadataRewriter {
+public class MetadataRewriter1_16To1_15_2 extends EntityRewriter<Protocol1_16To1_15_2> {
 
     public MetadataRewriter1_16To1_15_2(Protocol1_16To1_15_2 protocol) {
-        super(protocol, EntityTracker1_16.class);
+        super(protocol);
-        mapType(Entity1_15Types.ZOMBIE_PIGMAN, Entity1_16Types.ZOMBIFIED_PIGLIN);
+        mapEntityType(Entity1_15Types.ZOMBIE_PIGMAN, Entity1_16Types.ZOMBIFIED_PIGLIN);
         mapTypes(Entity1_15Types.values(), Entity1_16Types.class);
     }
 
     @Override
     public void handleMetadata(int entityId, EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception {
-        if (metadata.getMetaType() == MetaType1_14.Slot) {
+        if (metadata.metaType() == MetaType1_14.Slot) {
             InventoryPackets.toClient((Item) metadata.getValue());
-        } else if (metadata.getMetaType() == MetaType1_14.BlockID) {
+        } else if (metadata.metaType() == MetaType1_14.BlockID) {
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
-        } else if (metadata.getMetaType() == MetaType1_14.PARTICLE) {
+        } else if (metadata.metaType() == MetaType1_14.PARTICLE) {
             rewriteParticle((Particle) metadata.getValue());
         }
 
         if (type == null) return;
 
         if (type.isOrHasParent(Entity1_16Types.MINECART_ABSTRACT)
-                && metadata.getId() == 10) {
+                && metadata.id() == 10) {
             // Convert to new block id
             int data = (int) metadata.getValue();
             metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
         }
 
         if (type.isOrHasParent(Entity1_16Types.ABSTRACT_ARROW)) {
-            if (metadata.getId() == 8) {
+            if (metadata.id() == 8) {
                 metadatas.remove(metadata);
-            } else if (metadata.getId() > 8) {
+            } else if (metadata.id() > 8) {
-                metadata.setId(metadata.getId() - 1);
+                metadata.setId(metadata.id() - 1);
             }
         }
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_16Types.getTypeFromId(type);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_16to1_15_2/packets/EntityPackets.java

@@ -35,7 +35,6 @@ import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.ClientboundPacke
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.Protocol1_16To1_15_2;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.ServerboundPackets1_16;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.metadata.MetadataRewriter1_16To1_15_2;
-import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.storage.EntityTracker1_16;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.storage.InventoryTracker1_16;
 
 import java.util.UUID;
@@ -152,7 +151,7 @@ public class EntityPackets {
             public void registerMap() {
                 handler(wrapper -> {
                     int entityId = wrapper.passthrough(Type.VAR_INT);
-                    wrapper.user().get(EntityTracker1_16.class).addEntity(entityId, Entity1_16Types.LIGHTNING_BOLT);
+                    wrapper.user().getEntityTracker(Protocol1_16To1_15_2.class).addEntity(entityId, Entity1_16Types.LIGHTNING_BOLT);
 
                     wrapper.write(Type.UUID, UUID.randomUUID()); // uuid
                     wrapper.write(Type.VAR_INT, Entity1_16Types.LIGHTNING_BOLT.getId()); // entity type
@@ -172,11 +171,11 @@ public class EntityPackets {
             }
         });
 
-        metadataRewriter.registerSpawnTrackerWithData(ClientboundPackets1_15.SPAWN_ENTITY, Entity1_16Types.FALLING_BLOCK);
+        metadataRewriter.registerTrackerWithData(ClientboundPackets1_15.SPAWN_ENTITY, Entity1_16Types.FALLING_BLOCK);
         metadataRewriter.registerTracker(ClientboundPackets1_15.SPAWN_MOB);
         metadataRewriter.registerTracker(ClientboundPackets1_15.SPAWN_PLAYER, Entity1_16Types.PLAYER);
         metadataRewriter.registerMetadataRewriter(ClientboundPackets1_15.ENTITY_METADATA, Types1_14.METADATA_LIST);
-        metadataRewriter.registerEntityDestroy(ClientboundPackets1_15.DESTROY_ENTITIES);
+        metadataRewriter.registerRemoveEntities(ClientboundPackets1_15.DESTROY_ENTITIES);
 
         protocol.registerClientbound(ClientboundPackets1_15.RESPAWN, new PacketRemapper() {
             @Override
@@ -209,7 +208,7 @@ public class EntityPackets {
                 map(Type.LONG); // Seed
                 map(Type.UNSIGNED_BYTE); // Max players
                 handler(wrapper -> {
-                    wrapper.user().get(EntityTracker1_16.class).addEntity(wrapper.get(Type.INT, 0), Entity1_16Types.PLAYER);
+                    wrapper.user().getEntityTracker(Protocol1_16To1_15_2.class).addEntity(wrapper.get(Type.INT, 0), Entity1_16Types.PLAYER);
 
                     final String type = wrapper.read(Type.STRING);// level type
                     wrapper.passthrough(Type.VAR_INT); // View distance

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_17to1_16_4/Protocol1_17To1_16_4.java

@@ -21,18 +21,19 @@ import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.data.MappingData;
 import com.viaversion.viaversion.api.data.MappingDataBase;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_17Types;
 import com.viaversion.viaversion.api.protocol.AbstractProtocol;
 import com.viaversion.viaversion.api.protocol.packet.ClientboundPacketType;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.ClientboundPackets1_16_2;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.ServerboundPackets1_16_2;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.metadata.MetadataRewriter1_17To1_16_4;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.packets.EntityPackets;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.packets.InventoryPackets;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.packets.WorldPackets;
-import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.storage.EntityTracker1_17;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 import com.viaversion.viaversion.rewriter.RegistryType;
 import com.viaversion.viaversion.rewriter.SoundRewriter;
 import com.viaversion.viaversion.rewriter.StatisticsRewriter;
@@ -50,7 +51,8 @@ public class Protocol1_17To1_16_4 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_17To1_16_4(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_17To1_16_4(this);
+        metadataRewriter.register();
 
         EntityPackets.register(this);
         InventoryPackets.register(this);
@@ -87,7 +89,7 @@ public class Protocol1_17To1_16_4 extends AbstractProtocol<ClientboundPackets1_1
             }
         });
 
-        new StatisticsRewriter(this, metadataRewriter::getNewEntityId).register(ClientboundPackets1_16_2.STATISTICS);
+        new StatisticsRewriter(this, metadataRewriter::newEntityId).register(ClientboundPackets1_16_2.STATISTICS);
 
         SoundRewriter soundRewriter = new SoundRewriter(this);
         soundRewriter.registerSound(ClientboundPackets1_16_2.SOUND);
@@ -237,7 +239,7 @@ public class Protocol1_17To1_16_4 extends AbstractProtocol<ClientboundPackets1_1
 
     @Override
     public void init(UserConnection user) {
-        user.put(new EntityTracker1_17(user));
+        user.addEntityTracker(this.getClass(), new EntityTrackerBase(user, Entity1_17Types.PLAYER));
     }
 
     @Override

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_17to1_16_4/metadata/MetadataRewriter1_17To1_16_4.java

@@ -17,73 +17,51 @@
  */
 package com.viaversion.viaversion.protocols.protocol1_17to1_16_4.metadata;
 
-import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.entities.Entity1_16_2Types;
 import com.viaversion.viaversion.api.minecraft.entities.Entity1_17Types;
 import com.viaversion.viaversion.api.minecraft.entities.EntityType;
-import com.viaversion.viaversion.api.minecraft.item.Item;
-import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
 import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_17;
-import com.viaversion.viaversion.api.type.types.Particle;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.Protocol1_17To1_16_4;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.packets.InventoryPackets;
-import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.storage.EntityTracker1_17;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
-import java.util.List;
+public class MetadataRewriter1_17To1_16_4 extends EntityRewriter {
-
-public class MetadataRewriter1_17To1_16_4 extends MetadataRewriter {
 
     public MetadataRewriter1_17To1_16_4(Protocol1_17To1_16_4 protocol) {
-        super(protocol, EntityTracker1_17.class);
+        super(protocol);
         mapTypes(Entity1_16_2Types.values(), Entity1_17Types.class);
     }
 
     @Override
-    public void handleMetadata(int entityId, EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception {
+    protected void registerRewrites() {
-        metadata.setMetaType(MetaType1_17.byId(metadata.getMetaType().getTypeID()));
+        filter().handler((event, meta) -> {
-        if (metadata.getMetaType() == MetaType1_17.Slot) {
+            meta.setMetaType(MetaType1_17.byId(meta.metaType().typeId()));
-            InventoryPackets.toClient((Item) metadata.getValue());
+
-        } else if (metadata.getMetaType() == MetaType1_17.BlockID) {
+            if (meta.metaType() == MetaType1_17.Pose) {
-            int data = (int) metadata.getValue();
+                int pose = meta.value();
-            metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
+                if (pose > 5) {
-        } else if (metadata.getMetaType() == MetaType1_17.PARTICLE) {
+                    // Added LONG_JUMP at 6
-            rewriteParticle((Particle) metadata.getValue());
+                    meta.setValue(pose + 1);
-        } else if (metadata.getMetaType() == MetaType1_17.Pose) {
+                }
-            int pose = metadata.getCastedValue();
-            if (pose > 5) {
-                // Added LONG_JUMP at 6
-                metadata.setValue(pose + 1);
             }
-        }
+        });
+        registerDumMetaTypeHandler(MetaType1_17.Slot, MetaType1_17.BlockID, MetaType1_17.PARTICLE, InventoryPackets::toClient);
 
-        if (type == null) return;
+        // Ticks frozen added with id 7
+        filter().filterFamily(Entity1_17Types.ENTITY).addIndex(7);
 
-        if (type.isOrHasParent(Entity1_17Types.ENTITY)) {
+        filter().filterFamily(Entity1_17Types.MINECART_ABSTRACT).index(11).handler((event, meta) -> {
-            if (metadata.getId() >= 7) {
-                metadata.setId(metadata.getId() + 1); // Ticks frozen added with id 7
-            }
-        }
-
-        if (type.isOrHasParent(Entity1_17Types.MINECART_ABSTRACT)
-                && metadata.getId() == 11) {
             // Convert to new block id
-            int data = (int) metadata.getValue();
+            int data = (int) meta.getValue();
-            metadata.setValue(protocol.getMappingData().getNewBlockStateId(data));
+            meta.setValue(protocol.getMappingData().getNewBlockStateId(data));
-        }
+        });
 
-        if (type == Entity1_17Types.SHULKER) {
+        // Attachment position removed
-            // Attachment position removed
+        filter().type(Entity1_17Types.SHULKER).removeIndex(16);
-            if (metadata.getId() == 16) {
-                metadatas.remove(metadata);
-            } else if (metadata.getId() > 16) {
-                metadata.setId(metadata.getId() - 1);
-            }
-        }
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_17Types.getTypeFromId(type);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_17to1_16_4/packets/EntityPackets.java

@@ -17,6 +17,7 @@
  */
 package com.viaversion.viaversion.protocols.protocol1_17to1_16_4.packets;
 
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
 import com.viaversion.viaversion.api.minecraft.entities.Entity1_17Types;
 import com.viaversion.viaversion.api.protocol.packet.ClientboundPacketType;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
@@ -24,18 +25,16 @@ import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.version.Types1_14;
 import com.viaversion.viaversion.api.type.types.version.Types1_17;
-import com.viaversion.viaversion.data.EntityTracker;
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.ClientboundPackets1_16_2;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.ClientboundPackets1_17;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.Protocol1_17To1_16_4;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.metadata.MetadataRewriter1_17To1_16_4;
-import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.storage.EntityTracker1_17;
 
 public class EntityPackets {
 
     public static void register(Protocol1_17To1_16_4 protocol) {
         MetadataRewriter1_17To1_16_4 metadataRewriter = protocol.get(MetadataRewriter1_17To1_16_4.class);
-        metadataRewriter.registerSpawnTrackerWithData(ClientboundPackets1_16_2.SPAWN_ENTITY, Entity1_17Types.FALLING_BLOCK);
+        metadataRewriter.registerTrackerWithData(ClientboundPackets1_16_2.SPAWN_ENTITY, Entity1_17Types.FALLING_BLOCK);
         metadataRewriter.registerTracker(ClientboundPackets1_16_2.SPAWN_MOB);
         metadataRewriter.registerTracker(ClientboundPackets1_16_2.SPAWN_PLAYER, Entity1_17Types.PLAYER);
         metadataRewriter.registerMetadataRewriter(ClientboundPackets1_16_2.ENTITY_METADATA, Types1_14.METADATA_LIST, Types1_17.METADATA_LIST);
@@ -47,7 +46,7 @@ public class EntityPackets {
                     int[] entityIds = wrapper.read(Type.VAR_INT_ARRAY_PRIMITIVE);
                     wrapper.cancel();
 
-                    EntityTracker entityTracker = wrapper.user().get(EntityTracker1_17.class);
+                    EntityTracker entityTracker = wrapper.user().getEntityTracker(Protocol1_17To1_16_4.class);
                     for (int entityId : entityIds) {
                         entityTracker.removeEntity(entityId);
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_17to1_16_4/packets/WorldPackets.java

@@ -35,7 +35,6 @@ import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.ClientboundPac
 import com.viaversion.viaversion.protocols.protocol1_16_2to1_16_1.types.Chunk1_16_2Type;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.ClientboundPackets1_17;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.Protocol1_17To1_16_4;
-import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.storage.EntityTracker1_17;
 import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.types.Chunk1_17Type;
 import com.viaversion.viaversion.rewriter.BlockRewriter;
 
@@ -188,7 +187,7 @@ public class WorldPackets {
                     addNewDimensionData(currentDimensionTag);
 
                     UserConnection user = wrapper.user();
-                    user.get(EntityTracker1_17.class).addEntity(wrapper.get(Type.INT, 0), Entity1_17Types.PLAYER);
+                    user.getEntityTracker(Protocol1_17To1_16_4.class).addEntity(wrapper.get(Type.INT, 0), Entity1_17Types.PLAYER);
                 });
             }
         });

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_17to1_16_4/storage/EntityTracker1_17.java

@@ -1,29 +0,0 @@
-/*
- * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
- * Copyright (C) 2016-2021 ViaVersion and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package com.viaversion.viaversion.protocols.protocol1_17to1_16_4.storage;
-
-import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.minecraft.entities.Entity1_17Types;
-import com.viaversion.viaversion.data.EntityTracker;
-
-public class EntityTracker1_17 extends EntityTracker {
-
-    public EntityTracker1_17(UserConnection user) {
-        super(user, Entity1_17Types.PLAYER);
-    }
-}

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/Protocol1_9To1_8.java

@@ -48,7 +48,7 @@ import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.CommandBlock
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.EntityTracker1_9;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.InventoryTracker;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.MovementTracker;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
 import com.viaversion.viaversion.util.GsonUtil;
 
 public class Protocol1_9To1_8 extends AbstractProtocol<ClientboundPackets1_8, ClientboundPackets1_9, ServerboundPackets1_8, ServerboundPackets1_9> {
@@ -108,7 +108,8 @@ public class Protocol1_9To1_8 extends AbstractProtocol<ClientboundPackets1_8, Cl
 
     @Override
     protected void registerPackets() {
-        MetadataRewriter metadataRewriter = new MetadataRewriter1_9To1_8(this);
+        EntityRewriter metadataRewriter = new MetadataRewriter1_9To1_8(this);
+        metadataRewriter.register();
 
         // Disconnect workaround (JSON!)
         registerClientbound(State.LOGIN, 0x00, 0x00, new PacketRemapper() {
@@ -146,7 +147,7 @@ public class Protocol1_9To1_8 extends AbstractProtocol<ClientboundPackets1_8, Cl
     @Override
     public void init(UserConnection userConnection) {
         // Entity tracker
-        userConnection.put(new EntityTracker1_9(userConnection));
+        userConnection.addEntityTracker(this.getClass(), new EntityTracker1_9(userConnection));
         // Chunk tracker
         userConnection.put(new ClientChunks(userConnection));
         // Movement tracker

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/chat/ChatRewriter.java

@@ -20,6 +20,7 @@ package com.viaversion.viaversion.protocols.protocol1_9to1_8.chat;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonObject;
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.EntityTracker1_9;
 
 public class ChatRewriter {
@@ -32,7 +33,8 @@ public class ChatRewriter {
     public static void toClient(JsonObject obj, UserConnection user) {
         //Check gamemode change
         if (obj.get("translate") != null && obj.get("translate").getAsString().equals("gameMode.changed")) {
-            String gameMode = user.get(EntityTracker1_9.class).getGameMode().getText();
+            EntityTracker1_9 tracker = user.getEntityTracker(Protocol1_9To1_8.class);
+            String gameMode = tracker.getGameMode().getText();
 
             JsonObject gameModeObject = new JsonObject();
             gameModeObject.addProperty("text", gameMode);

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/metadata/MetadataRewriter1_9To1_8.java

@@ -29,21 +29,20 @@ import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_8;
 import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_9;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.ItemRewriter;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
-import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.EntityTracker1_9;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
-import com.viaversion.viaversion.rewriter.MetadataRewriter;
 
 import java.util.List;
 import java.util.UUID;
 
-public class MetadataRewriter1_9To1_8 extends MetadataRewriter {
+public class MetadataRewriter1_9To1_8 extends EntityRewriter<Protocol1_9To1_8> {
 
     public MetadataRewriter1_9To1_8(Protocol1_9To1_8 protocol) {
-        super(protocol, EntityTracker1_9.class);
+        super(protocol);
     }
 
     @Override
     protected void handleMetadata(int entityId, EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception {
-        MetaIndex metaIndex = MetaIndex.searchIndex(type, metadata.getId());
+        MetaIndex metaIndex = MetaIndex.searchIndex(type, metadata.id());
         if (metaIndex == null) {
             throw new Exception("Could not find valid metadata");
         }
@@ -139,12 +138,12 @@ public class MetadataRewriter1_9To1_8 extends MetadataRewriter {
     }
 
     @Override
-    protected EntityType getTypeFromId(int type) {
+    protected EntityType typeFromId(int type) {
         return Entity1_10Types.getTypeFromId(type, false);
     }
 
     @Override
-    protected EntityType getObjectTypeFromId(int type) {
+    protected EntityType objectTypeFromId(int type) {
         return Entity1_10Types.getTypeFromId(type, true);
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/packets/EntityPackets.java

@@ -64,7 +64,7 @@ public class EntityPackets {
                 map(Type.BOOLEAN, new ValueTransformer<Boolean, Void>(Type.NOTHING) {
                     @Override
                     public Void transform(PacketWrapper wrapper, Boolean inputValue) throws Exception {
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         if (!inputValue) {
                             int passenger = wrapper.get(Type.INT, 0);
                             int vehicle = wrapper.get(Type.INT, 1);
@@ -108,7 +108,7 @@ public class EntityPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
                         if (Via.getConfig().isHologramPatch()) {
-                            EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                            EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                             if (tracker.getKnownHolograms().contains(entityID)) {
                                 Double newValue = wrapper.get(Type.DOUBLE, 1);
                                 newValue += (Via.getConfig().getHologramYOffset());
@@ -158,7 +158,7 @@ public class EntityPackets {
                     @Override
                     public Integer transform(PacketWrapper wrapper, Short slot) throws Exception {
                         int entityId = wrapper.get(Type.VAR_INT, 0);
-                        int receiverId = wrapper.user().get(EntityTracker1_9.class).getClientEntityId();
+                        int receiverId = wrapper.user().getEntityTracker(Protocol1_9To1_8.class).clientEntityId();
                         // Normally, 0 = hand and 1-4 = armor
                         // ... but if the sent id is equal to the receiver's id, 0-3 will instead mark the armor slots
                         // (In 1.9+, every client treats the received the same: 0=hand, 1=offhand, 2-5=armor)
@@ -181,7 +181,7 @@ public class EntityPackets {
                 handler(new PacketHandler() {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
-                        EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         int entityID = wrapper.get(Type.VAR_INT, 0);
                         Item stack = wrapper.get(Type.ITEM, 0);
 
@@ -207,7 +207,7 @@ public class EntityPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         List<Metadata> metadataList = wrapper.get(Types1_9.METADATA_LIST, 0);
                         int entityId = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         if (tracker.hasEntity(entityId)) {
                             protocol.get(MetadataRewriter1_9To1_8.class).handleMetadata(entityId, metadataList, wrapper.user());
                         } else {
@@ -224,7 +224,7 @@ public class EntityPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         List<Metadata> metadataList = wrapper.get(Types1_9.METADATA_LIST, 0);
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.handleMetadata(entityID, metadataList);
                     }
                 });
@@ -288,7 +288,9 @@ public class EntityPackets {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
                         if (!Via.getConfig().isMinimizeCooldown()) return;
-                        if (wrapper.get(Type.VAR_INT, 0) != wrapper.user().get(EntityTracker1_9.class).getProvidedEntityId()) {
+
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+                        if (wrapper.get(Type.VAR_INT, 0) != tracker.getProvidedEntityId()) {
                             return;
                         }
                         int propertiesToRead = wrapper.read(Type.INT);

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/packets/InventoryPackets.java

@@ -121,7 +121,7 @@ public class InventoryPackets {
                         // Check if it is the inventory of the player
                         if (showShieldWhenSwordInHand) {
                             InventoryTracker inventoryTracker = wrapper.user().get(InventoryTracker.class);
-                            EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                            EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
 
                             short slotID = wrapper.get(Type.SHORT, 0);
                             short windowId = wrapper.get(Type.BYTE, 0);
@@ -168,7 +168,7 @@ public class InventoryPackets {
                         Short windowId = wrapper.get(Type.UNSIGNED_BYTE, 0);
 
                         InventoryTracker inventoryTracker = wrapper.user().get(InventoryTracker.class);
-                        EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
 
                         boolean showShieldWhenSwordInHand = Via.getConfig().isShowShieldWhenSwordInHand()
                                 && Via.getConfig().isShieldBlocking();
@@ -266,7 +266,7 @@ public class InventoryPackets {
 
                         if (showShieldWhenSwordInHand) {
                             InventoryTracker inventoryTracker = wrapper.user().get(InventoryTracker.class);
-                            EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                            EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                             short slotID = wrapper.get(Type.SHORT, 0);
 
                             // Update item in slot
@@ -401,7 +401,7 @@ public class InventoryPackets {
                         boolean showShieldWhenSwordInHand = Via.getConfig().isShowShieldWhenSwordInHand()
                                 && Via.getConfig().isShieldBlocking();
 
-                        EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         if (entityTracker.isBlocking()) {
                             entityTracker.setBlocking(false);
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/packets/PlayerPackets.java

@@ -19,6 +19,7 @@ package com.viaversion.viaversion.protocols.protocol1_9to1_8.packets;
 
 import com.google.gson.JsonObject;
 import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
 import com.viaversion.viaversion.api.minecraft.entities.Entity1_10Types;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
@@ -139,7 +140,7 @@ public class PlayerPackets {
 
                         if (mode == 0 || mode == 3 || mode == 4) {
                             String[] players = wrapper.passthrough(Type.STRING_ARRAY); // Players
-                            final EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                            final EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                             String myName = wrapper.user().getProtocolInfo().getUsername();
                             String teamName = wrapper.get(Type.STRING, 0);
                             for (String player : players) {
@@ -161,7 +162,7 @@ public class PlayerPackets {
                         }
 
                         if (mode == 1) { // Remove team
-                            final EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                            final EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                             String teamName = wrapper.get(Type.STRING, 0);
                             if (entityTracker.isAutoTeam()
                                     && teamName.equals(entityTracker.getCurrentTeam())) {
@@ -187,7 +188,7 @@ public class PlayerPackets {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int entityId = wrapper.get(Type.INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.addEntity(entityId, Entity1_10Types.EntityType.PLAYER);
                         tracker.setClientEntityId(entityId);
                     }
@@ -202,7 +203,7 @@ public class PlayerPackets {
                 handler(new PacketHandler() {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.setGameMode(GameMode.getById(wrapper.get(Type.UNSIGNED_BYTE, 0))); //Set player gamemode
                     }
                 });
@@ -221,7 +222,7 @@ public class PlayerPackets {
                 handler(new PacketHandler() {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
-                        EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         if (Via.getConfig().isAutoTeam()) {
                             entityTracker.setAutoTeam(true);
                             // Workaround for packet order issue
@@ -367,7 +368,8 @@ public class PlayerPackets {
                         cc.getLoadedChunks().clear();
 
                         int gamemode = wrapper.get(Type.UNSIGNED_BYTE, 0);
-                        wrapper.user().get(EntityTracker1_9.class).setGameMode(GameMode.getById(gamemode));
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+                        tracker.setGameMode(GameMode.getById(gamemode));
                     }
                 });
 
@@ -394,7 +396,8 @@ public class PlayerPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         if (wrapper.get(Type.UNSIGNED_BYTE, 0) == 3) { //Change gamemode
                             int gamemode = wrapper.get(Type.FLOAT, 0).intValue();
-                            wrapper.user().get(EntityTracker1_9.class).setGameMode(GameMode.getById(gamemode));
+                            EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
+                            tracker.setGameMode(GameMode.getById(gamemode));
                         }
                     }
                 });
@@ -496,7 +499,7 @@ public class PlayerPackets {
                         int action = wrapper.get(Type.VAR_INT, 0);
                         if (action == 2) {
                             // cancel any blocking >.>
-                            EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                            EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                             if (tracker.isBlocking()) {
                                 if (!Via.getConfig().isShowShieldWhenSwordInHand()) {
                                     tracker.setSecondHand(null);

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/packets/SpawnPackets.java

@@ -57,7 +57,7 @@ public class SpawnPackets {
                     @Override
                     public void write(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         wrapper.write(Type.UUID, tracker.getEntityUUID(entityID)); // 1 - UUID
                     }
                 });
@@ -69,7 +69,7 @@ public class SpawnPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
                         int typeID = wrapper.get(Type.BYTE, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.addEntity(entityID, Entity1_10Types.getTypeFromId(typeID, true));
                         tracker.sendMetadataBuffer(entityID);
                     }
@@ -143,7 +143,7 @@ public class SpawnPackets {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.addEntity(entityID, Entity1_10Types.EntityType.EXPERIENCE_ORB);
                         tracker.sendMetadataBuffer(entityID);
                     }
@@ -168,7 +168,7 @@ public class SpawnPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         // Currently only lightning uses this
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.addEntity(entityID, Entity1_10Types.EntityType.LIGHTNING);
                         tracker.sendMetadataBuffer(entityID);
                     }
@@ -189,7 +189,7 @@ public class SpawnPackets {
                     @Override
                     public void write(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         wrapper.write(Type.UUID, tracker.getEntityUUID(entityID)); // 1 - UUID
                     }
                 });
@@ -201,7 +201,7 @@ public class SpawnPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
                         int typeID = wrapper.get(Type.UNSIGNED_BYTE, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.addEntity(entityID, Entity1_10Types.getTypeFromId(typeID, false));
                         tracker.sendMetadataBuffer(entityID);
                     }
@@ -225,7 +225,7 @@ public class SpawnPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         List<Metadata> metadataList = wrapper.get(Types1_9.METADATA_LIST, 0);
                         int entityId = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         if (tracker.hasEntity(entityId)) {
                             protocol.get(MetadataRewriter1_9To1_8.class).handleMetadata(entityId, metadataList, wrapper.user());
                         } else {
@@ -240,7 +240,7 @@ public class SpawnPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         List<Metadata> metadataList = wrapper.get(Types1_9.METADATA_LIST, 0);
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.handleMetadata(entityID, metadataList);
                     }
                 });
@@ -257,7 +257,7 @@ public class SpawnPackets {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.addEntity(entityID, Entity1_10Types.EntityType.PAINTING);
                         tracker.sendMetadataBuffer(entityID);
                     }
@@ -266,7 +266,7 @@ public class SpawnPackets {
                     @Override
                     public void write(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         wrapper.write(Type.UUID, tracker.getEntityUUID(entityID)); // 1 - UUID
                     }
                 });
@@ -288,7 +288,7 @@ public class SpawnPackets {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.addEntity(entityID, Entity1_10Types.EntityType.PLAYER);
                         tracker.sendMetadataBuffer(entityID);
                     }
@@ -326,7 +326,7 @@ public class SpawnPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         List<Metadata> metadataList = wrapper.get(Types1_9.METADATA_LIST, 0);
                         int entityId = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         if (tracker.hasEntity(entityId)) {
                             protocol.get(MetadataRewriter1_9To1_8.class).handleMetadata(entityId, metadataList, wrapper.user());
                         } else {
@@ -342,7 +342,7 @@ public class SpawnPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         List<Metadata> metadataList = wrapper.get(Types1_9.METADATA_LIST, 0);
                         int entityID = wrapper.get(Type.VAR_INT, 0);
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.handleMetadata(entityID, metadataList);
                     }
                 });
@@ -361,7 +361,7 @@ public class SpawnPackets {
                         int[] entities = wrapper.get(Type.VAR_INT_ARRAY_PRIMITIVE, 0);
                         for (int entity : entities) {
                             // EntityTracker
-                            wrapper.user().get(EntityTracker1_9.class).removeEntity(entity);
+                            wrapper.user().getEntityTracker(Protocol1_9To1_8.class).removeEntity(entity);
                         }
                     }
                 });

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/packets/WorldPackets.java

@@ -113,7 +113,7 @@ public class WorldPackets {
                         wrapper.set(Type.STRING, 0, newname);
                         wrapper.write(Type.VAR_INT, catid); // Write Category ID
                         if (effect != null && effect.isBreaksound()) {
-                            EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                            EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                             int x = wrapper.passthrough(Type.INT); //Position X
                             int y = wrapper.passthrough(Type.INT); //Position Y
                             int z = wrapper.passthrough(Type.INT); //Position Z
@@ -278,7 +278,7 @@ public class WorldPackets {
                     public void handle(PacketWrapper wrapper) throws Exception {
                         int status = wrapper.get(Type.UNSIGNED_BYTE, 0);
                         if (status == 5 || status == 4 || status == 3) {
-                            EntityTracker1_9 entityTracker = wrapper.user().get(EntityTracker1_9.class);
+                            EntityTracker1_9 entityTracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                             if (entityTracker.isBlocking()) {
                                 entityTracker.setBlocking(false);
                                 if (!Via.getConfig().isShowShieldWhenSwordInHand()) {
@@ -308,7 +308,7 @@ public class WorldPackets {
                         Item item = Protocol1_9To1_8.getHandItem(wrapper.user());
                         // Blocking patch
                         if (Via.getConfig().isShieldBlocking()) {
-                            EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                            EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
 
                             // Check if the shield is already there or if we have to give it here
                             boolean showShieldWhenSwordInHand = Via.getConfig().isShowShieldWhenSwordInHand();
@@ -412,7 +412,7 @@ public class WorldPackets {
                                 x++;
                                 break;
                         }
-                        EntityTracker1_9 tracker = wrapper.user().get(EntityTracker1_9.class);
+                        EntityTracker1_9 tracker = wrapper.user().getEntityTracker(Protocol1_9To1_8.class);
                         tracker.addBlockInteraction(new Position(x, y, z));
                     }
                 });

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/providers/CommandBlockProvider.java

@@ -59,7 +59,8 @@ public class CommandBlockProvider implements Provider {
             return;
         PacketWrapper wrapper = PacketWrapper.create(0x1B, null, user); // Entity status
 
-        wrapper.write(Type.INT, user.get(EntityTracker1_9.class).getProvidedEntityId()); // Entity ID
+        EntityTracker1_9 tracker = user.getEntityTracker(Protocol1_9To1_8.class);
+        wrapper.write(Type.INT, tracker.getProvidedEntityId()); // Entity ID
         wrapper.write(Type.BYTE, (byte) 26); // Hardcoded op permission level
 
         wrapper.send(Protocol1_9To1_8.class);

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/providers/EntityIdProvider.java

@@ -19,11 +19,11 @@ package com.viaversion.viaversion.protocols.protocol1_9to1_8.providers;
 
 import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.platform.providers.Provider;
-import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.EntityTracker1_9;
+import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
 
 public class EntityIdProvider implements Provider {
 
     public int getEntityId(UserConnection user) throws Exception {
-        return user.get(EntityTracker1_9.class).getClientEntityId();
+        return user.getEntityTracker(Protocol1_9To1_8.class).clientEntityId();
     }
 }

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/storage/EntityTracker1_9.java

@@ -20,10 +20,10 @@ package com.viaversion.viaversion.protocols.protocol1_9to1_8.storage;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.collect.Sets;
 import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.legacy.bossbar.BossBar;
 import com.viaversion.viaversion.api.legacy.bossbar.BossColor;
 import com.viaversion.viaversion.api.legacy.bossbar.BossStyle;
-import com.viaversion.viaversion.api.connection.UserConnection;
 import com.viaversion.viaversion.api.minecraft.Position;
 import com.viaversion.viaversion.api.minecraft.entities.Entity1_10Types.EntityType;
 import com.viaversion.viaversion.api.minecraft.item.Item;
@@ -32,7 +32,7 @@ import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_9;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.version.Types1_9;
-import com.viaversion.viaversion.data.EntityTracker;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.chat.GameMode;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.metadata.MetadataRewriter1_9To1_8;
@@ -48,7 +48,7 @@ import java.util.UUID;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 
-public class EntityTracker1_9 extends EntityTracker {
+public class EntityTracker1_9 extends EntityTrackerBase {
     private final Map<Integer, UUID> uuidMap = new ConcurrentHashMap<>();
     private final Map<Integer, List<Metadata>> metadataBuffer = new ConcurrentHashMap<>();
     private final Map<Integer, Integer> vehicleMap = new ConcurrentHashMap<>();
@@ -84,11 +84,11 @@ public class EntityTracker1_9 extends EntityTracker {
     }
 
     public void setSecondHand(Item item) {
-        setSecondHand(getClientEntityId(), item);
+        setSecondHand(clientEntityId(), item);
     }
 
     public void setSecondHand(int entityID, Item item) {
-        PacketWrapper wrapper = PacketWrapper.create(0x3C, null, getUser());
+        PacketWrapper wrapper = PacketWrapper.create(0x3C, null, user());
         wrapper.write(Type.VAR_INT, entityID);
         wrapper.write(Type.VAR_INT, 1); // slot
         wrapper.write(Type.ITEM, this.itemInSecondHand = item);
@@ -124,7 +124,7 @@ public class EntityTracker1_9 extends EntityTracker {
      * @return player has a sword in the main hand
      */
     public boolean hasSwordInHand() {
-        InventoryTracker inventoryTracker = getUser().get(InventoryTracker.class);
+        InventoryTracker inventoryTracker = user().get(InventoryTracker.class);
 
         // Get item in new selected slot
         int inventorySlot = this.heldItemSlot + 36; // Hotbar slot index to inventory slot
@@ -147,7 +147,7 @@ public class EntityTracker1_9 extends EntityTracker {
         if (bar != null) {
             bar.hide();
             // Send to provider
-            Via.getManager().getProviders().get(BossBarProvider.class).handleRemove(getUser(), bar.getId());
+            Via.getManager().getProviders().get(BossBarProvider.class).handleRemove(user(), bar.getId());
         }
     }
 
@@ -160,7 +160,7 @@ public class EntityTracker1_9 extends EntityTracker {
     }
 
     public void handleMetadata(int entityId, List<Metadata> metadataList) {
-        com.viaversion.viaversion.api.minecraft.entities.EntityType type = getEntity(entityId);
+        com.viaversion.viaversion.api.minecraft.entities.EntityType type = entityType(entityId);
         if (type == null) {
             return;
         }
@@ -168,14 +168,14 @@ public class EntityTracker1_9 extends EntityTracker {
         for (Metadata metadata : new ArrayList<>(metadataList)) {
             // Fix: wither (crash fix)
             if (type == EntityType.WITHER) {
-                if (metadata.getId() == 10) {
+                if (metadata.id() == 10) {
                     metadataList.remove(metadata);
                     //metadataList.add(new Metadata(10, NewType.Byte.getTypeID(), Type.BYTE, 0));
                 }
             }
             // Fix: enderdragon (crash fix)
             if (type == EntityType.ENDER_DRAGON) {
-                if (metadata.getId() == 11) {
+                if (metadata.id() == 11) {
                     metadataList.remove(metadata);
                     //   metadataList.add(new Metadata(11, NewType.Byte.getTypeID(), Type.VAR_INT, 0));
                 }
@@ -190,12 +190,12 @@ public class EntityTracker1_9 extends EntityTracker {
             //ECHOPET Patch
             if (type == EntityType.HORSE) {
                 // Wrong metadata value from EchoPet, patch since it's discontinued. (https://github.com/DSH105/EchoPet/blob/06947a8b08ce40be9a518c2982af494b3b99d140/modules/API/src/main/java/com/dsh105/echopet/compat/api/entity/HorseArmour.java#L22)
-                if (metadata.getId() == 16 && (int) metadata.getValue() == Integer.MIN_VALUE)
+                if (metadata.id() == 16 && (int) metadata.getValue() == Integer.MIN_VALUE)
                     metadata.setValue(0);
             }
 
             if (type == EntityType.PLAYER) {
-                if (metadata.getId() == 0) {
+                if (metadata.id() == 0) {
                     // Byte
                     byte data = (byte) metadata.getValue();
                     if (entityId != getProvidedEntityId() && Via.getConfig().isShieldBlocking()) {
@@ -211,7 +211,7 @@ public class EntityTracker1_9 extends EntityTracker {
                         }
                     }
                 }
-                if (metadata.getId() == 12 && Via.getConfig().isLeftHandedHandling()) { // Player model
+                if (metadata.id() == 12 && Via.getConfig().isLeftHandedHandling()) { // Player model
                     metadataList.add(new Metadata(
                             13, // Main hand
                             MetaType1_9.Byte,
@@ -220,7 +220,7 @@ public class EntityTracker1_9 extends EntityTracker {
                 }
             }
             if (type == EntityType.ARMOR_STAND && Via.getConfig().isHologramPatch()) {
-                if (metadata.getId() == 0 && getMetaByIndex(metadataList, 10) != null) {
+                if (metadata.id() == 0 && getMetaByIndex(metadataList, 10) != null) {
                     Metadata meta = getMetaByIndex(metadataList, 10); //Only happens if the armorstand is small
                     byte data = (byte) metadata.getValue();
                     // Check invisible | Check small | Check if custom name is empty | Check if custom name visible is true
@@ -233,7 +233,7 @@ public class EntityTracker1_9 extends EntityTracker {
                             knownHolograms.add(entityId);
                             try {
                                 // Send movement
-                                PacketWrapper wrapper = PacketWrapper.create(0x25, null, getUser());
+                                PacketWrapper wrapper = PacketWrapper.create(0x25, null, user());
                                 wrapper.write(Type.VAR_INT, entityId);
                                 wrapper.write(Type.SHORT, (short) 0);
                                 wrapper.write(Type.SHORT, (short) (128D * (Via.getConfig().getHologramYOffset() * 32D)));
@@ -249,22 +249,22 @@ public class EntityTracker1_9 extends EntityTracker {
             // Boss bar
             if (Via.getConfig().isBossbarPatch()) {
                 if (type == EntityType.ENDER_DRAGON || type == EntityType.WITHER) {
-                    if (metadata.getId() == 2) {
+                    if (metadata.id() == 2) {
                         BossBar bar = bossBarMap.get(entityId);
                         String title = (String) metadata.getValue();
                         title = title.isEmpty() ? (type == EntityType.ENDER_DRAGON ? "Ender Dragon" : "Wither") : title;
                         if (bar == null) {
                             bar = Via.getAPI().legacyAPI().createLegacyBossBar(title, BossColor.PINK, BossStyle.SOLID);
                             bossBarMap.put(entityId, bar);
-                            bar.addConnection(getUser());
+                            bar.addConnection(user());
                             bar.show();
 
                             // Send to provider
-                            Via.getManager().getProviders().get(BossBarProvider.class).handleAdd(getUser(), bar.getId());
+                            Via.getManager().getProviders().get(BossBarProvider.class).handleAdd(user(), bar.getId());
                         } else {
                             bar.setTitle(title);
                         }
-                    } else if (metadata.getId() == 6 && !Via.getConfig().isBossbarAntiflicker()) { // If anti flicker is enabled, don't update health
+                    } else if (metadata.id() == 6 && !Via.getConfig().isBossbarAntiflicker()) { // If anti flicker is enabled, don't update health
                         BossBar bar = bossBarMap.get(entityId);
                         // Make health range between 0 and 1
                         float maxHealth = type == EntityType.ENDER_DRAGON ? 200.0f : 300.0f;
@@ -273,10 +273,10 @@ public class EntityTracker1_9 extends EntityTracker {
                             String title = type == EntityType.ENDER_DRAGON ? "Ender Dragon" : "Wither";
                             bar = Via.getAPI().legacyAPI().createLegacyBossBar(title, health, BossColor.PINK, BossStyle.SOLID);
                             bossBarMap.put(entityId, bar);
-                            bar.addConnection(getUser());
+                            bar.addConnection(user());
                             bar.show();
                             // Send to provider
-                            Via.getManager().getProviders().get(BossBarProvider.class).handleAdd(getUser(), bar.getId());
+                            Via.getManager().getProviders().get(BossBarProvider.class).handleAdd(user(), bar.getId());
                         } else {
                             bar.setHealth(health);
                         }
@@ -288,14 +288,14 @@ public class EntityTracker1_9 extends EntityTracker {
 
     public Metadata getMetaByIndex(List<Metadata> list, int index) {
         for (Metadata meta : list)
-            if (index == meta.getId()) {
+            if (index == meta.id()) {
                 return meta;
             }
         return null;
     }
 
     public void sendTeamPacket(boolean add, boolean now) {
-        PacketWrapper wrapper = PacketWrapper.create(0x41, null, getUser());
+        PacketWrapper wrapper = PacketWrapper.create(0x41, null, user());
         wrapper.write(Type.STRING, "viaversion"); // Use viaversion as name
         if (add) {
             // add
@@ -311,7 +311,7 @@ public class EntityTracker1_9 extends EntityTracker {
             } else {
                 wrapper.write(Type.BYTE, (byte) 3);
             }
-            wrapper.write(Type.STRING_ARRAY, new String[]{getUser().getProtocolInfo().getUsername()});
+            wrapper.write(Type.STRING_ARRAY, new String[]{user().getProtocolInfo().getUsername()});
         } else {
             wrapper.write(Type.BYTE, (byte) 1); // remove team
         }
@@ -335,11 +335,11 @@ public class EntityTracker1_9 extends EntityTracker {
     public void sendMetadataBuffer(int entityId) {
         List<Metadata> metadataList = metadataBuffer.get(entityId);
         if (metadataList != null) {
-            PacketWrapper wrapper = PacketWrapper.create(0x39, null, getUser());
+            PacketWrapper wrapper = PacketWrapper.create(0x39, null, user());
             wrapper.write(Type.VAR_INT, entityId);
             wrapper.write(Types1_9.METADATA_LIST, metadataList);
             Via.getManager().getProtocolManager().getProtocol(Protocol1_9To1_8.class).get(MetadataRewriter1_9To1_8.class)
-                    .handleMetadata(entityId, metadataList, getUser());
+                    .handleMetadata(entityId, metadataList, user());
             handleMetadata(entityId, metadataList);
             if (!metadataList.isEmpty()) {
                 try {
@@ -354,9 +354,9 @@ public class EntityTracker1_9 extends EntityTracker {
 
     public int getProvidedEntityId() {
         try {
-            return Via.getManager().getProviders().get(EntityIdProvider.class).getEntityId(getUser());
+            return Via.getManager().getProviders().get(EntityIdProvider.class).getEntityId(user());
         } catch (Exception e) {
-            return getClientEntityId();
+            return clientEntityId();
         }
     }
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/storage/InventoryTracker.java

@@ -19,6 +19,7 @@ package com.viaversion.viaversion.protocols.protocol1_9to1_8.storage;
 
 import com.viaversion.viaversion.api.connection.StoredObject;
 import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -83,7 +84,7 @@ public class InventoryTracker extends StoredObject {
      * @param button    The button to use in the click
      */
     public void handleWindowClick(short windowId, byte mode, short hoverSlot, byte button) {
-        EntityTracker1_9 entityTracker = getUser().get(EntityTracker1_9.class);
+        EntityTracker1_9 entityTracker = getUser().getEntityTracker(Protocol1_9To1_8.class);
 
         // Skip inventory background clicks
         if (hoverSlot == -1) {

common/src/main/java/com/viaversion/viaversion/rewriter/EntityRewriter.java

@@ -0,0 +1,521 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2021 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viaversion.rewriter;
+
+import com.github.steveice10.opennbt.tag.builtin.CompoundTag;
+import com.github.steveice10.opennbt.tag.builtin.IntTag;
+import com.github.steveice10.opennbt.tag.builtin.Tag;
+import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.data.ParticleMappings;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import com.viaversion.viaversion.api.minecraft.metadata.MetaType;
+import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
+import com.viaversion.viaversion.api.protocol.Protocol;
+import com.viaversion.viaversion.api.protocol.packet.ClientboundPacketType;
+import com.viaversion.viaversion.api.protocol.remapper.PacketHandler;
+import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.types.Particle;
+import com.viaversion.viaversion.rewriter.meta.MetaFilter;
+import com.viaversion.viaversion.rewriter.meta.MetaHandlerEvent;
+import com.viaversion.viaversion.rewriter.meta.MetaHandlerEventImpl;
+import it.unimi.dsi.fastutil.ints.Int2IntMap;
+import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+public abstract class EntityRewriter<T extends Protocol> extends RewriterBase<T> {
+    private static final Metadata[] EMPTY_ARRAY = new Metadata[0];
+    protected final List<MetaFilter> metadataFilters = new ArrayList<>();
+    protected final boolean trackMappedType;
+    protected Int2IntMap typeMappings;
+
+    protected EntityRewriter(T protocol) {
+        this(protocol, true);
+    }
+
+    /**
+     * Creates a new entity rewriter instance.
+     *
+     * @param protocol        protocol
+     * @param trackMappedType whether the mapped or unmapped entity type should be tracked
+     */
+    protected EntityRewriter(T protocol, boolean trackMappedType) {
+        super(protocol);
+        this.trackMappedType = trackMappedType;
+        protocol.put(this);
+    }
+
+    /**
+     * Returns a meta filter builder.
+     * <p>
+     * Calling {@link MetaFilter.Builder#register()} will automatically register the filter on this rewriter.
+     * Don't forget to call {@link MetaFilter.Builder#register()}.
+     *
+     * @return meta filter builder
+     */
+    public MetaFilter.Builder filter() {
+        return new MetaFilter.Builder(this);
+    }
+
+    /**
+     * Registers a metadata filter.
+     * Note that {@link MetaFilter.Builder#register()} already calls this method.
+     *
+     * @param filter filter to register
+     * @throws IllegalArgumentException if the filter is already registered
+     */
+    public void registerFilter(MetaFilter filter) {
+        Preconditions.checkArgument(!metadataFilters.contains(filter));
+        metadataFilters.add(filter);
+    }
+
+    /**
+     * Handles and transforms metadata of an entity.
+     *
+     * @param entityId     entity id
+     * @param metadataList full, mutable list of metadata
+     * @param connection   user connection
+     */
+    public void handleMetadata(int entityId, List<Metadata> metadataList, UserConnection connection) {
+        EntityType type = tracker(connection).entityType(entityId);
+        int i = 0; // Count index for fast removal
+        for (Metadata metadata : metadataList.toArray(EMPTY_ARRAY)) { // Copy the list to allow mutation
+            // Call handlers implementing the old handleMetadata
+            if (!callOldMetaHandler(entityId, type, metadata, metadataList, connection)) {
+                metadataList.remove(i--);
+                continue;
+            }
+
+            for (MetaFilter filter : metadataFilters) {
+                if (filter.isFiltered(type, metadata)) {
+                    MetaHandlerEvent event = new MetaHandlerEventImpl(connection, type, entityId, metadata.id(), metadata, metadataList);
+                    try {
+                        filter.handler().handle(event, metadata);
+                    } catch (Exception e) {
+                        logException(e, type, metadataList, metadata);
+                        metadataList.remove(i--);
+                        break;
+                    }
+
+                    if (event.cancelled()) {
+                        // Remove meta, decrease list index counter, and break current filter loop
+                        metadataList.remove(i--);
+                        break;
+                    }
+
+                    Preconditions.checkArgument(event.index() == event.meta().id(), "Meta event id desync: Calls to meta().setId() are illegal");
+                    if (event.extraMeta() != null) {
+                        // Add newly created meta
+                        metadataList.addAll(event.extraMeta());
+                        event.clearExtraMeta();
+                    }
+                }
+            }
+            i++;
+        }
+    }
+
+    @Deprecated
+    private boolean callOldMetaHandler(int entityId, EntityType type, Metadata metadata, List<Metadata> metadataList, UserConnection connection) {
+        try {
+            handleMetadata(entityId, type, metadata, metadataList, connection);
+            return true;
+        } catch (Exception e) {
+            logException(e, type, metadataList, metadata);
+            return false;
+        }
+    }
+
+    /**
+     * To be overridden to handle metadata.
+     *
+     * @param entityId   entity id
+     * @param type       entity type, or null if not tracked
+     * @param metadata   current metadata
+     * @param metadatas  full, mutable list of metadata
+     * @param connection user connection
+     * @deprecated use {@link #filter()}
+     */
+    @Deprecated
+    protected void handleMetadata(int entityId, @Nullable EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception {
+    }
+
+    /**
+     * Returns the entity type from the given (mapped) type id.
+     *
+     * @param type mapped type id
+     * @return entity type
+     */
+    protected abstract EntityType typeFromId(int type);
+
+    /**
+     * Returns the entity type from the given id.
+     * From 1.14 and onwards, this is the same exact value as {@link #typeFromId(int)}.
+     *
+     * @param type entity type id
+     * @return EntityType from id
+     */
+    protected EntityType objectTypeFromId(int type) {
+        return typeFromId(type);
+    }
+
+    /**
+     * Returns the mapped entitiy (or the same if it has not changed).
+     *
+     * @param oldId old entity id
+     * @return mapped entity id
+     */
+    public int newEntityId(int oldId) {
+        return typeMappings != null ? typeMappings.getOrDefault(oldId, oldId) : oldId;
+    }
+
+    /**
+     * Maps an entity type.
+     *
+     * @param type       entity type
+     * @param mappedType mapped entity type
+     * @throws IllegalArgumentException if the types share the same implementing class
+     */
+    public void mapEntityType(EntityType type, EntityType mappedType) {
+        Preconditions.checkArgument(type.getClass() != mappedType.getClass(), "EntityTypes should not be of the same class/enum");
+        mapEntityType(type.getId(), mappedType.getId());
+    }
+
+    protected void mapEntityType(int id, int mappedId) {
+        if (typeMappings == null) {
+            typeMappings = new Int2IntOpenHashMap();
+            typeMappings.defaultReturnValue(-1);
+        }
+        typeMappings.put(id, mappedId);
+    }
+
+    /**
+     * Maps entity ids based on the enum constant's names.
+     *
+     * @param oldTypes     entity types of the higher version
+     * @param newTypeClass entity types enum class of the lower version
+     * @param <E>          new enum entity type
+     */
+    public <E extends Enum<E> & EntityType> void mapTypes(EntityType[] oldTypes, Class<E> newTypeClass) {
+        if (typeMappings == null) {
+            typeMappings = new Int2IntOpenHashMap(oldTypes.length, 1F);
+            typeMappings.defaultReturnValue(-1);
+        }
+        for (EntityType oldType : oldTypes) {
+            try {
+                E newType = Enum.valueOf(newTypeClass, oldType.name());
+                typeMappings.put(oldType.getId(), newType.getId());
+            } catch (IllegalArgumentException notFound) {
+                if (!typeMappings.containsKey(oldType.getId())) {
+                    Via.getPlatform().getLogger().warning("Could not find new entity type for " + oldType + "! " +
+                            "Old type: " + oldType.getClass().getEnclosingClass().getSimpleName() + ", new type: " + newTypeClass.getEnclosingClass().getSimpleName());
+                }
+            }
+        }
+    }
+
+    /**
+     * Registers a metadata handler to rewrite, item, block, and particle ids stored in metadata.
+     *
+     * @param itemType     item meta type if needed
+     * @param blockType    block meta type if needed
+     * @param particleType particle meta type if needed
+     * @param itemRewriter itemrewriter if needed
+     */
+    public void registerDumMetaTypeHandler(@Nullable MetaType itemType, @Nullable MetaType blockType, @Nullable MetaType particleType, ItemRewriter.@Nullable RewriteFunction itemRewriter) {
+        filter().handler((event, meta) -> {
+            if (itemType != null && meta.metaType() == itemType) {
+                itemRewriter.rewrite(meta.value());
+            } else if (blockType != null && meta.metaType() == blockType) {
+                int data = meta.value();
+                meta.setValue(protocol.getMappingData().getNewBlockStateId(data));
+            } else if (particleType != null && meta.metaType() == particleType) {
+                rewriteParticle(meta.value());
+            }
+        });
+    }
+
+    public void registerTracker(ClientboundPacketType packetType) {
+        protocol.registerClientbound(packetType, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                map(Type.VAR_INT); // 0 - Entity ID
+                map(Type.UUID); // 1 - Entity UUID
+                map(Type.VAR_INT); // 2 - Entity Type
+                handler(trackerHandler());
+            }
+        });
+    }
+
+    public void registerTrackerWithData(ClientboundPacketType packetType, EntityType fallingBlockType) {
+        protocol.registerClientbound(packetType, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                map(Type.VAR_INT); // 0 - Entity id
+                map(Type.UUID); // 1 - Entity UUID
+                map(Type.VAR_INT); // 2 - Entity Type
+                map(Type.DOUBLE); // 3 - X
+                map(Type.DOUBLE); // 4 - Y
+                map(Type.DOUBLE); // 5 - Z
+                map(Type.BYTE); // 6 - Pitch
+                map(Type.BYTE); // 7 - Yaw
+                map(Type.INT); // 8 - Data
+                handler(trackerHandler());
+                handler(wrapper -> {
+                    int entityId = wrapper.get(Type.VAR_INT, 0);
+                    EntityType entityType = tracker(wrapper.user()).entityType(entityId);
+                    if (entityType == fallingBlockType) {
+                        wrapper.set(Type.INT, 0, protocol.getMappingData().getNewBlockStateId(wrapper.get(Type.INT, 0)));
+                    }
+                });
+            }
+        });
+    }
+
+    /**
+     * Registers an entity tracker for the extra spawn packets like player, painting, or xp orb spawns.
+     *
+     * @param packetType packet type
+     * @param entityType entity type
+     * @param intType    int type of the entity id
+     */
+    public void registerTracker(ClientboundPacketType packetType, EntityType entityType, Type<?> intType) {
+        protocol.registerClientbound(packetType, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    int entityId = (int) wrapper.passthrough(intType);
+                    tracker(wrapper.user()).addEntity(entityId, entityType);
+                });
+            }
+        });
+    }
+
+    /**
+     * Registers an entity tracker for the extra spawn packets.
+     *
+     * @param packetType packet type
+     * @param entityType entity type
+     */
+    public void registerTracker(ClientboundPacketType packetType, EntityType entityType) {
+        registerTracker(packetType, entityType, Type.VAR_INT);
+    }
+
+    /**
+     * Sub 1.17 method for entity remove packets.
+     *
+     * @param packetType remove entities packet type
+     */
+    public void registerRemoveEntities(ClientboundPacketType packetType) {
+        protocol.registerClientbound(packetType, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    int[] entityIds = wrapper.passthrough(Type.VAR_INT_ARRAY_PRIMITIVE);
+                    EntityTracker entityTracker = tracker(wrapper.user());
+                    for (int entity : entityIds) {
+                        entityTracker.removeEntity(entity);
+                    }
+                });
+            }
+        });
+    }
+
+    /**
+     * 1.17+ method for entity remove packets.
+     *
+     * @param packetType remove entities packet type
+     */
+    public void registerRemoveEntity(ClientboundPacketType packetType) {
+        protocol.registerClientbound(packetType, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    int entityId = wrapper.passthrough(Type.VAR_INT);
+                    tracker(wrapper.user()).removeEntity(entityId);
+                });
+            }
+        });
+    }
+
+    public void registerMetadataRewriter(ClientboundPacketType packetType, @Nullable Type<List<Metadata>> oldMetaType, Type<List<Metadata>> newMetaType) {
+        protocol.registerClientbound(packetType, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                map(Type.VAR_INT); // 0 - Entity ID
+                if (oldMetaType != null) {
+                    map(oldMetaType, newMetaType);
+                } else {
+                    map(newMetaType);
+                }
+                handler(wrapper -> {
+                    int entityId = wrapper.get(Type.VAR_INT, 0);
+                    List<Metadata> metadata = wrapper.get(newMetaType, 0);
+                    handleMetadata(entityId, metadata, wrapper.user());
+                });
+            }
+        });
+    }
+
+    public void registerMetadataRewriter(ClientboundPacketType packetType, Type<List<Metadata>> metaType) {
+        registerMetadataRewriter(packetType, null, metaType);
+    }
+
+    public PacketHandler trackerHandler() {
+        return trackerAndRewriterHandler(null);
+    }
+
+    protected PacketHandler worldDataTrackerHandler(int nbtIndex) {
+        return wrapper -> {
+            EntityTracker tracker = tracker(wrapper.user());
+
+            CompoundTag registryData = wrapper.get(Type.NBT, nbtIndex);
+            Tag height = registryData.get("height");
+            if (height instanceof IntTag) {
+                int blockHeight = ((IntTag) height).asInt();
+                tracker.setCurrentWorldSectionHeight(blockHeight >> 4);
+            } else {
+                Via.getPlatform().getLogger().warning("Height missing in dimension data: " + registryData);
+            }
+
+            Tag minY = registryData.get("min_y");
+            if (minY instanceof IntTag) {
+                tracker.setCurrentMinY(((IntTag) minY).asInt());
+            } else {
+                Via.getPlatform().getLogger().warning("Min Y missing in dimension data: " + registryData);
+            }
+        };
+    }
+
+    // ---------------------------------------------------------------------------
+    // Sub 1.14.1 methods
+
+    /**
+     * Returns a packethandler to track and rewrite an entity.
+     *
+     * @param metaType type of the metadata list
+     * @return handler for tracking and rewriting entities
+     */
+    public PacketHandler trackerAndRewriterHandler(@Nullable Type<List<Metadata>> metaType) {
+        return wrapper -> {
+            int entityId = wrapper.get(Type.VAR_INT, 0);
+            int type = wrapper.get(Type.VAR_INT, 1);
+
+            int newType = newEntityId(type);
+            if (newType != type) {
+                wrapper.set(Type.VAR_INT, 1, newType);
+            }
+
+            EntityType entType = typeFromId(trackMappedType ? newType : type);
+            // Register Type ID
+            tracker(wrapper.user()).addEntity(entityId, entType);
+
+            if (metaType != null) {
+                handleMetadata(entityId, wrapper.get(metaType, 0), wrapper.user());
+            }
+        };
+    }
+
+    public PacketHandler trackerAndRewriterHandler(@Nullable Type<List<Metadata>> metaType, EntityType entityType) {
+        return wrapper -> {
+            int entityId = wrapper.get(Type.VAR_INT, 0);
+            // Register Type ID
+            tracker(wrapper.user()).addEntity(entityId, entityType);
+
+            if (metaType != null) {
+                handleMetadata(entityId, wrapper.get(metaType, 0), wrapper.user());
+            }
+        };
+    }
+
+    /**
+     * Returns a packethandler to track an object entity.
+     *
+     * @return handler for tracking and rewriting entities
+     */
+    public PacketHandler objectTrackerHandler() {
+        return wrapper -> {
+            int entityId = wrapper.get(Type.VAR_INT, 0);
+            byte type = wrapper.get(Type.BYTE, 0);
+
+            EntityType entType = objectTypeFromId(type);
+            // Register Type ID
+            tracker(wrapper.user()).addEntity(entityId, entType);
+        };
+    }
+
+    // ---------------------------------------------------------------------------
+
+    @Deprecated
+    protected @Nullable Metadata metaByIndex(int index, List<Metadata> metadataList) {
+        for (Metadata metadata : metadataList) {
+            if (metadata.id() == index) {
+                return metadata;
+            }
+        }
+        return null;
+    }
+
+    protected void rewriteParticle(Particle particle) {
+        ParticleMappings mappings = protocol.getMappingData().getParticleMappings();
+        int id = particle.getId();
+        if (id == mappings.getBlockId() || id == mappings.getFallingDustId()) {
+            Particle.ParticleData data = particle.getArguments().get(0);
+            data.setValue(protocol.getMappingData().getNewBlockStateId(data.get()));
+        } else if (id == mappings.getItemId()) {
+            Particle.ParticleData data = particle.getArguments().get(0);
+            data.setValue(protocol.getMappingData().getNewItemId(data.get()));
+        }
+
+        particle.setId(protocol.getMappingData().getNewParticleId(id));
+    }
+
+    /**
+     * Returns the entity tracker for the current protocol.
+     *
+     * @param connection user connection
+     * @param <T>        entity tracker type
+     * @return entity tracker
+     */
+    public <T extends EntityTracker> T tracker(UserConnection connection) {
+        return connection.getEntityTracker(protocol.getClass());
+    }
+
+    private void logException(Exception e, EntityType type, List<Metadata> metadataList, Metadata metadata) {
+        if (!Via.getConfig().isSuppressMetadataErrors() || Via.getManager().isDebug()) {
+            Logger logger = Via.getPlatform().getLogger();
+            logger.warning("An error occurred with entity metadata handler");
+            logger.warning("This is most likely down to one of your plugins sending bad datawatchers. Please test if this occurs without any plugins except ViaVersion before reporting it on GitHub");
+            logger.warning("Also make sure that all your plugins are compatible with your server version.");
+            logger.warning("Entity type: " + type);
+            logger.warning("Indexed meta: " + metadata);
+            logger.warning(metadataList.stream().sorted(Comparator.comparingInt(Metadata::id))
+                    .map(Metadata::toString).collect(Collectors.joining("\n", "Metadata: ", "")));
+            e.printStackTrace();
+        }
+    }
+}

common/src/main/java/com/viaversion/viaversion/rewriter/MetadataRewriter.java

@@ -1,330 +0,0 @@
-/*
- * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
- * Copyright (C) 2016-2021 ViaVersion and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package com.viaversion.viaversion.rewriter;
-
-import com.viaversion.viaversion.api.Via;
-import com.viaversion.viaversion.api.connection.UserConnection;
-import com.viaversion.viaversion.api.data.ParticleMappings;
-import com.viaversion.viaversion.api.minecraft.entities.EntityType;
-import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
-import com.viaversion.viaversion.api.protocol.Protocol;
-import com.viaversion.viaversion.api.protocol.packet.ClientboundPacketType;
-import com.viaversion.viaversion.api.protocol.remapper.PacketHandler;
-import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
-import com.viaversion.viaversion.api.type.Type;
-import com.viaversion.viaversion.api.type.types.Particle;
-import com.viaversion.viaversion.data.EntityTracker;
-import it.unimi.dsi.fastutil.ints.Int2IntMap;
-import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
-import org.checkerframework.checker.nullness.qual.Nullable;
-
-import java.util.List;
-import java.util.logging.Logger;
-
-public abstract class MetadataRewriter {
-    private static final Metadata[] EMPTY_ARRAY = new Metadata[0];
-    private final Class<? extends EntityTracker> entityTrackerClass;
-    protected final Protocol protocol;
-    private Int2IntMap typeMapping;
-
-    protected MetadataRewriter(Protocol protocol, Class<? extends EntityTracker> entityTrackerClass) {
-        this.protocol = protocol;
-        this.entityTrackerClass = entityTrackerClass;
-        protocol.put(this);
-    }
-
-    public final void handleMetadata(int entityId, List<Metadata> metadatas, UserConnection connection) {
-        EntityType type = connection.get(entityTrackerClass).getEntity(entityId);
-        for (Metadata metadata : metadatas.toArray(EMPTY_ARRAY)) {
-            try {
-                handleMetadata(entityId, type, metadata, metadatas, connection);
-            } catch (Exception e) {
-                metadatas.remove(metadata);
-                if (!Via.getConfig().isSuppressMetadataErrors() || Via.getManager().isDebug()) {
-                    Logger logger = Via.getPlatform().getLogger();
-
-                    logger.warning("An error occurred with entity metadata handler");
-                    logger.warning("This is most likely down to one of your plugins sending bad datawatchers. Please test if this occurs without any plugins except ViaVersion before reporting it on GitHub");
-                    logger.warning("Also make sure that all your plugins are compatible with your server version.");
-                    logger.warning("Entity type: " + type);
-                    logger.warning("Metadata: " + metadata);
-                    e.printStackTrace();
-                }
-            }
-        }
-    }
-
-    protected void rewriteParticle(Particle particle) {
-        ParticleMappings mappings = protocol.getMappingData().getParticleMappings();
-        int id = particle.getId();
-        if (id == mappings.getBlockId() || id == mappings.getFallingDustId()) {
-            Particle.ParticleData data = particle.getArguments().get(0);
-            data.setValue(protocol.getMappingData().getNewBlockStateId(data.get()));
-        } else if (id == mappings.getItemId()) {
-            Particle.ParticleData data = particle.getArguments().get(0);
-            data.setValue(protocol.getMappingData().getNewItemId(data.get()));
-        }
-
-        particle.setId(protocol.getMappingData().getNewParticleId(id));
-    }
-
-    //TODO add respawn/join once they stop changing too much
-
-    public void registerTracker(ClientboundPacketType packetType) {
-        protocol.registerClientbound(packetType, new PacketRemapper() {
-            @Override
-            public void registerMap() {
-                map(Type.VAR_INT); // 0 - Entity ID
-                map(Type.UUID); // 1 - Entity UUID
-                map(Type.VAR_INT); // 2 - Entity Type
-                handler(getTracker());
-            }
-        });
-    }
-
-    public void registerSpawnTrackerWithData(ClientboundPacketType packetType, EntityType fallingBlockType) {
-        protocol.registerClientbound(packetType, new PacketRemapper() {
-            @Override
-            public void registerMap() {
-                map(Type.VAR_INT); // 0 - Entity id
-                map(Type.UUID); // 1 - Entity UUID
-                map(Type.VAR_INT); // 2 - Entity Type
-                map(Type.DOUBLE); // 3 - X
-                map(Type.DOUBLE); // 4 - Y
-                map(Type.DOUBLE); // 5 - Z
-                map(Type.BYTE); // 6 - Pitch
-                map(Type.BYTE); // 7 - Yaw
-                map(Type.INT); // 8 - Data
-                handler(getTracker());
-                handler(wrapper -> {
-                    int entityId = wrapper.get(Type.VAR_INT, 0);
-                    EntityType entityType = wrapper.user().get(entityTrackerClass).getEntity(entityId);
-                    if (entityType == fallingBlockType) {
-                        wrapper.set(Type.INT, 0, protocol.getMappingData().getNewBlockStateId(wrapper.get(Type.INT, 0)));
-                    }
-                });
-            }
-        });
-    }
-
-    public void registerTracker(ClientboundPacketType packetType, EntityType entityType) {
-        protocol.registerClientbound(packetType, new PacketRemapper() {
-            @Override
-            public void registerMap() {
-                map(Type.VAR_INT); // 0 - Entity ID
-                handler(wrapper -> {
-                    int entityId = wrapper.get(Type.VAR_INT, 0);
-                    wrapper.user().get(entityTrackerClass).addEntity(entityId, entityType);
-                });
-            }
-        });
-    }
-
-    /**
-     * Sub 1.17 method for entity remove packets.
-     *
-     * @param packetType remove entities packet type
-     */
-    public void registerEntityDestroy(ClientboundPacketType packetType) {
-        protocol.registerClientbound(packetType, new PacketRemapper() {
-            @Override
-            public void registerMap() {
-                map(Type.VAR_INT_ARRAY_PRIMITIVE); // 0 - Entity ids
-                handler(wrapper -> {
-                    EntityTracker entityTracker = wrapper.user().get(entityTrackerClass);
-                    for (int entity : wrapper.get(Type.VAR_INT_ARRAY_PRIMITIVE, 0)) {
-                        entityTracker.removeEntity(entity);
-                    }
-                });
-            }
-        });
-    }
-
-    /**
-     * 1.17+ method for entity remove packets.
-     *
-     * @param packetType remove entities packet type
-     */
-    public void registerRemoveEntity(ClientboundPacketType packetType) {
-        protocol.registerClientbound(packetType, new PacketRemapper() {
-            @Override
-            public void registerMap() {
-                map(Type.VAR_INT); // 0 - Entity ids
-                handler(wrapper -> {
-                    int entity = wrapper.get(Type.VAR_INT, 0);
-                    wrapper.user().get(entityTrackerClass).removeEntity(entity);
-                });
-            }
-        });
-    }
-
-    public void registerMetadataRewriter(ClientboundPacketType packetType, @Nullable Type<List<Metadata>> oldMetaType, Type<List<Metadata>> newMetaType) {
-        protocol.registerClientbound(packetType, new PacketRemapper() {
-            @Override
-            public void registerMap() {
-                map(Type.VAR_INT); // 0 - Entity ID
-                if (oldMetaType != null) {
-                    map(oldMetaType, newMetaType);
-                } else {
-                    map(newMetaType);
-                }
-                handler(wrapper -> {
-                    int entityId = wrapper.get(Type.VAR_INT, 0);
-                    List<Metadata> metadata = wrapper.get(newMetaType, 0);
-                    handleMetadata(entityId, metadata, wrapper.user());
-                });
-            }
-        });
-    }
-
-    public void registerMetadataRewriter(ClientboundPacketType packetType, Type<List<Metadata>> metaType) {
-        registerMetadataRewriter(packetType, null, metaType);
-    }
-
-    public <T extends Enum<T> & EntityType> void mapTypes(EntityType[] oldTypes, Class<T> newTypeClass) {
-        if (typeMapping == null) {
-            typeMapping = new Int2IntOpenHashMap(oldTypes.length, 1F);
-            typeMapping.defaultReturnValue(-1);
-        }
-        for (EntityType oldType : oldTypes) {
-            try {
-                T newType = Enum.valueOf(newTypeClass, oldType.name());
-                typeMapping.put(oldType.getId(), newType.getId());
-            } catch (IllegalArgumentException notFound) {
-                if (!typeMapping.containsKey(oldType.getId())) {
-                    Via.getPlatform().getLogger().warning("Could not find new entity type for " + oldType + "! " +
-                            "Old type: " + oldType.getClass().getEnclosingClass().getSimpleName() + ", new type: " + newTypeClass.getEnclosingClass().getSimpleName());
-                }
-            }
-        }
-    }
-
-    public void mapType(EntityType oldType, EntityType newType) {
-        if (typeMapping == null) {
-            typeMapping = new Int2IntOpenHashMap();
-            typeMapping.defaultReturnValue(-1);
-        }
-        typeMapping.put(oldType.getId(), newType.getId());
-    }
-
-    public PacketHandler getTracker() {
-        return getTrackerAndRewriter(null);
-    }
-
-    // ---------------------------------------------------------------------------
-    // Sub 1.14.1 methods
-
-    /**
-     * Returns a packethandler to track and rewrite an entity.
-     *
-     * @param metaType type of the metadata list
-     * @return handler for tracking and rewriting entities
-     */
-    public PacketHandler getTrackerAndRewriter(@Nullable Type<List<Metadata>> metaType) {
-        return wrapper -> {
-            int entityId = wrapper.get(Type.VAR_INT, 0);
-            int type = wrapper.get(Type.VAR_INT, 1);
-
-            int newType = getNewEntityId(type);
-            if (newType != type) {
-                wrapper.set(Type.VAR_INT, 1, newType);
-            }
-
-            EntityType entType = getTypeFromId(newType);
-            // Register Type ID
-            wrapper.user().get(entityTrackerClass).addEntity(entityId, entType);
-
-            if (metaType != null) {
-                handleMetadata(entityId, wrapper.get(metaType, 0), wrapper.user());
-            }
-        };
-    }
-
-    public PacketHandler getTrackerAndRewriter(@Nullable Type<List<Metadata>> metaType, EntityType entityType) {
-        return wrapper -> {
-            int entityId = wrapper.get(Type.VAR_INT, 0);
-            // Register Type ID
-            wrapper.user().get(entityTrackerClass).addEntity(entityId, entityType);
-
-            if (metaType != null) {
-                handleMetadata(entityId, wrapper.get(metaType, 0), wrapper.user());
-            }
-        };
-    }
-
-    /**
-     * Returns a packethandler to track an object entity.
-     *
-     * @return handler for tracking and rewriting entities
-     */
-    public PacketHandler getObjectTracker() {
-        return wrapper -> {
-            int entityId = wrapper.get(Type.VAR_INT, 0);
-            byte type = wrapper.get(Type.BYTE, 0);
-
-            EntityType entType = getObjectTypeFromId(type);
-            // Register Type ID
-            wrapper.user().get(entityTrackerClass).addEntity(entityId, entType);
-        };
-    }
-
-    // ---------------------------------------------------------------------------
-
-    protected abstract EntityType getTypeFromId(int type);
-
-    /**
-     * Returns the entity type from the given id.
-     * From 1.14 and onwards, this is the same exact value as {@link #getTypeFromId(int)}.
-     *
-     * @param type entity type id
-     * @return EntityType from id
-     */
-    protected EntityType getObjectTypeFromId(int type) {
-        return getTypeFromId(type);
-    }
-
-    /**
-     * Returns the mapped entitiy (or the same if it has not changed).
-     *
-     * @param oldId old entity id
-     * @return mapped entity id
-     */
-    public int getNewEntityId(int oldId) {
-        return typeMapping != null ? typeMapping.getOrDefault(oldId, oldId) : oldId;
-    }
-
-    /**
-     * To be overridden to handle metadata.
-     *
-     * @param entityId   entity id
-     * @param type       entity type, or null if not tracked
-     * @param metadata   current metadata
-     * @param metadatas  full, mutable list of metadata
-     * @param connection user connection
-     */
-    protected abstract void handleMetadata(int entityId, @Nullable EntityType type, Metadata metadata, List<Metadata> metadatas, UserConnection connection) throws Exception;
-
-    protected @Nullable Metadata getMetaByIndex(int index, List<Metadata> metadataList) {
-        for (Metadata metadata : metadataList) {
-            if (metadata.getId() == index) {
-                return metadata;
-            }
-        }
-        return null;
-    }
-}

common/src/main/java/com/viaversion/viaversion/rewriter/Rewriter.java

@@ -15,15 +15,21 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-package com.viaversion.viaversion.protocols.protocol1_15to1_14_4.storage;
+package com.viaversion.viaversion.rewriter;
 
-import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.protocol.Protocol;
-import com.viaversion.viaversion.api.minecraft.entities.Entity1_15Types;
-import com.viaversion.viaversion.data.EntityTracker;
 
-public class EntityTracker1_15 extends EntityTracker {
+public interface Rewriter<T extends Protocol> {
 
-    public EntityTracker1_15(UserConnection user) {
+    /**
-        super(user, Entity1_15Types.PLAYER);
+     * Registers any packet handlers or rewrites needed.
-    }
+     */
+    void register();
+
+    /**
+     * Returns the {@link Protocol} instance of this rewriter.
+     *
+     * @return protocol of the rewriter
+     */
+    T protocol();
 }

common/src/main/java/com/viaversion/viaversion/rewriter/RewriterBase.java

@@ -15,15 +15,37 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-package com.viaversion.viaversion.protocols.protocol1_14_1to1_14.storage;
+package com.viaversion.viaversion.rewriter;
 
-import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.protocol.Protocol;
-import com.viaversion.viaversion.api.minecraft.entities.Entity1_14Types;
-import com.viaversion.viaversion.data.EntityTracker;
 
-public class EntityTracker1_14_1 extends EntityTracker {
+public abstract class RewriterBase<T extends Protocol> implements Rewriter<T> {
+    protected final T protocol;
 
-    public EntityTracker1_14_1(UserConnection user) {
+    protected RewriterBase(T protocol) {
-        super(user, Entity1_14Types.PLAYER);
+        this.protocol = protocol;
+    }
+
+    @Override
+    public void register() {
+        registerPackets();
+        registerRewrites();
+    }
+
+    /**
+     * To be overriden. Called when initializing the EntityRewriter.
+     */
+    protected void registerPackets() {
+    }
+
+    /**
+     * To be overriden. Called when initializing the EntityRewriter.
+     */
+    protected void registerRewrites() {
+    }
+
+    @Override
+    public T protocol() {
+        return protocol;
     }
 }

common/src/main/java/com/viaversion/viaversion/rewriter/meta/MetaFilter.java

@@ -0,0 +1,244 @@
+/*
+ * This file is part of ViaBackwards - https://github.com/ViaVersion/ViaBackwards
+ * Copyright (C) 2016-2021 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.viaversion.viaversion.rewriter.meta;
+
+import com.google.common.base.Preconditions;
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
+import com.viaversion.viaversion.rewriter.EntityRewriter;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import java.util.Objects;
+
+public class MetaFilter {
+    private final MetaHandler handler;
+    private final EntityType type;
+    private final int index;
+    private final boolean filterFamily;
+
+    public MetaFilter(@Nullable EntityType type, boolean filterFamily, int index, MetaHandler handler) {
+        Preconditions.checkNotNull(handler, "MetaHandler cannot be null");
+        this.type = type;
+        this.filterFamily = filterFamily;
+        this.index = index;
+        this.handler = handler;
+    }
+
+    /**
+     * Returns the metadata index to filter, or -1.
+     *
+     * @return metadata index, or -1 if unset
+     */
+    public int index() {
+        return index;
+    }
+
+    /**
+     * Returns the filtered entity type if present.
+     *
+     * @return filtered entity type if present
+     */
+    public @Nullable EntityType type() {
+        return type;
+    }
+
+    /**
+     * Returns the metadata handler.
+     *
+     * @return metadata handler
+     */
+    public MetaHandler handler() {
+        return handler;
+    }
+
+    /**
+     * Returns whether entity parent types should be checked against as well.
+     *
+     * @return whether entity parent types should be checked against
+     */
+    public boolean filterFamily() {
+        return filterFamily;
+    }
+
+    /**
+     * Returns whether if the metadata should be handled by this filter.
+     *
+     * @param type     entity type
+     * @param metadata metadata
+     * @return whether the meta should be filtered
+     */
+    public boolean isFiltered(EntityType type, Metadata metadata) {
+        // First check if the filter has no type or the type is equal or part of the filtered parent types
+        // Applicable if no specific index is filtered or the indexes are equal
+        return (this.type == null || (filterFamily ? type.isOrHasParent(this.type) : this.type == type)) && (index == -1 || metadata.id() == index);
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        MetaFilter that = (MetaFilter) o;
+        if (index != that.index) return false;
+        if (filterFamily != that.filterFamily) return false;
+        if (!handler.equals(that.handler)) return false;
+        return Objects.equals(type, that.type);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = handler.hashCode();
+        result = 31 * result + (type != null ? type.hashCode() : 0);
+        result = 31 * result + index;
+        result = 31 * result + (filterFamily ? 1 : 0);
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "MetaFilter{" +
+                "type=" + type +
+                ", filterFamily=" + filterFamily +
+                ", index=" + index +
+                ", handler=" + handler +
+                '}';
+    }
+
+    public static final class Builder {
+        private final EntityRewriter rewriter;
+        private EntityType type;
+        private int index = -1;
+        private boolean filterFamily;
+        private MetaHandler handler;
+
+        public Builder(EntityRewriter rewriter) {
+            this.rewriter = rewriter;
+        }
+
+        public Builder type(EntityType type) {
+            Preconditions.checkArgument(this.type == null);
+            this.type = type;
+            return this;
+        }
+
+        public Builder index(int index) {
+            Preconditions.checkArgument(this.index == -1);
+            this.index = index;
+            return this;
+        }
+
+        public Builder filterFamily(EntityType type) {
+            Preconditions.checkArgument(this.type == null);
+            this.type = type;
+            this.filterFamily = true;
+            return this;
+        }
+
+        public Builder handlerNoRegister(MetaHandler handler) {
+            Preconditions.checkArgument(this.handler == null);
+            this.handler = handler;
+            return this;
+        }
+
+        /**
+         * Sets the metadata handler and registers the metadata filter.
+         * Should always be called last.
+         *
+         * @param handler metadata handler
+         */
+        public void handler(MetaHandler handler) {
+            Preconditions.checkArgument(this.handler == null);
+            this.handler = handler;
+            register();
+        }
+
+        /**
+         * Sets a handler to remove metadata at the given index without affecting any other indexes and registers the filter.
+         * Should always be called last.
+         *
+         * @param index index to cancel
+         */
+        public void cancel(int index) {
+            this.index = index;
+            handler((event, meta) -> event.cancel());
+        }
+
+        /**
+         * Sets a handler to change the index. Does not do any other transformation or shifting and registers the filter.
+         * Should always be called last.
+         *
+         * @param newIndex new index
+         * @throws IllegalArgumentException if no index has been set yet
+         */
+        public void toIndex(int newIndex) {
+            Preconditions.checkArgument(this.index != -1);
+            handler((event, meta) -> event.setIndex(newIndex));
+        }
+
+        /**
+         * Sets a handler incrementing every index above the given one and registers the filter.
+         * Should always be called last.
+         *
+         * @param index index to pad
+         * @throws IllegalArgumentException if the index has already been set
+         */
+        public void addIndex(int index) {
+            Preconditions.checkArgument(this.index == -1);
+            handler((event, meta) -> {
+                if (event.index() >= index) {
+                    event.setIndex(event.index() + 1);
+                }
+            });
+        }
+
+        /**
+         * Sets a handler to remove metadata at the given index, decrementing every index above it and registers the filter.
+         * Should always be called last.
+         *
+         * @param index index to remove
+         * @throws IllegalArgumentException if the index has already been set
+         */
+        public void removeIndex(int index) {
+            Preconditions.checkArgument(this.index == -1);
+            handler((event, meta) -> {
+                int metaIndex = event.index();
+                if (metaIndex == index) {
+                    event.cancel();
+                } else if (metaIndex > index) {
+                    event.setIndex(metaIndex - 1);
+                }
+            });
+        }
+
+        /**
+         * Creates and registers the created MetaFilter in the linked {@link EntityRewriter} instance.
+         */
+        public void register() {
+            rewriter.registerFilter(build());
+        }
+
+        /**
+         * Returns a new metadata filter without registering it.
+         *
+         * @return created meta filter
+         */
+        public MetaFilter build() {
+            return new MetaFilter(type, filterFamily, index, handler);
+        }
+    }
+}

common/src/main/java/com/viaversion/viaversion/rewriter/meta/MetaHandler.java

@@ -1,5 +1,5 @@
 /*
- * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * This file is part of ViaBackwards - https://github.com/ViaVersion/ViaBackwards
  * Copyright (C) 2016-2021 ViaVersion and contributors
  *
  * This program is free software: you can redistribute it and/or modify
@@ -15,15 +15,19 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-package com.viaversion.viaversion.protocols.protocol1_16to1_15_2.storage;
 
-import com.viaversion.viaversion.api.connection.UserConnection;
+package com.viaversion.viaversion.rewriter.meta;
-import com.viaversion.viaversion.api.minecraft.entities.Entity1_16Types;
-import com.viaversion.viaversion.data.EntityTracker;
 
-public class EntityTracker1_16 extends EntityTracker {
+import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
 
-    public EntityTracker1_16(UserConnection user) {
+@FunctionalInterface
-        super(user, Entity1_16Types.PLAYER);
+public interface MetaHandler {
-    }
+
+    /**
+     * Handles a metadata entry of an entity.
+     *
+     * @param event metadata event
+     * @param meta  metadata, convenience field for {@link MetaHandlerEvent#meta()}
+     */
+    void handle(MetaHandlerEvent event, Metadata meta);
 }

common/src/main/java/com/viaversion/viaversion/rewriter/meta/MetaHandlerEvent.java

@@ -0,0 +1,121 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2021 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viaversion.rewriter.meta;
+
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import java.util.List;
+
+public interface MetaHandlerEvent {
+
+    /**
+     * Returns the user connection the metadata is sent to.
+     *
+     * @return user connection
+     */
+    UserConnection user();
+
+    /**
+     * Returns the entity id of the entity.
+     *
+     * @return entity id
+     */
+    int entityId();
+
+    /**
+     * Returns the entity type of the entity the metadata belongs to.
+     *
+     * @return entity type of the entity
+     */
+    EntityType entityType();
+
+    /**
+     * Returns the metadata index.
+     *
+     * @return return meta index
+     */
+    int index();
+
+    /**
+     * Sets the metadata index.
+     *
+     * @param index new metadata index
+     */
+    void setIndex(int index);
+
+    /**
+     * Returns the metadata by the given index if present.
+     *
+     * @param index metadata index
+     * @return metadata by index if present
+     */
+    @Nullable Metadata getMetaByIndex(int index);
+
+    /**
+     * Returns the metadata.
+     * Do NOT call {@link Metadata#setId(int)} and instead use {@link MetaHandlerEvent#setIndex(int)}.
+     *
+     * @return return metadata
+     */
+    Metadata meta();
+
+    /**
+     * Prevents other handlers from being called with this metadata entry and removes it from the list.
+     */
+    void cancel();
+
+    /**
+     * Returns whether this metadata entry should be removed.
+     *
+     * @return true if cancelled/removed
+     */
+    boolean cancelled();
+
+    /**
+     * Returns an immutable metadata view.
+     *
+     * @return immutable metadata list
+     * @see #cancel()
+     * @see #createExtraMeta(Metadata)
+     */
+    List<Metadata> metadataList();
+
+    /**
+     * Returns additionally created metadata.
+     * May be null; use {@link #createExtraMeta(Metadata)} for adding metadata.
+     *
+     * @return additionally created metadata if present
+     */
+    @Nullable List<Metadata> extraMeta();
+
+    /**
+     * Adds the given metadata to the metadata list.
+     * This metadata will not be passed through handlers of the current loop.
+     *
+     * @param metadata metadata
+     */
+    void createExtraMeta(Metadata metadata);
+
+    /**
+     * Clears the additional metadata.
+     */
+    void clearExtraMeta();
+}

common/src/main/java/com/viaversion/viaversion/rewriter/meta/MetaHandlerEventImpl.java

@@ -0,0 +1,119 @@
+/*
+ * This file is part of ViaBackwards - https://github.com/ViaVersion/ViaBackwards
+ * Copyright (C) 2016-2021 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.viaversion.viaversion.rewriter.meta;
+
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class MetaHandlerEventImpl implements MetaHandlerEvent {
+    private final UserConnection connection;
+    private final EntityType entityType;
+    private final int entityId;
+    private final List<Metadata> metadataList;
+    private final Metadata meta;
+    private List<Metadata> extraData;
+    private int index;
+    private boolean cancel;
+
+    public MetaHandlerEventImpl(UserConnection connection, EntityType entityType, int entityId, int index, Metadata meta, List<Metadata> metadataList) {
+        this.connection = connection;
+        this.entityType = entityType;
+        this.entityId = entityId;
+        this.index = index;
+        this.meta = meta;
+        this.metadataList = metadataList;
+    }
+
+    @Override
+    public @Nullable Metadata getMetaByIndex(int index) {
+        for (Metadata meta : metadataList) {
+            if (index == meta.id()) {
+                return meta;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public UserConnection user() {
+        return connection;
+    }
+
+    @Override
+    public int entityId() {
+        return entityId;
+    }
+
+    @Override
+    public EntityType entityType() {
+        return entityType;
+    }
+
+    @Override
+    public int index() {
+        return index;
+    }
+
+    @Override
+    public void setIndex(int index) {
+        this.index = index;
+        meta.setId(index);
+    }
+
+    @Override
+    public Metadata meta() {
+        return meta;
+    }
+
+    @Override
+    public void cancel() {
+        this.cancel = true;
+    }
+
+    @Override
+    public boolean cancelled() {
+        return cancel;
+    }
+
+    @Override
+    public List<Metadata> metadataList() {
+        return Collections.unmodifiableList(metadataList);
+    }
+
+    @Override
+    public @Nullable List<Metadata> extraMeta() {
+        return extraData;
+    }
+
+    @Override
+    public void createExtraMeta(Metadata metadata) {
+        (extraData != null ? extraData : (extraData = new ArrayList<>())).add(metadata);
+    }
+
+    @Override
+    public void clearExtraMeta() {
+        extraData = null;
+    }
+}

sponge/src/main/java/com/viaversion/viaversion/sponge/listeners/protocol1_9to1_8/BlockListener.java

@@ -18,6 +18,7 @@
 package com.viaversion.viaversion.sponge.listeners.protocol1_9to1_8;
 
 import com.viaversion.viaversion.SpongePlugin;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
 import com.viaversion.viaversion.api.minecraft.Position;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.EntityTracker1_9;
@@ -38,9 +39,8 @@ public class BlockListener extends ViaSpongeListener {
     public void placeBlock(ChangeBlockEvent.Place e, @Root Player player) {
         if (isOnPipe(player.getUniqueId())) {
             Location loc = e.getTransactions().get(0).getFinal().getLocation().get();
-            getUserConnection(player.getUniqueId())
+            EntityTracker1_9 tracker = getUserConnection(player.getUniqueId()).getEntityTracker(Protocol1_9To1_8.class);
-                    .get(EntityTracker1_9.class)
+            tracker.addBlockInteraction(new Position(loc.getBlockX(), (short) loc.getBlockY(), loc.getBlockZ()));
-                    .addBlockInteraction(new Position(loc.getBlockX(), (short) loc.getBlockY(), loc.getBlockZ()));
         }
     }
 }