Merge branch 'master' into gh-pages

ProtocolLib/dependency-reduced-pom.xml

@@ -4,7 +4,7 @@
   <groupId>com.comphenix.protocol</groupId>
   <artifactId>ProtocolLib</artifactId>
   <name>ProtocolLib</name>
-  <version>1.5.1</version>
+  <version>1.6.0</version>
   <description>Provides read/write access to the Minecraft protocol.</description>
   <url>http://dev.bukkit.org/server-mods/protocollib/</url>
   <developers>

ProtocolLib/pom.xml

@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.comphenix.protocol</groupId>
   <artifactId>ProtocolLib</artifactId>
-  <version>1.5.1</version>
+  <version>1.6.0</version>
   <packaging>jar</packaging>
   <description>Provides read/write access to the Minecraft protocol.</description>
   

ProtocolLib/src/main/java/com/comphenix/protocol/CleanupStaticMembers.java

@@ -19,6 +19,9 @@ import com.comphenix.protocol.reflect.compiler.StructureCompiler;
 import com.comphenix.protocol.reflect.instances.CollectionGenerator;
 import com.comphenix.protocol.reflect.instances.DefaultInstances;
 import com.comphenix.protocol.reflect.instances.PrimitiveGenerator;
+import com.comphenix.protocol.wrappers.ChunkPosition;
+import com.comphenix.protocol.wrappers.WrappedDataWatcher;
+import com.comphenix.protocol.wrappers.WrappedWatchableObject;
 
 /**
  * Used to fix ClassLoader leaks that may lead to filling up the permanent generation.
@@ -45,7 +48,8 @@ class CleanupStaticMembers {
 				BukkitUnwrapper.class, DefaultInstances.class, CollectionGenerator.class,
 				PrimitiveGenerator.class, FuzzyReflection.class, MethodUtils.class, 
 				BackgroundCompiler.class, StructureCompiler.class,
-				ObjectCloner.class, Packets.Server.class, Packets.Client.class 
+				ObjectCloner.class, Packets.Server.class, Packets.Client.class, 
+				ChunkPosition.class, WrappedDataWatcher.class, WrappedWatchableObject.class
 		};
 							   			
 		String[] internalClasses = {

ProtocolLib/src/main/java/com/comphenix/protocol/CommandBase.java

@@ -5,6 +5,8 @@ import org.bukkit.command.Command;
 import org.bukkit.command.CommandExecutor;
 import org.bukkit.command.CommandSender;
 
+import com.comphenix.protocol.error.ErrorReporter;
+
 /**
  * Base class for all our commands.
  * 
@@ -17,12 +19,14 @@ abstract class CommandBase implements CommandExecutor {
 	private String permission;
 	private String name;
 	private int minimumArgumentCount;
+	private ErrorReporter reporter;
 	
-	public CommandBase(String permission, String name) {
+	public CommandBase(ErrorReporter reporter, String permission, String name) {
-		this(permission, name, 0);
+		this(reporter, permission, name, 0);
 	}
 	
-	public CommandBase(String permission, String name, int minimumArgumentCount) {
+	public CommandBase(ErrorReporter reporter, String permission, String name, int minimumArgumentCount) {
+		this.reporter = reporter;
 		this.name = name;
 		this.permission = permission;
 		this.minimumArgumentCount = minimumArgumentCount;
@@ -30,11 +34,12 @@ abstract class CommandBase implements CommandExecutor {
 
 	@Override
 	public final boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+		try {
 			// Make sure we're dealing with the correct command
 			if (!command.getName().equalsIgnoreCase(name)) {
 				return false;
 			}
-		if (!sender.hasPermission(permission)) {
+			if (permission != null && !sender.hasPermission(permission)) {
 				sender.sendMessage(ChatColor.RED + "You haven't got permission to run this command.");
 				return true;
 			}
@@ -45,7 +50,42 @@ abstract class CommandBase implements CommandExecutor {
 			} else {
 				return false;
 			}
+			
+		} catch (Exception e) {
+			reporter.reportDetailed(this, "Cannot execute command " + name, e, sender, label, args);
+			return true;
+		}
 	}
 	
+	/**
+	 * Retrieve the permission necessary to execute this command.
+	 * @return The permission, or NULL if not needed.
+	 */
+	public String getPermission() {
+		return permission;
+	}
+	
+	/**
+	 * Retrieve the primary name of this command.
+	 * @return Primary name.
+	 */
+	public String getName() {
+		return name;
+	}
+	
+	/**
+	 * Retrieve the error reporter.
+	 * @return Error reporter.
+	 */
+	protected ErrorReporter getReporter() {
+		return reporter;
+	}
+	
+	/**
+	 * Main implementation of this command.
+	 * @param sender - command sender.
+	 * @param args
+	 * @return
+	 */
 	protected abstract boolean handleCommand(CommandSender sender, String[] args);
 }

ProtocolLib/src/main/java/com/comphenix/protocol/CommandPacket.java

@@ -32,6 +32,7 @@ import com.comphenix.protocol.utility.ChatExtensions;
 import com.google.common.collect.DiscreteDomains;
 import com.google.common.collect.Range;
 import com.google.common.collect.Ranges;
+import com.google.common.collect.Sets;
 
 /**
  * Handles the "packet" debug command.
@@ -76,11 +77,10 @@ class CommandPacket extends CommandBase {
 	private AbstractIntervalTree<Integer, DetailedPacketListener> clientListeners = createTree(ConnectionSide.CLIENT_SIDE);
 	private AbstractIntervalTree<Integer, DetailedPacketListener> serverListeners = createTree(ConnectionSide.SERVER_SIDE);
 	
-	public CommandPacket(Plugin plugin, Logger logger, ErrorReporter reporter, ProtocolManager manager) {
+	public CommandPacket(ErrorReporter reporter, Plugin plugin, Logger logger, ProtocolManager manager) {
-		super(CommandBase.PERMISSION_ADMIN, NAME, 2);
+		super(reporter, CommandBase.PERMISSION_ADMIN, NAME, 1);
 		this.plugin = plugin;
 		this.logger = logger;
-		this.reporter = reporter;
 		this.manager = manager;
 		this.chatter = new ChatExtensions(manager);
 	}
@@ -228,6 +228,12 @@ class CommandPacket extends CommandBase {
 			
 			// Perform commands
 			if (subCommand == SubCommand.ADD) {
+				// The add command is dangerous - don't default on the connection side
+				if (args.length == 1) {
+					sender.sendMessage(ChatColor.RED + "Please specify a connectionn side.");
+					return false;
+				}
+				
 				executeAddCommand(sender, side, detailed, ranges);
 			} else if (subCommand == SubCommand.REMOVE) {
 				executeRemoveCommand(sender, side, detailed, ranges);
@@ -308,18 +314,19 @@ class CommandPacket extends CommandBase {
 	}
 	
 	private Set<Integer> getValidPackets(ConnectionSide side) throws FieldAccessException {
+		HashSet<Integer> supported = Sets.newHashSet();
+		
 		if (side.isForClient())
-			return Packets.Client.getSupported();
+			supported.addAll(Packets.Client.getSupported());
 		else if (side.isForServer())
-			return Packets.Server.getSupported();
+			supported.addAll(Packets.Server.getSupported());
-		else
+		return supported;
-			throw new IllegalArgumentException("Illegal side: " + side);
 	}
 	
 	private Set<Integer> getNamedPackets(ConnectionSide side) {
 		
 		Set<Integer> valids = null;
-		Set<Integer> result = null;
+		Set<Integer> result = Sets.newHashSet();
 		
 		try {
 			valids = getValidPackets(side);
@@ -329,11 +336,9 @@ class CommandPacket extends CommandBase {
 		
 		// Check connection side
 		if (side.isForClient())
-			result = Packets.Client.getRegistry().values();
+			result.addAll(Packets.Client.getRegistry().values());
-		else if (side.isForServer())
+		if (side.isForServer())
-			result = Packets.Server.getRegistry().values();
+			result.addAll(Packets.Server.getRegistry().values());
-		else
-			throw new IllegalArgumentException("Illegal side: " + side);
 		
 		// Remove invalid packets
 		result.retainAll(valids);
@@ -378,10 +383,10 @@ class CommandPacket extends CommandBase {
 			}
 			
 			private void printInformation(PacketEvent event) {
-				String verb = side.isForClient() ? "Received" : "Sent";
+				String format = side.isForClient() ? 
-				String shortDescription = String.format(
+						"Received %s (%s) from %s" : 
-						"%s %s (%s) from %s",
+						"Sent %s (%s) to %s";
-						verb, 
+				String shortDescription = String.format(format,
 						Packets.getDeclaredName(event.getPacketID()),
 						event.getPacketID(),
 						event.getPlayer().getName()
@@ -438,7 +443,10 @@ class CommandPacket extends CommandBase {
 		
 		// The trees will manage the listeners for us
 		if (listener != null) {
-			getListenerTree(side).put(idStart, idStop, listener);
+			if (side.isForClient())
+				clientListeners.put(idStart, idStop, listener);
+			if (side.isForServer())
+				serverListeners.put(idStart, idStop, listener);
 			return listener;
 		} else {
 			throw new IllegalArgumentException("No packets found in the range " + idStart + " - " + idStop + ".");
@@ -448,17 +456,14 @@ class CommandPacket extends CommandBase {
 	public Set<AbstractIntervalTree<Integer, DetailedPacketListener>.Entry> removePacketListeners(
 			ConnectionSide side, int idStart, int idStop, boolean detailed) {
 		
-		// The interval tree will automatically remove the listeners for us
+		HashSet<AbstractIntervalTree<Integer, DetailedPacketListener>.Entry> result = Sets.newHashSet();
-		return getListenerTree(side).remove(idStart, idStop);
-	}
 		
-	private AbstractIntervalTree<Integer, DetailedPacketListener> getListenerTree(ConnectionSide side) {
+		// The interval tree will automatically remove the listeners for us
 		if (side.isForClient())
-			return clientListeners;
+			result.addAll(clientListeners.remove(idStart, idStop));
-		else if (side.isForServer())
+		if (side.isForServer())
-			return serverListeners;
+			result.addAll(serverListeners.remove(idStart, idStop));
-		else
+		return result;
-			throw new IllegalArgumentException("Not a legal connection side.");
 	}
 
 	private SubCommand parseCommand(String[] args, int index) {

ProtocolLib/src/main/java/com/comphenix/protocol/CommandProtocol.java

@@ -4,6 +4,7 @@ import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
 import org.bukkit.plugin.Plugin;
 
+import com.comphenix.protocol.error.ErrorReporter;
 import com.comphenix.protocol.metrics.Updater;
 import com.comphenix.protocol.metrics.Updater.UpdateResult;
 import com.comphenix.protocol.metrics.Updater.UpdateType;
@@ -23,8 +24,8 @@ class CommandProtocol extends CommandBase {
 	private Updater updater;
 	private ProtocolConfig config;
 
-	public CommandProtocol(Plugin plugin, Updater updater, ProtocolConfig config) {
+	public CommandProtocol(ErrorReporter reporter, Plugin plugin, Updater updater, ProtocolConfig config) {
-		super(CommandBase.PERMISSION_ADMIN, NAME, 1);
+		super(reporter, CommandBase.PERMISSION_ADMIN, NAME, 1);
 		this.plugin = plugin;
 		this.updater = updater;
 		this.config = config;
@@ -51,8 +52,12 @@ class CommandProtocol extends CommandBase {
 		plugin.getServer().getScheduler().scheduleAsyncDelayedTask(plugin, new Runnable() {
 			@Override
 			public void run() {
+				try {
 					UpdateResult result = updater.update(UpdateType.NO_DOWNLOAD, true);
 					sender.sendMessage(ChatColor.BLUE + "[ProtocolLib] " + result.toString());
+				} catch (Exception e) {
+					getReporter().reportDetailed(this, "Cannot check updates for ProtocolLib.", e, sender);
+				}
 			}
 		});
 		
@@ -64,8 +69,12 @@ class CommandProtocol extends CommandBase {
 		plugin.getServer().getScheduler().scheduleAsyncDelayedTask(plugin, new Runnable() {
 			@Override
 			public void run() {
+				try {
 					UpdateResult result = updater.update(UpdateType.DEFAULT, true);
 					sender.sendMessage(ChatColor.BLUE + "[ProtocolLib] " + result.toString());
+				} catch (Exception e) {
+					getReporter().reportDetailed(this, "Cannot update ProtocolLib.", e, sender);
+				}
 			}
 		});
 		

ProtocolLib/src/main/java/com/comphenix/protocol/ProtocolConfig.java

@@ -24,7 +24,7 @@ class ProtocolConfig {
 	private static final String UPDATER_LAST_TIME = "last";
 	
 	// Defaults
-	private static final long DEFAULT_UPDATER_DELAY = 60;
+	private static final long DEFAULT_UPDATER_DELAY = 43200;
 	
 	private Plugin plugin;
 	private Configuration config;
@@ -47,7 +47,7 @@ class ProtocolConfig {
 	 */
 	public void reloadConfig() {
 		this.config = plugin.getConfig();
-		loadSections(true);
+		loadSections(!loadingSections);
 	}
 	
 	/**
@@ -55,9 +55,6 @@ class ProtocolConfig {
 	 * @param copyDefaults - whether or not to copy configuration defaults.
 	 */
 	private void loadSections(boolean copyDefaults) {
-		if (loadingSections)
-			return;
-		
 		if (config != null) {
 			global = config.getConfigurationSection(SECTION_GLOBAL);
 		}
@@ -72,10 +69,8 @@ class ProtocolConfig {
 			if (config != null)
 				config.options().copyDefaults(true);
 			plugin.saveDefaultConfig();
-			config = plugin.getConfig();
+			plugin.reloadConfig();
-		
 			loadingSections = false;	
-			loadSections(false);
 			
 			// Inform the user
 			System.out.println("[ProtocolLib] Created default configuration.");

ProtocolLib/src/main/java/com/comphenix/protocol/ProtocolLibrary.java

@@ -75,6 +75,7 @@ public class ProtocolLibrary extends JavaPlugin {
 	
 	// Updater
 	private Updater updater;
+	private boolean updateDisabled;
 	
 	// Logger
 	private Logger logger;
@@ -108,8 +109,8 @@ public class ProtocolLibrary extends JavaPlugin {
 			reporter.addGlobalParameter("manager", protocolManager);
 			
 			// Initialize command handlers
-			commandProtocol = new CommandProtocol(this, updater, config);
+			commandProtocol = new CommandProtocol(reporter, this, updater, config);
-			commandPacket = new CommandPacket(this, logger, reporter, protocolManager);
+			commandPacket = new CommandPacket(reporter, this, logger, protocolManager);
 			
 			// Send logging information to player listeners too
 			broadcastUsers(PERMISSION_INFO);
@@ -127,6 +128,7 @@ public class ProtocolLibrary extends JavaPlugin {
 	@Override
 	public void reloadConfig() {
 		super.reloadConfig();
+		
 		// Reload configuration
 		if (config != null) {
 			config.reloadConfig();
@@ -223,8 +225,10 @@ public class ProtocolLibrary extends JavaPlugin {
 					manager.sendProcessedPackets(tickCounter++, true);
 					
 					// Check for updates too
+					if (!updateDisabled) {
 						checkUpdates();
 					}
+				}
 			}, ASYNC_PACKET_DELAY, ASYNC_PACKET_DELAY);
 		
 		} catch (Throwable e) {
@@ -238,8 +242,11 @@ public class ProtocolLibrary extends JavaPlugin {
 		// Ignore milliseconds - it's pointless
 		long currentTime = System.currentTimeMillis() / MILLI_PER_SECOND;
 		
+		try {
+			long updateTime = config.getAutoLastTime() + config.getAutoDelay();
+
 			// Should we update?
-		if (currentTime > config.getAutoLastTime() + config.getAutoDelay()) {			
+			if (currentTime > updateTime) {		
 				// Initiate the update as if it came from the console
 				if (config.isAutoDownload())
 					commandProtocol.updateVersion(getServer().getConsoleSender());
@@ -248,6 +255,10 @@ public class ProtocolLibrary extends JavaPlugin {
 				else 
 					commandProtocol.updateFinished();
 			}
+		} catch (Exception e) {
+			reporter.reportDetailed(this, "Cannot perform automatic updates.", e);
+			updateDisabled = true;
+		}
 	}
 	
 	private void checkForIncompatibility(PluginManager manager) {

ProtocolLib/src/main/java/com/comphenix/protocol/ProtocolManager.java

@@ -20,6 +20,7 @@ package com.comphenix.protocol;
 import java.util.List;
 import java.util.Set;
 
+import org.bukkit.World;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
@@ -105,6 +106,15 @@ public interface ProtocolManager extends PacketStream {
 	 */
 	public void updateEntity(Entity entity, List<Player> observers) throws FieldAccessException;
 	
+	/**
+	 * Retrieve the associated entity.
+	 * @param container - the world the entity belongs to.
+	 * @param id - the unique ID of the entity.
+	 * @return The associated entity.
+	 * @throws FieldAccessException Reflection failed.
+	 */
+	public Entity getEntityFromID(World container, int id) throws FieldAccessException;
+	
 	/**
 	 * Retrieves a immutable set containing the ID of the sent server packets that will be observed by listeners.
 	 * @return Every filtered server packet.

ProtocolLib/src/main/java/com/comphenix/protocol/async/PacketSendingQueue.java

@@ -27,7 +27,6 @@ import org.bukkit.entity.Player;
 
 import com.comphenix.protocol.events.PacketEvent;
 import com.comphenix.protocol.injector.PlayerLoggedOutException;
-import com.comphenix.protocol.injector.SortedPacketListenerList;
 import com.comphenix.protocol.reflect.FieldAccessException;
 
 /**

ProtocolLib/src/main/java/com/comphenix/protocol/events/PacketAdapter.java

@@ -104,7 +104,7 @@ public abstract class PacketAdapter implements PacketListener {
 	 * @param packets - the packet IDs the listener is looking for.
 	 */
 	public PacketAdapter(Plugin plugin, ConnectionSide connectionSide, GamePhase gamePhase, Integer... packets) {
-		this(plugin, connectionSide, ListenerPriority.NORMAL, GamePhase.PLAYING, packets);
+		this(plugin, connectionSide, ListenerPriority.NORMAL, gamePhase, packets);
 	}
 	
 	/**

ProtocolLib/src/main/java/com/comphenix/protocol/events/PacketContainer.java

@@ -25,21 +25,22 @@ import java.io.ObjectOutputStream;
 import java.io.Serializable;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.Collection;
+import java.util.List;
 
-import org.bukkit.Bukkit;
-import org.bukkit.Server;
 import org.bukkit.World;
 import org.bukkit.WorldType;
-import org.bukkit.craftbukkit.CraftWorld;
-import org.bukkit.craftbukkit.inventory.CraftItemStack;
 import org.bukkit.entity.Entity;
-import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 
 import com.comphenix.protocol.injector.StructureCache;
 import com.comphenix.protocol.reflect.EquivalentConverter;
 import com.comphenix.protocol.reflect.FuzzyReflection;
 import com.comphenix.protocol.reflect.StructureModifier;
+import com.comphenix.protocol.wrappers.BukkitConverters;
+import com.comphenix.protocol.wrappers.ChunkPosition;
+import com.comphenix.protocol.wrappers.WrappedDataWatcher;
+import com.comphenix.protocol.wrappers.WrappedWatchableObject;
 
 import net.minecraft.server.Packet;
 
@@ -61,24 +62,10 @@ public class PacketContainer implements Serializable {
 	// Current structure modifier
 	protected transient StructureModifier<Object> structureModifier;
 		
-	// Check whether or not certain classes exists
-	private static boolean hasWorldType = false;
-	
-	// The getEntity method
-	private static Method getEntity;
-	
 	// Support for serialization
 	private static Method writeMethod;
 	private static Method readMethod;
 		
-	static {
-		try {
-			Class.forName("net.minecraft.server.WorldType");
-			hasWorldType = true;
-		} catch (ClassNotFoundException e) {
-		}
-	}
-	
 	/**
 	 * Creates a packet container for a new packet.
 	 * @param id - ID of the packet to create.
@@ -136,6 +123,77 @@ public class PacketContainer implements Serializable {
 		return structureModifier.withType(primitiveType);
 	}
 	
+	/**
+	 * Retrieves a read/write structure for every byte field.
+	 * @return A modifier for every byte field.
+	 */
+	public StructureModifier<Byte> getBytes() {
+		return structureModifier.withType(byte.class);
+	}
+	
+	/**
+	 * Retrieves a read/write structure for every short field.
+	 * @return A modifier for every short field.
+	 */
+	public StructureModifier<Short> getShorts() {
+		return structureModifier.withType(short.class);
+	}
+	
+	/**
+	 * Retrieves a read/write structure for every integer field.
+	 * @return A modifier for every integer field.
+	 */
+	public StructureModifier<Integer> getIntegers() {
+		return structureModifier.withType(int.class);
+	}
+	/**
+	 * Retrieves a read/write structure for every long field.
+	 * @return A modifier for every long field.
+	 */
+	public StructureModifier<Long> getLongs() {
+		return structureModifier.withType(long.class);
+	}
+	
+	/**
+	 * Retrieves a read/write structure for every float field.
+	 * @return A modifier for every float field.
+	 */
+	public StructureModifier<Float> getFloat() {
+		return structureModifier.withType(float.class);
+	}
+	
+	/**
+	 * Retrieves a read/write structure for every double field.
+	 * @return A modifier for every double field.
+	 */
+	public StructureModifier<Double> getDoubles() {
+		return structureModifier.withType(double.class);
+	}
+	
+	/**
+	 * Retrieves a read/write structure for every String field.
+	 * @return A modifier for every String field.
+	 */
+	public StructureModifier<String> getStrings() {
+		return structureModifier.withType(String.class);
+	}
+	
+	/**
+	 * Retrieves a read/write structure for every String array field.
+	 * @return A modifier for every String array field.
+	 */
+	public StructureModifier<String[]> getStringArrays() {
+		return structureModifier.withType(String[].class);
+	}
+	
+	/**
+	 * Retrieves a read/write structure for every byte array field.
+	 * @return A modifier for every byte array field.
+	 */
+	public StructureModifier<byte[]> getByteArrays() {
+		return structureModifier.withType(byte[].class);
+	}
+	
 	/**
 	 * Retrieves a read/write structure for ItemStack.
 	 * <p>
@@ -145,22 +203,8 @@ public class PacketContainer implements Serializable {
 	 */
 	public StructureModifier<ItemStack> getItemModifier() {
 		// Convert to and from the Bukkit wrapper
-		return structureModifier.<ItemStack>withType(net.minecraft.server.ItemStack.class, 
+		return structureModifier.<ItemStack>withType(
-				getIgnoreNull(new EquivalentConverter<ItemStack>() {
+				net.minecraft.server.ItemStack.class, BukkitConverters.getItemStackConverter());
-			public Object getGeneric(ItemStack specific) {
-				return toStackNMS(specific);
-			}
-			
-			@Override
-			public ItemStack getSpecific(Object generic) {
-				return new CraftItemStack((net.minecraft.server.ItemStack) generic);
-			}
-			
-			@Override
-			public Class<ItemStack> getSpecificType() {
-				return ItemStack.class;
-			}
-		}));
 	}
 	
 	/**
@@ -171,17 +215,21 @@ public class PacketContainer implements Serializable {
 	 * @return A modifier for ItemStack array fields.
 	 */
 	public StructureModifier<ItemStack[]> getItemArrayModifier() {
+		
+		final EquivalentConverter<ItemStack> stackConverter = BukkitConverters.getItemStackConverter();
+		
 		// Convert to and from the Bukkit wrapper
 		return structureModifier.<ItemStack[]>withType(
 				net.minecraft.server.ItemStack[].class, 
-				getIgnoreNull(new EquivalentConverter<ItemStack[]>() {
+				BukkitConverters.getIgnoreNull(new EquivalentConverter<ItemStack[]>() {
 					
-			public Object getGeneric(ItemStack[] specific) {
+			public Object getGeneric(Class<?>genericType, ItemStack[] specific) {
 				net.minecraft.server.ItemStack[] result = new net.minecraft.server.ItemStack[specific.length];
 				
 				// Unwrap every item
 				for (int i = 0; i < result.length; i++) {
-					result[i] = toStackNMS(specific[i]);
+					result[i] = (net.minecraft.server.ItemStack) stackConverter.getGeneric(
+							net.minecraft.server.ItemStack.class, specific[i]); 
 				}
 				return result;
 			}
@@ -193,7 +241,7 @@ public class PacketContainer implements Serializable {
 				
 				// Add the wrapper
 				for (int i = 0; i < result.length; i++) {
-					result[i] = new CraftItemStack(input[i]);
+					result[i] = stackConverter.getSpecific(input[i]);
 				}
 				return result;
 			}
@@ -205,20 +253,6 @@ public class PacketContainer implements Serializable {
 		}));
 	}
 	
-	/**
-	 * Convert an item stack to the NMS equivalent.
-	 * @param stack - Bukkit stack to convert.
-	 * @return A bukkit stack.
-	 */
-	private net.minecraft.server.ItemStack toStackNMS(ItemStack stack) {
-		// We must be prepared for an object that simply implements ItemStcak
-		if (stack instanceof CraftItemStack) {
-			return ((CraftItemStack) stack).getHandle();
-		} else {
-			return (new CraftItemStack(stack)).getHandle();
-		}
-	}
-	
 	/**
 	 * Retrieves a read/write structure for the world type enum.
 	 * <p>
@@ -227,33 +261,21 @@ public class PacketContainer implements Serializable {
 	 * @return A modifier for world type fields.
 	 */
 	public StructureModifier<WorldType> getWorldTypeModifier() {
-	
-		if (!hasWorldType) {
-			// We couldn't find the Minecraft equivalent
-			return structureModifier.withType(null);
-		}
-		
 		// Convert to and from the Bukkit wrapper
 		return structureModifier.<WorldType>withType(
 				net.minecraft.server.WorldType.class, 
-				getIgnoreNull(new EquivalentConverter<WorldType>() {
+				BukkitConverters.getWorldTypeConverter());
-					
-			@Override
-			public Object getGeneric(WorldType specific) {
-				return net.minecraft.server.WorldType.getType(specific.getName());
 	}
 	
-			@Override
+	/**
-			public WorldType getSpecific(Object generic) {
+	 * Retrieves a read/write structure for data watchers.
-				net.minecraft.server.WorldType type = (net.minecraft.server.WorldType) generic;
+	 * @return A modifier for data watchers.
-				return WorldType.getByName(type.name());
+	 */
-			}
+	public StructureModifier<WrappedDataWatcher> getDataWatcherModifier() {
-			
+		// Convert to and from the Bukkit wrapper
-			@Override
+		return structureModifier.<WrappedDataWatcher>withType(
-			public Class<WorldType> getSpecificType() {
+				net.minecraft.server.DataWatcher.class, 
-				return WorldType.class;
+				BukkitConverters.getDataWatcherConverter());
-			}
-		}));
 	}
 	
 	/**
@@ -267,89 +289,54 @@ public class PacketContainer implements Serializable {
 	 * @return A modifier entity types.
 	 */
 	public StructureModifier<Entity> getEntityModifier(World world) {
-	
-		final Object worldServer = ((CraftWorld) world).getHandle();
-		final Class<?> nmsEntityClass = net.minecraft.server.Entity.class;
-
-		if (getEntity == null)
-			getEntity = FuzzyReflection.fromObject(worldServer).getMethodByParameters(
-					"getEntity", nmsEntityClass, new Class[] { int.class });
-		
 		// Convert to and from the Bukkit wrapper
 		return structureModifier.<Entity>withType(
-				int.class, 
+				int.class, BukkitConverters.getEntityConverter(world));
-				getIgnoreNull(new EquivalentConverter<Entity>() {
-					
-			@Override
-			public Object getGeneric(Entity specific) {
-				// Simple enough
-				return specific.getEntityId();
 	}
 	
-			@Override
+	/**
-			public Entity getSpecific(Object generic) {
+	 * Retrieves a read/write structure for chunk positions.
-				try {
+	 * @return A modifier for a ChunkPosition.
-					net.minecraft.server.Entity nmsEntity = (net.minecraft.server.Entity) 
+	 */
-							getEntity.invoke(worldServer, generic);
+	public StructureModifier<ChunkPosition> getPositionModifier() {
-					Integer id = (Integer) generic;
+		// Convert to and from the Bukkit wrapper
-					
+		return structureModifier.withType(
-					// Attempt to get the Bukkit entity
+				net.minecraft.server.ChunkPosition.class,
-					if (nmsEntity != null) {
+				ChunkPosition.getConverter());
-						return nmsEntity.getBukkitEntity();
-					} else {
-						Server server = Bukkit.getServer();
-						
-						// Maybe it's a player that has just logged in? Try a search
-						if (server != null) {
-							for (Player player : server.getOnlinePlayers()) {
-								if (player.getEntityId() == id) {
-									return player;
-								}
-							}
 	}
 	
-						return null;
+	/**
+	 * Retrieves a read/write structure for collections of chunk positions.
+	 * <p>
+	 * This modifier will automatically marshall between the visible ProtocolLib ChunkPosition and the
+	 * internal Minecraft ChunkPosition.
+	 * @return A modifier for ChunkPosition list fields.
+	 */
+	public StructureModifier<List<ChunkPosition>> getPositionCollectionModifier() {
+		// Convert to and from the ProtocolLib wrapper
+		return structureModifier.withType(
+			Collection.class,
+			BukkitConverters.getListConverter(
+					net.minecraft.server.ChunkPosition.class, 
+					ChunkPosition.getConverter())
+		);
 	}
 	
-				} catch (IllegalArgumentException e) {
+	/**
-					throw new RuntimeException("Incorrect arguments detected.", e);
+	 * Retrieves a read/write structure for collections of watchable objects.
-				} catch (IllegalAccessException e) {
+	 * <p>
-					throw new RuntimeException("Cannot read field due to a security limitation.", e);
+	 * This modifier will automatically marshall between the visible WrappedWatchableObject and the
-				} catch (InvocationTargetException e) {
+	 * internal Minecraft WatchableObject.
-					throw new RuntimeException("Error occured in Minecraft method.", e.getCause());
+	 * @return A modifier for watchable object list fields.
-				}
+	 */
-			}
+	public StructureModifier<List<WrappedWatchableObject>> getWatchableCollectionModifier() {
-			
+		// Convert to and from the ProtocolLib wrapper
-			@Override
+		return structureModifier.withType(
-			public Class<Entity> getSpecificType() {
+			Collection.class,
-				return Entity.class;
+			BukkitConverters.getListConverter(
-			}
+					net.minecraft.server.WatchableObject.class, 
-		}));
+					BukkitConverters.getWatchableObjectConverter())
-	}
+		);
-	
-	private <TType> EquivalentConverter<TType> getIgnoreNull(final EquivalentConverter<TType> delegate) {
-		// Automatically wrap all parameters to the delegate with a NULL check
-		return new EquivalentConverter<TType>() {
-			public Object getGeneric(TType specific) {
-				if (specific != null)
-					return delegate.getGeneric(specific);
-				else
-					return null;
-			}
-			
-			@Override
-			public TType getSpecific(Object generic) {
-				if (generic != null)
-					return delegate.getSpecific(generic);
-				else
-					return null;
-			}
-			
-			@Override
-			public Class<TType> getSpecificType() {
-				return delegate.getSpecificType();
-			}
-		};
 	}
 	
 	/**

ProtocolLib/src/main/java/com/comphenix/protocol/injector/EntityUtilities.java

@@ -27,6 +27,8 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
+import net.minecraft.server.EntityTrackerEntry;
+
 import org.bukkit.World;
 import org.bukkit.craftbukkit.CraftWorld;
 import org.bukkit.entity.Entity;
@@ -83,8 +85,51 @@ class EntityUtilities {
 	 *
 	 */
 	public static void updateEntity(Entity entity, List<Player> observers) throws FieldAccessException {
+		try {
+			//EntityTrackerEntry trackEntity = (EntityTrackerEntry) tracker.trackedEntities.get(entity.getEntityId());
+			Object trackerEntry = getEntityTrackerEntry(entity.getWorld(), entity.getEntityId());
 
-		World world = entity.getWorld();
+			if (trackedPlayersField == null) {
+				// This one is fairly easy
+				trackedPlayersField = FuzzyReflection.fromObject(trackerEntry).getFieldByType("java\\.util\\..*");
+			}
+			
+			// Phew, finally there.
+			Collection<?> trackedPlayers = (Collection<?>) FieldUtils.readField(trackedPlayersField, trackerEntry, false);
+			List<Object> nmsPlayers = unwrapBukkit(observers);
+			
+			// trackEntity.trackedPlayers.clear();
+			trackedPlayers.removeAll(nmsPlayers);
+			
+			// We have to rely on a NAME once again. Damn it.
+			if (scanPlayersMethod == null) {
+				scanPlayersMethod = trackerEntry.getClass().getMethod("scanPlayers", List.class);
+			}
+			
+			//trackEntity.scanPlayers(server.players);
+			scanPlayersMethod.invoke(trackerEntry, nmsPlayers);
+			
+		} catch (IllegalArgumentException e) {
+			throw e;
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Security limitation prevents access to 'get' method in IntHashMap", e);
+		} catch (InvocationTargetException e) {
+			throw new RuntimeException("Exception occurred in Minecraft.", e);
+		} catch (SecurityException e) {
+			throw new FieldAccessException("Security limitation prevents access to 'scanPlayers' method in trackerEntry.", e);
+		} catch (NoSuchMethodException e) {
+			throw new FieldAccessException("Canot find 'scanPlayers' method. Is ProtocolLib up to date?", e);
+		}
+	}
+	
+	/**
+	 * Retrieve the entity tracker entry given a ID.
+	 * @param world - world server.
+	 * @param entityID - entity ID.
+	 * @return The entity tracker entry.
+	 * @throws FieldAccessException 
+	 */
+	private static Object getEntityTrackerEntry(World world, int entityID) throws FieldAccessException, IllegalArgumentException, IllegalAccessException, InvocationTargetException {
 		Object worldServer = ((CraftWorld) world).getHandle();
 
 		// We have to rely on the class naming here.
@@ -149,40 +194,36 @@ class EntityUtilities {
 			}
 		}
 		
+		// Wrap exceptions
 		try {
-			//EntityTrackerEntry trackEntity = (EntityTrackerEntry) tracker.trackedEntities.get(entity.getEntityId());
+			return hashGetMethod.invoke(trackedEntities, entityID);
-			 Object trackerEntry = hashGetMethod.invoke(trackedEntities, entity.getEntityId());
-
-			if (trackedPlayersField == null) {
-				// This one is fairly easy
-				trackedPlayersField = FuzzyReflection.fromObject(trackerEntry).getFieldByType("java\\.util\\..*");
-			}
-			
-			// Phew, finally there.
-			Collection<?> trackedPlayers = (Collection<?>) FieldUtils.readField(trackedPlayersField, trackerEntry, false);
-			List<Object> nmsPlayers = unwrapBukkit(observers);
-			
-			// trackEntity.trackedPlayers.clear();
-			trackedPlayers.removeAll(nmsPlayers);
-			
-			// We have to rely on a NAME once again. Damn it.
-			if (scanPlayersMethod == null) {
-				scanPlayersMethod = trackerEntry.getClass().getMethod("scanPlayers", List.class);
-			}
-			
-			//trackEntity.scanPlayers(server.players);
-			scanPlayersMethod.invoke(trackerEntry, nmsPlayers);
-			
 		} catch (IllegalArgumentException e) {
 			throw e;
 		} catch (IllegalAccessException e) {
 			throw new FieldAccessException("Security limitation prevents access to 'get' method in IntHashMap", e);
 		} catch (InvocationTargetException e) {
 			throw new RuntimeException("Exception occurred in Minecraft.", e);
-		} catch (SecurityException e) {
+		}
-			throw new FieldAccessException("Security limitation prevents access to 'scanPlayers' method in trackerEntry.", e);
+	}
-		} catch (NoSuchMethodException e) {
+	
-			throw new FieldAccessException("Canot find 'scanPlayers' method. Is ProtocolLib up to date?", e);
+	/**
+	 * Retrieve entity from a ID, even it it's newly created.
+	 * @return The asssociated entity.
+	 * @throws FieldAccessException Reflection error.
+	 */
+	public static Entity getEntityFromID(World world, int entityID) throws FieldAccessException {
+		try {
+			EntityTrackerEntry trackerEntry = (EntityTrackerEntry) getEntityTrackerEntry(world, entityID);
+			
+			// Handle NULL cases
+			if (trackerEntry != null && trackerEntry.tracker != null) {
+				return trackerEntry.tracker.getBukkitEntity();
+			} else {
+				return null;
+			}
+			
+		} catch (Exception e) {
+			throw new FieldAccessException("Cannot find entity from ID.", e);
 		}
 	}
 	

ProtocolLib/src/main/java/com/comphenix/protocol/injector/PacketFilterManager.java

@@ -34,6 +34,7 @@ import net.sf.cglib.proxy.MethodInterceptor;
 import net.sf.cglib.proxy.MethodProxy;
 
 import org.bukkit.Server;
+import org.bukkit.World;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
@@ -565,6 +566,11 @@ public final class PacketFilterManager implements ProtocolManager, ListenerInvok
 		EntityUtilities.updateEntity(entity, observers);
 	}
 	
+	@Override
+	public Entity getEntityFromID(World container, int id) throws FieldAccessException {
+		return EntityUtilities.getEntityFromID(container, id);
+	}
+	
 	/**
 	 * Initialize the packet injection for every player.
 	 * @param players - list of players to inject. 

ProtocolLib/src/main/java/com/comphenix/protocol/reflect/EquivalentConverter.java

@@ -24,8 +24,25 @@ package com.comphenix.protocol.reflect;
  * @param <TType> The specific type.
  */
 public interface EquivalentConverter<TType> {
+	/**
+	 * Retrieve a copy of the specific type using an instance of the generic type.
+	 * @param generic - the generic type.
+	 * @return The new specific type.
+	 */
 	public TType getSpecific(Object generic);
-	public Object getGeneric(TType specific);
+	
+	/**
+	 * Retrieve a copy of the generic type from a specific type.
+	 * @param genericType - class or super class of the generic type.
+	 * @param specific - the specific type we need to copy.
+	 * @return A copy of the specific type.
+	 */
+	public Object getGeneric(Class<?> genericType, TType specific);
+	
+	/**
+	 * Due to type erasion, we need to explicitly keep a reference to the specific type.
+	 * @return The specific type.
+	 */
 	public Class<TType> getSpecificType();
 }
 

ProtocolLib/src/main/java/com/comphenix/protocol/reflect/ObjectCloner.java

@@ -66,8 +66,10 @@ public class ObjectCloner {
 		// Copy every field
 		try {
 			for (int i = 0; i < modifierSource.size(); i++) {
+				if (!modifierDest.isReadOnly(i)) {
 					Object value = modifierSource.read(i);
 					modifierDest.write(i, value);
+				}
 				
 				// System.out.println(String.format("Writing value %s to %s", 
 				//		value, modifier.getFields().get(i).getName()));

ProtocolLib/src/main/java/com/comphenix/protocol/reflect/StructureModifier.java

@@ -61,6 +61,17 @@ public class StructureModifier<TField> {
 	// Whether or subclasses should handle conversion
 	protected boolean customConvertHandling;
 	
+	// Whether or not to automatically compile the structure modifier
+	protected boolean useStructureCompiler;
+
+	/**
+	 * Creates a structure modifier.
+	 * @param targetType - the structure to modify.
+	 */
+	public StructureModifier(Class targetType) {
+		this(targetType, null, true);
+	}
+	
 	/**
 	 * Creates a structure modifier.
 	 * @param targetType - the structure to modify.
@@ -68,10 +79,22 @@ public class StructureModifier<TField> {
 	 * @param requireDefault - whether or not we will be using writeDefaults().
 	 */
 	public StructureModifier(Class targetType, Class superclassExclude, boolean requireDefault) {
+		this(targetType, superclassExclude, requireDefault, true);
+	}
+	
+	/**
+	 * Creates a structure modifier.
+	 * @param targetType - the structure to modify.
+	 * @param superclassExclude - a superclass to exclude.
+	 * @param requireDefault - whether or not we will be using writeDefaults().
+	 * @param useStructureModifier - whether or not to automatically compile this structure modifier.
+	 */
+	public StructureModifier(Class targetType, Class superclassExclude, boolean requireDefault, boolean useStructureCompiler) {
 		List<Field> fields = getFields(targetType, superclassExclude);
 		Map<Field, Integer> defaults = requireDefault ? generateDefaultFields(fields) : new HashMap<Field, Integer>();
 		
-		initialize(targetType, Object.class, fields, defaults, null, new ConcurrentHashMap<Class, StructureModifier>());
+		initialize(targetType, Object.class, fields, defaults, null, 
+				   new ConcurrentHashMap<Class, StructureModifier>(), useStructureCompiler);
 	}
 	
 	/**
@@ -87,7 +110,8 @@ public class StructureModifier<TField> {
 	 */
 	protected void initialize(StructureModifier<TField> other) {
 		initialize(other.targetType, other.fieldType, other.data, 
-				   other.defaultFields, other.converter, other.subtypeCache);
+				   other.defaultFields, other.converter, other.subtypeCache, 
+				   other.useStructureCompiler);
 	}
 	
 	/**
@@ -102,12 +126,31 @@ public class StructureModifier<TField> {
 	protected void initialize(Class targetType, Class fieldType, 
 			  List<Field> data, Map<Field, Integer> defaultFields,
 			  EquivalentConverter<TField> converter, Map<Class, StructureModifier> subTypeCache) {
+		initialize(targetType, fieldType, data, defaultFields, converter, subTypeCache, true);
+	}
+	
+	/**
+	 * Initialize every field of this class.
+	 * @param targetType - type of the object we're reading and writing from.
+	 * @param fieldType - the common type of the fields we're modifying.
+	 * @param data - list of fields to modify.
+	 * @param defaultFields - list of fields that will be automatically initialized.
+	 * @param converter - converts between the common field type and the actual type the consumer expects.
+	 * @param subTypeCache - a structure modifier cache.
+	 * @param useStructureModifier - whether or not to automatically compile this structure modifier.
+	 */
+	protected void initialize(Class targetType, Class fieldType, 
+			  List<Field> data, Map<Field, Integer> defaultFields,
+			  EquivalentConverter<TField> converter, Map<Class, StructureModifier> subTypeCache,
+			  boolean useStructureCompiler) {
+		
 		this.targetType = targetType;
 		this.fieldType = fieldType;
 		this.data = data;
 		this.defaultFields = defaultFields;
 		this.converter = converter;
 		this.subtypeCache = subTypeCache;
+		this.useStructureCompiler = useStructureCompiler;
 	}
 	
 	/**
@@ -152,6 +195,52 @@ public class StructureModifier<TField> {
 		}
 	}
 	
+	/**
+	 * Determine whether or not a field is read-only (final).
+	 * @param fieldIndex - index of the field.
+	 * @return TRUE if the field by the given index is read-only, FALSE otherwise.
+	 */
+	public boolean isReadOnly(int fieldIndex) {
+		if (fieldIndex < 0 || fieldIndex >= data.size())
+			new IllegalArgumentException("Index parameter is not within [0 - " + data.size() + ")");
+		
+		return Modifier.isFinal(data.get(fieldIndex).getModifiers());
+	}
+	
+	/**
+	 * Set whether or not a field should be treated as read only.
+	 * <p>
+	 * Note that changing the read-only state to TRUE will only work if the current
+	 * field was recently read-only or the current structure modifier hasn't been compiled yet.
+	 * 
+	 * @param fieldIndex - index of the field.
+	 * @param value - TRUE if this field should be read only, FALSE otherwise.
+	 * @throws FieldAccessException If we cannot modify the read-only status.
+	 */
+	public void setReadOnly(int fieldIndex, boolean value) throws FieldAccessException {
+		if (fieldIndex < 0 || fieldIndex >= data.size())
+			new IllegalArgumentException("Index parameter is not within [0 - " + data.size() + ")");
+
+		try {
+			StructureModifier.setFinalState(data.get(fieldIndex), value);
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Cannot write read only status due to a security limitation.", e);
+		}
+	}
+	
+	/**
+	 * Alter the final status of a field.
+	 * @param field - the field to change.
+	 * @param isReadOnly - TRUE if the field should be read only, FALSE otherwise.
+	 * @throws IllegalAccessException If an error occured.
+	 */
+	protected static void setFinalState(Field field, boolean isReadOnly) throws IllegalAccessException {
+	    if (isReadOnly)
+	    	FieldUtils.writeField((Object) field, "modifiers", field.getModifiers() | Modifier.FINAL, true);
+	    else
+	    	FieldUtils.writeField((Object) field, "modifiers", field.getModifiers() & ~Modifier.FINAL, true);
+	}
+	
 	/**
 	 * Writes the value of a field given its index.
 	 * @param fieldIndex - index of the field.
@@ -167,7 +256,7 @@ public class StructureModifier<TField> {
 			throw new IllegalStateException("Cannot write to a NULL target.");
 		
 		// Use the converter, if it exists
-		Object obj = needConversion() ? converter.getGeneric(value) : value;
+		Object obj = needConversion() ? converter.getGeneric(getFieldType(fieldIndex), value) : value;
 		
 		try {
 			FieldUtils.writeField(data.get(fieldIndex), target, obj, true);
@@ -179,6 +268,15 @@ public class StructureModifier<TField> {
 		return this;
 	}
 	
+	/**
+	 * Retrieve the type of a specified field.
+	 * @param index - the index.
+	 * @return The type of the given field.
+	 */
+	protected Class<?> getFieldType(int index) {
+		return data.get(index).getType();
+	}
+	
 	/**
 	 * Whether or not we should use the converter instance.
 	 * @return TRUE if we should, FALSE otherwise.
@@ -281,7 +379,7 @@ public class StructureModifier<TField> {
 				subtypeCache.put(fieldType, result);
 				
 				// Automatically compile the structure modifier
-				if (BackgroundCompiler.getInstance() != null) 
+				if (useStructureCompiler && BackgroundCompiler.getInstance() != null) 
 					BackgroundCompiler.getInstance().scheduleCompilation(subtypeCache, fieldType);
 			}
 		}
@@ -353,7 +451,8 @@ public class StructureModifier<TField> {
 		
 		StructureModifier<T> result = new StructureModifier<T>();
 		result.initialize(targetType, fieldType, filtered, defaults, 
-						  converter, new ConcurrentHashMap<Class, StructureModifier>());
+						  converter, new ConcurrentHashMap<Class, StructureModifier>(), 
+						  useStructureCompiler);
 		return result;
 	}
 	
@@ -366,7 +465,7 @@ public class StructureModifier<TField> {
 		StructureModifier<TField> copy = new StructureModifier<TField>();
 		
 		// Create a new instance
-		copy.initialize(targetType, fieldType, data, defaultFields, converter, subtypeCache);
+		copy.initialize(this);
 		copy.target = target;
 		return copy;
 	}
@@ -424,9 +523,10 @@ public class StructureModifier<TField> {
 		
 		for (Field field : fields) {
 			Class<?> type = field.getType();
+			int modifier = field.getModifiers();
 			
-			// First, ignore primitive fields
+			// First, ignore primitive fields and final fields
-			if (!type.isPrimitive()) {
+			if (!type.isPrimitive() && !Modifier.isFinal(modifier)) {
 				// Next, see if we actually can generate a default value
 				if (generator.getDefault(type) != null) {
 					// If so, require it
@@ -449,9 +549,9 @@ public class StructureModifier<TField> {
 		for (Field field : FuzzyReflection.fromClass(type, true).getFields()) {
 			int mod = field.getModifiers();
 			
-			// Ignore static, final and "abstract packet" fields
+			// Ignore static and "abstract packet" fields
-			if (!Modifier.isFinal(mod) && !Modifier.isStatic(mod) && (
+			if (!Modifier.isStatic(mod) && 
-					superclassExclude == null || !field.getDeclaringClass().equals(superclassExclude)
+					(superclassExclude == null || !field.getDeclaringClass().equals(superclassExclude)
 				)) {
 				
 				result.add(field);

ProtocolLib/src/main/java/com/comphenix/protocol/reflect/compiler/CompiledStructureModifier.java

@@ -19,10 +19,12 @@ package com.comphenix.protocol.reflect.compiler;
 
 import java.lang.reflect.Field;
 import java.util.Map;
+import java.util.Set;
 
 import com.comphenix.protocol.reflect.FieldAccessException;
 import com.comphenix.protocol.reflect.StructureModifier;
 import com.comphenix.protocol.reflect.instances.DefaultInstances;
+import com.google.common.collect.Sets;
 
 /**
  * Represents a compiled structure modifier.
@@ -34,11 +36,33 @@ public abstract class CompiledStructureModifier<TField> extends StructureModifie
 	// Used to compile instances of structure modifiers
 	protected StructureCompiler compiler;
 	
+	// Fields that originally were read only
+	private Set<Integer> exempted;
+	
 	public CompiledStructureModifier() {
 		super();
 		customConvertHandling = true;
 	}
 	
+	@Override
+	public void setReadOnly(int fieldIndex, boolean value) throws FieldAccessException {
+		// We can remove the read-only status
+		if (isReadOnly(fieldIndex) && !value) {
+			if (exempted == null)
+				exempted = Sets.newHashSet();
+			exempted.add(fieldIndex);
+		}
+		
+		// We can only make a certain kind of field read only
+		if (!isReadOnly(fieldIndex) && value) {
+			if (exempted == null || !exempted.contains(fieldIndex)) {
+				throw new IllegalStateException("Cannot make compiled field " + fieldIndex + " read only.");
+			}
+		}
+		
+		super.setReadOnly(fieldIndex, value);
+	}
+	
 	// Speed up the default writer
 	@SuppressWarnings("unchecked")
 	@Override
@@ -84,7 +108,7 @@ public abstract class CompiledStructureModifier<TField> extends StructureModifie
 	@Override
 	public StructureModifier<TField> write(int index, Object value) throws FieldAccessException {
 		if (converter != null)
-			value = converter.getGeneric((TField) value);
+			value = converter.getGeneric(getFieldType(index), (TField) value);
 		return writeGenerated(index, value);
 	}
 	

ProtocolLib/src/main/java/com/comphenix/protocol/reflect/compiler/StructureCompiler.java

@@ -272,6 +272,10 @@ public final class StructureCompiler {
 		return Modifier.isPublic(field.getModifiers());
 	}
 	
+	private boolean isNonFinal(Field field) {
+		return !Modifier.isFinal(field.getModifiers());
+	}
+	
 	private void createFields(ClassWriter cw, String targetSignature) {
 		FieldVisitor typedField = cw.visitField(Opcodes.ACC_PRIVATE, "typedTarget", targetSignature, null, null);
 		typedField.visitEnd();
@@ -305,7 +309,8 @@ public final class StructureCompiler {
 		
 		for (int i = 0; i < fields.size(); i++) {
 			
-			Class<?> outputType = fields.get(i).getType();
+			Field field = fields.get(i);
+			Class<?> outputType = field.getType();
 			Class<?> inputType = Primitives.wrap(outputType);
 			String typeDescriptor = Type.getDescriptor(outputType);
 			String inputPath = inputType.getName().replace('.', '/');
@@ -318,8 +323,8 @@ public final class StructureCompiler {
 			else
 				mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
 			
-			// Only write to public fields
+			// Only write to public non-final fields
-			if (isPublic(fields.get(i))) {
+			if (isPublic(field) && isNonFinal(field)) {
 				mv.visitVarInsn(Opcodes.ALOAD, 3);
 				mv.visitVarInsn(Opcodes.ALOAD, 2);
 				
@@ -328,7 +333,7 @@ public final class StructureCompiler {
 				else
 					boxingHelper.unbox(Type.getType(outputType));
 				
-				mv.visitFieldInsn(Opcodes.PUTFIELD, targetName, fields.get(i).getName(), typeDescriptor);
+				mv.visitFieldInsn(Opcodes.PUTFIELD, targetName, field.getName(), typeDescriptor);
 			
 			} else {
 				// Use reflection. We don't have a choice, unfortunately.
@@ -386,7 +391,9 @@ public final class StructureCompiler {
 		mv.visitTableSwitchInsn(0, fields.size() - 1, errorLabel, labels);
 		
 		for (int i = 0; i < fields.size(); i++) {
-			Class<?> outputType = fields.get(i).getType();
+			
+			Field field = fields.get(i);
+			Class<?> outputType = field.getType();
 			String typeDescriptor = Type.getDescriptor(outputType);
 			
 			mv.visitLabel(labels[i]);
@@ -398,9 +405,9 @@ public final class StructureCompiler {
 				mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
 			
 			// Note that byte code cannot access non-public fields
-			if (isPublic(fields.get(i))) {
+			if (isPublic(field)) {
 				mv.visitVarInsn(Opcodes.ALOAD, 2);
-				mv.visitFieldInsn(Opcodes.GETFIELD, targetName, fields.get(i).getName(), typeDescriptor);
+				mv.visitFieldInsn(Opcodes.GETFIELD, targetName, field.getName(), typeDescriptor);
 				
 				boxingHelper.box(Type.getType(outputType));
 			} else {

ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/BukkitConverters.java

@@ -0,0 +1,281 @@
+package com.comphenix.protocol.wrappers;
+
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import net.minecraft.server.DataWatcher;
+import net.minecraft.server.WatchableObject;
+
+import org.bukkit.World;
+import org.bukkit.WorldType;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.entity.Entity;
+import org.bukkit.inventory.ItemStack;
+
+import com.comphenix.protocol.ProtocolLibrary;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.reflect.EquivalentConverter;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.instances.DefaultInstances;
+
+/**
+ * Contains several useful equivalent converters for normal Bukkit types.
+ * 
+ * @author Kristian
+ */
+public class BukkitConverters {
+	// Check whether or not certain classes exists
+	private static boolean hasWorldType = false;
+	
+	static {
+		try {
+			Class.forName("net.minecraft.server.WorldType");
+			hasWorldType = true;
+		} catch (ClassNotFoundException e) {
+		}
+	}
+	
+	public static <T> EquivalentConverter<List<T>> getListConverter(final Class<?> genericItemType, final EquivalentConverter<T> itemConverter) {
+		// Convert to and from the wrapper
+		return getIgnoreNull(new EquivalentConverter<List<T>>() {
+				@SuppressWarnings("unchecked")
+				@Override
+				public List<T> getSpecific(Object generic) {
+					if (generic instanceof Collection) {
+						List<T> items = new ArrayList<T>();
+					
+						// Copy everything to a new list
+						for (Object item : (Collection<Object>) generic) {
+							T result = itemConverter.getSpecific(item);
+							
+							if (item != null)
+								items.add(result);
+						}
+						return items;
+					}
+					
+					// Not valid
+					return null;
+				}
+
+				@SuppressWarnings("unchecked")
+				@Override
+				public Object getGeneric(Class<?> genericType, List<T> specific) {
+					Collection<Object> newContainer = (Collection<Object>) DefaultInstances.DEFAULT.getDefault(genericType);
+					
+					// Convert each object
+					for (T position : specific) {
+						Object converted = itemConverter.getGeneric(genericItemType, position);
+						
+						if (position == null)
+							newContainer.add(null);
+						else if (converted != null)
+							newContainer.add(converted);
+					}
+					return newContainer;
+				}
+
+				@SuppressWarnings("unchecked")
+				@Override
+				public Class<List<T>> getSpecificType() {
+					// Damn you Java
+					Class<?> dummy = List.class;
+					return (Class<List<T>>) dummy;
+				}
+			}
+		);
+	}
+	
+	/**
+	 * Retrieve a converter for watchable objects and the respective wrapper.
+	 * @return A watchable object converter.
+	 */
+	public static EquivalentConverter<WrappedWatchableObject> getWatchableObjectConverter() {
+		return getIgnoreNull(new EquivalentConverter<WrappedWatchableObject>() {
+			@Override
+			public Object getGeneric(Class<?> genericType, WrappedWatchableObject specific) {
+				return specific.getHandle();
+			}
+			
+			public WrappedWatchableObject getSpecific(Object generic) {
+				if (generic instanceof WatchableObject)
+					return new WrappedWatchableObject((WatchableObject) generic);
+				else if (generic instanceof WrappedWatchableObject)
+					return (WrappedWatchableObject) generic;
+				else
+					throw new IllegalArgumentException("Unrecognized type " + generic.getClass());
+			};
+			
+			@Override
+			public Class<WrappedWatchableObject> getSpecificType() {
+				return WrappedWatchableObject.class;
+			}
+		});
+	}
+	
+	/**
+	 * Retrieve a converter for the NMS DataWatcher class and our wrapper.
+	 * @return A DataWatcher converter.
+	 */
+	public static EquivalentConverter<WrappedDataWatcher> getDataWatcherConverter() {
+		return getIgnoreNull(new EquivalentConverter<WrappedDataWatcher>() {
+			@Override
+			public Object getGeneric(Class<?> genericType, WrappedDataWatcher specific) {
+				return specific.getHandle();
+			}
+			
+			@Override
+			public WrappedDataWatcher getSpecific(Object generic) {
+				if (generic instanceof DataWatcher)
+					return new WrappedDataWatcher((DataWatcher) generic);
+				else if (generic instanceof WrappedDataWatcher)
+					return (WrappedDataWatcher) generic;
+				else
+					throw new IllegalArgumentException("Unrecognized type " + generic.getClass());
+			}
+			
+			@Override
+			public Class<WrappedDataWatcher> getSpecificType() {
+				return WrappedDataWatcher.class;
+			}
+		});
+	}
+	
+	/**
+	 * Retrieve a converter for Bukkit's world type enum and the NMS equivalent.
+	 * @return A world type enum converter.
+	 */
+	public static EquivalentConverter<WorldType> getWorldTypeConverter() {
+		// Check that we can actually use this converter
+		if (!hasWorldType)
+			return null;
+		
+		return getIgnoreNull(new EquivalentConverter<WorldType>() {
+			@Override
+			public Object getGeneric(Class<?> genericType, WorldType specific) {
+				return net.minecraft.server.WorldType.getType(specific.getName());
+			}
+			
+			@Override
+			public WorldType getSpecific(Object generic) {
+				net.minecraft.server.WorldType type = (net.minecraft.server.WorldType) generic;
+				return WorldType.getByName(type.name());
+			}
+			
+			@Override
+			public Class<WorldType> getSpecificType() {
+				return WorldType.class;
+			}
+		});
+	}
+	
+	/**
+	 * Retrieve a converter for NMS entities and Bukkit entities.
+	 * @param world - the current world.
+	 * @return A converter between the underlying NMS entity and Bukkit's wrapper.
+	 */
+	public static EquivalentConverter<Entity> getEntityConverter(World world) {
+		final World container = world;
+		final WeakReference<ProtocolManager> managerRef = 
+				new WeakReference<ProtocolManager>(ProtocolLibrary.getProtocolManager());
+
+		return getIgnoreNull(new EquivalentConverter<Entity>() {
+			
+			@Override
+			public Object getGeneric(Class<?> genericType, Entity specific) {
+				// Simple enough
+				return specific.getEntityId();
+			}
+			
+			@Override
+			public Entity getSpecific(Object generic) {
+				try {
+					Integer id = (Integer) generic;
+					
+					// Use the 
+					if (id != null && managerRef.get() != null) {
+						return managerRef.get().getEntityFromID(container, id);
+					} else {
+						return null;
+					}
+					
+				} catch (FieldAccessException e) {
+					throw new RuntimeException("Cannot retrieve entity from ID.", e);
+				}
+			}
+			
+			@Override
+			public Class<Entity> getSpecificType() {
+				return Entity.class;
+			}
+		});
+	}
+	
+	/**
+	 * Retrieve the converter used to convert NMS ItemStacks to Bukkit's ItemStack.
+	 * @return Item stack converter.
+	 */
+	public static EquivalentConverter<ItemStack> getItemStackConverter() {
+		return getIgnoreNull(new EquivalentConverter<ItemStack>() {
+			public Object getGeneric(Class<?> genericType, ItemStack specific) {
+				return toStackNMS(specific);
+			}
+			
+			@Override
+			public ItemStack getSpecific(Object generic) {
+				return new CraftItemStack((net.minecraft.server.ItemStack) generic);
+			}
+			
+			@Override
+			public Class<ItemStack> getSpecificType() {
+				return ItemStack.class;
+			}
+		});
+	}
+	
+	/**
+	 * Convert an item stack to the NMS equivalent.
+	 * @param stack - Bukkit stack to convert.
+	 * @return A bukkit stack.
+	 */
+	private static net.minecraft.server.ItemStack toStackNMS(ItemStack stack) {
+		// We must be prepared for an object that simply implements ItemStcak
+		if (stack instanceof CraftItemStack) {
+			return ((CraftItemStack) stack).getHandle();
+		} else {
+			return (new CraftItemStack(stack)).getHandle();
+		}
+	}
+	
+	/**
+	 * Wraps a given equivalent converter in NULL checks, ensuring that such values are ignored.
+	 * @param delegate - the underlying equivalent converter.
+	 * @return A equivalent converter that ignores NULL values.
+	 */
+	public static <TType> EquivalentConverter<TType> getIgnoreNull(final EquivalentConverter<TType> delegate) {
+		// Automatically wrap all parameters to the delegate with a NULL check
+		return new EquivalentConverter<TType>() {
+			public Object getGeneric(Class<?> genericType, TType specific) {
+				if (specific != null)
+					return delegate.getGeneric(genericType, specific);
+				else
+					return null;
+			}
+			
+			@Override
+			public TType getSpecific(Object generic) {
+				if (generic != null)
+					return delegate.getSpecific(generic);
+				else
+					return null;
+			}
+			
+			@Override
+			public Class<TType> getSpecificType() {
+				return delegate.getSpecificType();
+			}
+		};
+	}
+}

ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/ChunkPosition.java

@@ -0,0 +1,194 @@
+package com.comphenix.protocol.wrappers;
+
+import org.bukkit.util.Vector;
+
+import com.comphenix.protocol.reflect.EquivalentConverter;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.StructureModifier;
+import com.google.common.base.Objects;
+
+/**
+ * Copies a immutable net.minecraft.server.ChunkPosition, which represents a integer 3D vector.
+ * 
+ * @author Kristian
+ */
+public class ChunkPosition {
+	
+	/**
+	 * Represents the null (0, 0, 0) origin.
+	 */
+	public static ChunkPosition ORIGIN = new ChunkPosition(0, 0, 0);
+	
+	// Use protected members, like Bukkit
+	protected final int x;
+	protected final int y;
+	protected final int z;
+	
+	// Used to access a ChunkPosition, in case it's names are changed
+	private static StructureModifier<Integer> intModifier;
+
+	/**
+	 * Construct an immutable 3D vector.
+	 */
+	public ChunkPosition(int x, int y, int z) {
+		this.x = x;
+		this.y = y;
+		this.z = z;
+	}
+	
+	/**
+	 * Construct an immutable integer 3D vector from a mutable Bukkit vector.
+	 * @param vector - the mutable real Bukkit vector to copy.
+	 */
+	public ChunkPosition(Vector vector) {
+		if (vector == null)
+			throw new IllegalArgumentException("Vector cannot be NULL.");
+		this.x = vector.getBlockX();
+		this.y = vector.getBlockY();
+		this.z = vector.getBlockZ();
+	}
+
+	/**
+	 * Convert this instance to an equivalent real 3D vector.
+	 * @return Real 3D vector.
+	 */
+	public Vector toVector() {
+		return new Vector(x, y, z);
+	}
+	
+	/**
+	 * Retrieve the x-coordinate.
+	 * @return X coordinate.
+	 */
+	public int getX() {
+		return x;
+	}
+	
+	/**
+	 * Retrieve the y-coordinate.
+	 * @return Y coordinate.
+	 */
+	public int getY() {
+		return y;
+	}
+	
+	/**
+	 * Retrieve the z-coordinate.
+	 * @return Z coordinate.
+	 */
+	public int getZ() {
+		return z;
+	}
+	
+	/**
+	 * Adds the current position and a given position together, producing a result position.
+	 * @param other - the other position.
+	 * @return The new result position.
+	 */
+	public ChunkPosition add(ChunkPosition other) {
+		if (other == null)
+			throw new IllegalArgumentException("other cannot be NULL");
+		return new ChunkPosition(x + other.x, y + other.y, z + other.z);
+	}
+	
+	/**
+	 * Adds the current position and a given position together, producing a result position.
+	 * @param other - the other position.
+	 * @return The new result position.
+	 */
+	public ChunkPosition subtract(ChunkPosition other) {
+		if (other == null)
+			throw new IllegalArgumentException("other cannot be NULL");
+		return new ChunkPosition(x - other.x, y - other.y, z - other.z);
+	}
+	
+	/**
+	 * Multiply each dimension in the current position by the given factor.
+	 * @param factor - multiplier.
+	 * @return The new result.
+	 */
+	public ChunkPosition multiply(int factor) {
+		return new ChunkPosition(x * factor, y * factor, z * factor);
+	}
+	
+	/**
+	 * Divide each dimension in the current position by the given divisor.
+	 * @param divisor - the divisor.
+	 * @return The new result.
+	 */
+	public ChunkPosition divide(int divisor) {
+		if (divisor == 0)
+			throw new IllegalArgumentException("Cannot divide by null.");
+		return new ChunkPosition(x / divisor, y / divisor, z / divisor);
+	}
+	
+	/**
+	 * Used to convert between NMS ChunkPosition and the wrapper instance.
+	 * @return A new converter.
+	 */
+	public static EquivalentConverter<ChunkPosition> getConverter() {
+		return new EquivalentConverter<ChunkPosition>() {
+			@Override
+			public Object getGeneric(Class<?> genericType, ChunkPosition specific) {
+				return new net.minecraft.server.ChunkPosition(specific.x, specific.z, specific.z);
+			}
+			
+			@Override
+			public ChunkPosition getSpecific(Object generic) {
+				if (generic instanceof net.minecraft.server.ChunkPosition) {
+					net.minecraft.server.ChunkPosition other = (net.minecraft.server.ChunkPosition) generic;
+					
+					try {
+						if (intModifier == null)
+							return new ChunkPosition(other.x, other.y, other.z);
+					} catch (LinkageError e) {
+						// It could happen. If it does, use a structure modifier instead
+						intModifier = new StructureModifier<Object>(other.getClass(), null, false).withType(int.class);
+						
+						// Damn it all
+						if (intModifier.size() < 3) {
+							throw new IllegalStateException("Cannot read class " + other.getClass() + " for its integer fields.");
+						}
+					}
+					
+					if (intModifier.size() >= 3) {
+						try {
+							return new ChunkPosition(intModifier.read(0), intModifier.read(1), intModifier.read(2));
+						} catch (FieldAccessException e) {
+							// This is an exeptional work-around, so we don't want to burden the caller with the messy details
+							throw new RuntimeException("Field access error.", e);
+						} 
+					}
+				}
+				
+				// Otherwise, return NULL
+				return null;
+			}
+
+			// Thanks Java Generics!
+			@Override
+			public Class<ChunkPosition> getSpecificType() {
+				return ChunkPosition.class;
+			}
+		};
+	}
+		
+	@Override
+	public boolean equals(Object obj) {
+		// Fast checks
+		if (this == obj) return true;
+		if (obj == null) return false;
+		
+		// Only compare objects of similar type
+		if (obj instanceof ChunkPosition) {
+			ChunkPosition other = (ChunkPosition) obj;
+			return x == other.x && y == other.y && z == other.z;
+		}
+		return false;
+	}
+	
+	@Override
+	public int hashCode() {
+		return Objects.hashCode(x, y, z);
+	}
+}

ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/WrappedChunkCoordinate.java

@@ -0,0 +1,145 @@
+package com.comphenix.protocol.wrappers;
+
+import com.google.common.base.Objects;
+
+import net.minecraft.server.ChunkCoordinates;
+
+/**
+ * Allows access to a chunk coordinate.
+ * 
+ * @author Kristian
+ */
+public class WrappedChunkCoordinate implements Comparable<WrappedChunkCoordinate> {
+
+	/**
+	 * If TRUE, NULLs should be put before non-null instances of this class.
+	 */
+	private static final boolean LARGER_THAN_NULL = true;
+	
+	protected ChunkCoordinates handle;
+
+	/**
+	 * Create a new empty wrapper.
+	 */
+	public WrappedChunkCoordinate() {
+		this(new ChunkCoordinates());
+	}
+	
+	/**
+	 * Create a wrapper for a specific chunk coordinates.
+	 * @param handle - the NMS chunk coordinates.
+	 */
+	public WrappedChunkCoordinate(ChunkCoordinates handle) {
+		if (handle == null)
+			throw new IllegalArgumentException("handle cannot be NULL");
+		this.handle = handle;
+	}
+	
+	/**
+	 * Create a wrapper with specific values.
+	 * @param x - the x coordinate.
+	 * @param y - the y coordinate.
+	 * @param z - the z coordinate.
+	 */
+	public WrappedChunkCoordinate(int x, int y, int z) {
+		this();
+		setX(x);
+		setY(y);
+		setZ(z);
+	}
+	
+	/**
+	 * Create a chunk coordinate wrapper from a given position.
+	 * @param position - the given position.
+	 */
+	public WrappedChunkCoordinate(ChunkPosition position) {
+		this(position.getX(), position.getY(), position.getZ());
+	}
+	
+	public ChunkCoordinates getHandle() {
+		return handle;
+	}
+	
+	/**
+	 * Retrieve the x coordinate of the underlying coordiate.
+	 * @return The x coordinate.
+	 */
+	public int getX() {
+		return handle.x;
+	}
+	
+	/**
+	 * Set the x coordinate of the underlying coordiate.
+	 * @param newX - the new x coordinate.
+	 */
+	public void setX(int newX) {
+		handle.x = newX;
+	}
+	
+	/**
+	 * Retrieve the y coordinate of the underlying coordiate.
+	 * @return The y coordinate.
+	 */
+	public int getY() {
+		return handle.y;
+	}
+	
+	/**
+	 * Set the y coordinate of the underlying coordiate.
+	 * @param newY - the new y coordinate.
+	 */
+	public void setY(int newY) {
+		handle.y = newY;
+	}
+	
+	/**
+	 * Retrieve the z coordinate of the underlying coordiate.
+	 * @return The z coordinate.
+	 */
+	public int getZ() {
+		return handle.z;
+	}
+	
+	/**
+	 * Create an immutable chunk position from this coordinate.
+	 * @return The new immutable chunk position.
+	 */
+	public ChunkPosition toPosition() {
+		return new ChunkPosition(getX(), getY(), getZ());
+	}
+	
+	/**
+	 * Set the z coordinate of the underlying coordiate.
+	 * @param newZ - the new z coordinate.
+	 */
+	public void setZ(int newZ) {
+		handle.z = newZ;
+	}
+
+	@Override
+	public int compareTo(WrappedChunkCoordinate other) {
+		// We'll handle NULL objects too, unlike ChunkCoordinates
+		if (other.handle == null)
+			return LARGER_THAN_NULL ? -1 : 1;
+		else
+			return handle.compareTo(other.handle);
+	}
+
+	@Override
+	public boolean equals(Object other) {
+		if (other instanceof WrappedChunkCoordinate) {
+			WrappedChunkCoordinate wrapper = (WrappedChunkCoordinate) other;
+			return Objects.equal(handle, wrapper.handle);
+		}
+		
+		// It's tempting to handle the ChunkCoordinate case too, but then
+		// the equals() method won't be commutative, causing a.equals(b) to
+		// be different to b.equals(a).
+		return false;
+	}
+	
+	@Override
+	public int hashCode() {
+		return handle.hashCode();
+	}
+}

ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/WrappedDataWatcher.java

@@ -0,0 +1,506 @@
+package com.comphenix.protocol.wrappers;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import org.bukkit.entity.Entity;
+import org.bukkit.inventory.ItemStack;
+
+import com.comphenix.protocol.injector.BukkitUnwrapper;
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.FieldUtils;
+import com.comphenix.protocol.reflect.FuzzyReflection;
+import com.google.common.base.Objects;
+
+import net.minecraft.server.ChunkCoordinates;
+import net.minecraft.server.DataWatcher;
+import net.minecraft.server.WatchableObject;
+
+/**
+ * Wraps a DataWatcher that is used to transmit arbitrary key-value pairs with a given entity.
+ * 
+ * @author Kristian
+ */
+public class WrappedDataWatcher {
+
+	/**
+	 * Used to assign integer IDs to given types.
+	 */
+	private static Map<Class<?>, Integer> typeMap;
+
+	// Fields
+	private static Field valueMapField;
+	private static Field readWriteLockField;
+	
+	// Methods
+	private static Method createKeyValueMethod;
+	private static Method updateKeyValueMethod;
+	private static Method getKeyValueMethod;
+	
+	// Entity methods
+	private static Field entityDataField;
+	
+	/**
+	 * Whether or not this class has already been initialized.
+	 */
+	private static boolean hasInitialized;
+	
+	// The underlying DataWatcher we're modifying
+	protected DataWatcher handle;
+	
+	// Lock
+	private ReadWriteLock readWriteLock;
+	
+	// Map of watchable objects
+	private Map<Integer, Object> watchableObjects;
+	
+	/**
+	 * Initialize a new data watcher.
+	 * @throws FieldAccessException If we're unable to wrap a DataWatcher.
+	 */
+	public WrappedDataWatcher() {
+		// Just create a new watcher
+		this(new DataWatcher());
+	}
+	
+	/**
+	 * Create a wrapper for a given data watcher.
+	 * @param dataWatcher - the data watcher to wrap.
+	 * @throws FieldAccessException If we're unable to wrap a DataWatcher.
+	 */
+	public WrappedDataWatcher(DataWatcher handle) {
+		this.handle = handle;
+		
+		try {
+			initialize();
+		} catch (FieldAccessException e) {
+			throw new RuntimeException("Cannot initialize wrapper.", e);
+		}
+	}
+	
+	/**
+	 * Create a new data watcher from a list of watchable objects.
+	 * @param watchableObjects - list of watchable objects that will be copied.
+	 * @throws FieldAccessException Unable to read watchable objects.
+	 */
+	public WrappedDataWatcher(List<WrappedWatchableObject> watchableObjects) throws FieldAccessException {
+		this();
+		
+		// Fill the underlying map
+		for (WrappedWatchableObject watched : watchableObjects) {
+			setObject(watched.getIndex(), watched.getValue());
+		}
+	}
+	
+	/**
+	 * Retrieves the underlying data watcher.
+	 * @return The underlying data watcher.
+	 */
+	public DataWatcher getHandle() {
+		return handle;
+	}
+	
+	/**
+	 * Retrieve the ID of a given type, if it's allowed to be watched.
+	 * @return The ID, or NULL if it cannot be watched.
+	 * @throws FieldAccessException If we cannot initialize the reflection machinery.
+	 */
+	public static Integer getTypeID(Class<?> clazz) throws FieldAccessException {
+		initialize();
+		
+		return typeMap.get(clazz);
+	}
+	
+	/**
+	 * Retrieve the type of a given ID, if it's allowed to be watched.
+	 * @return The type using a given ID, or NULL if it cannot be watched.
+	 * @throws FieldAccessException If we cannot initialize the reflection machinery.
+	 */
+	public static Class<?> getTypeClass(int id) throws FieldAccessException {
+		initialize();
+		
+		for (Map.Entry<Class<?>, Integer> entry : typeMap.entrySet()) {
+			if (Objects.equal(entry.getValue(), id)) {
+				return entry.getKey();
+			}
+		}
+		
+		// Unknown class type
+		return null;
+	}
+	
+    /**
+     * Get a watched byte.
+     * @param index - index of the watched byte.
+     * @return The watched byte, or NULL if this value doesn't exist.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public Byte getByte(int index) throws FieldAccessException {
+    	return (Byte) getObjectRaw(index);
+    }
+    
+    /**
+     * Get a watched short.
+     * @param index - index of the watched short.
+     * @return The watched short, or NULL if this value doesn't exist.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public Short getShort(int index) throws FieldAccessException {
+    	return (Short) getObjectRaw(index);
+    }
+    
+    /**
+     * Get a watched integer.
+     * @param index - index of the watched integer.
+     * @return The watched integer, or NULL if this value doesn't exist.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public Integer getInteger(int index) throws FieldAccessException {
+    	return (Integer) getObjectRaw(index);
+    }
+    
+    /**
+     * Get a watched float.
+     * @param index - index of the watched float.
+     * @return The watched float, or NULL if this value doesn't exist.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public Float getFloat(int index) throws FieldAccessException {
+    	return (Float) getObjectRaw(index);
+    }
+    
+    /**
+     * Get a watched string.
+     * @param index - index of the watched string.
+     * @return The watched string, or NULL if this value doesn't exist.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public String getString(int index) throws FieldAccessException {
+    	return (String) getObjectRaw(index);
+    }
+    
+    /**
+     * Get a watched string.
+     * @param index - index of the watched string.
+     * @return The watched string, or NULL if this value doesn't exist.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public ItemStack getItemStack(int index) throws FieldAccessException {
+    	return (ItemStack) getObject(index);
+    }
+    
+    /**
+     * Get a watched string.
+     * @param index - index of the watched string.
+     * @return The watched string, or NULL if this value doesn't exist.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public WrappedChunkCoordinate getChunkCoordinate(int index) throws FieldAccessException {
+    	return (WrappedChunkCoordinate) getObject(index);
+    }
+    
+    /**
+     * Retrieve a watchable object by index.
+     * @param index - index of the object to retrieve.
+     * @return The watched object.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public Object getObject(int index) throws FieldAccessException {
+    	Object result = getObjectRaw(index);
+    	
+    	// Handle the special cases too
+    	if (result instanceof net.minecraft.server.ItemStack) {
+    		return BukkitConverters.getItemStackConverter().getSpecific(result);
+    	} else if (result instanceof ChunkCoordinates) {
+    		return new WrappedChunkCoordinate((ChunkCoordinates) result);
+    	} else {
+    		return result;
+    	}
+    }
+    
+    /**
+     * Retrieve a watchable object by index.
+     * @param index - index of the object to retrieve.
+     * @return The watched object.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    private Object getObjectRaw(int index) throws FieldAccessException {
+    	// The get method will take care of concurrency
+    	WatchableObject watchable = getWatchedObject(index);
+
+    	if (watchable != null) {
+    		return new WrappedWatchableObject(watchable).getValue();
+    	} else {
+    		return null;
+    	}
+    }
+    
+    /**
+     * Retrieve every watchable object in this watcher.
+     * @return Every watchable object.
+     * @throws FieldAccessException If reflection failed.
+     */
+	public List<WrappedWatchableObject> getWatchableObjects() throws FieldAccessException {
+    	try {
+    		getReadWriteLock().readLock().lock();
+    		
+    		List<WrappedWatchableObject> result = new ArrayList<WrappedWatchableObject>();
+    		
+    		// Add each watchable object to the list
+    		for (Object watchable : getWatchableObjectMap().values()) {
+    			if (watchable != null) {
+    				result.add(new WrappedWatchableObject((WatchableObject) watchable));
+    			} else {
+    				result.add(null);
+    			}
+    		}
+    		return result;
+    		
+    	} finally {
+    		getReadWriteLock().readLock().unlock();
+    	}
+    }
+
+    /**
+     * Retrieve a copy of every index associated with a watched object.
+     * @return Every watched object index.
+     * @throws FieldAccessException If we're unable to read the underlying object.
+     */
+    public Set<Integer> indexSet() throws FieldAccessException {
+    	try {
+    		getReadWriteLock().readLock().lock();
+    		return new HashSet<Integer>(getWatchableObjectMap().keySet());
+    		
+    	} finally {
+    		getReadWriteLock().readLock().unlock();
+    	}
+    }
+    
+    /**
+     * Retrieve the number of watched objects.
+     * @return Watched object count.
+     * @throws FieldAccessException If we're unable to read the underlying object.
+     */
+    public int size() throws FieldAccessException {
+    	try {
+    		getReadWriteLock().readLock().lock();
+    		return getWatchableObjectMap().size();
+    		
+    	} finally {
+    		getReadWriteLock().readLock().unlock();
+    	}
+    }
+    
+    /**
+     * Set a watched byte.
+     * @param index - index of the watched byte.
+     * @param newValue - the new watched value.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public void setObject(int index, Object newValue) throws FieldAccessException {
+    	setObject(index, newValue, true);
+    }
+    
+    /**
+     * Set a watched byte.
+     * @param index - index of the watched byte.
+     * @param newValue - the new watched value.
+     * @param update - whether or not to refresh every listening clients.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    public void setObject(int index, Object newValue, boolean update) throws FieldAccessException {
+    	// Convert special cases
+    	if (newValue instanceof WrappedChunkCoordinate)
+    		newValue = ((WrappedChunkCoordinate) newValue).getHandle();
+    	if (newValue instanceof ItemStack)
+    		newValue = BukkitConverters.getItemStackConverter().getGeneric(
+    				net.minecraft.server.ItemStack.class, (ItemStack) newValue);
+    	
+    	// Next, set the object
+    	setObjectRaw(index, newValue, update);
+    }
+    
+    /**
+     * Set a watchable object by index.
+     * @param index - index of the object to retrieve.
+     * @param newValue - the new watched value.
+     * @param update - whether or not to refresh every listening clients.
+     * @return The watched object.
+     * @throws FieldAccessException Cannot read underlying field.
+     */
+    private void setObjectRaw(int index, Object newValue, boolean update) throws FieldAccessException {
+    	WatchableObject watchable;
+    	
+    	try {
+    		// Aquire write lock
+    		getReadWriteLock().writeLock().lock();
+    		watchable = getWatchedObject(index);
+	    	
+	    	if (watchable != null) {
+	    		new WrappedWatchableObject(watchable).setValue(newValue, update);
+	    	}
+    	} finally {
+    		getReadWriteLock().writeLock().unlock();
+    	}
+    }
+        
+    private WatchableObject getWatchedObject(int index) throws FieldAccessException {
+    	// We use the get-method first and foremost
+    	if (getKeyValueMethod != null) {
+			try {
+				return (WatchableObject) getKeyValueMethod.invoke(handle, index);
+			} catch (Exception e) {
+				throw new FieldAccessException("Cannot invoke get key method for index " + index, e);
+			}
+    	} else {
+    		try {
+    			getReadWriteLock().readLock().lock();
+    			return (WatchableObject) getWatchableObjectMap().get(index);
+    			
+    		} finally {
+    			getReadWriteLock().readLock().unlock();
+    		}
+    	}
+    }
+    
+    /**
+     * Retrieve the current read write lock.
+     * @return Current read write lock.
+     * @throws FieldAccessException If we're unable to read the underlying field.
+     */
+    protected ReadWriteLock getReadWriteLock() throws FieldAccessException {
+    	try {
+	    	// Cache the read write lock
+	    	if (readWriteLock != null)
+	    		return readWriteLock;
+	    	else if (readWriteLockField != null)
+	    		return readWriteLock = (ReadWriteLock) FieldUtils.readField(readWriteLockField, handle, true);
+	    	else
+	    		return readWriteLock = new ReentrantReadWriteLock();
+    	} catch (IllegalAccessException e) {
+    		throw new FieldAccessException("Unable to read lock field.", e);
+    	}
+    }
+    
+    /**
+	 * Retrieve the underlying map of key values that stores watchable objects.
+	 * @return A map of watchable objects.
+	 * @throws FieldAccessException If we don't have permission to perform reflection.
+	 */
+	@SuppressWarnings("unchecked")
+	protected Map<Integer, Object> getWatchableObjectMap() throws FieldAccessException {
+		if (watchableObjects == null) {
+			try {
+				watchableObjects = (Map<Integer, Object>) FieldUtils.readField(valueMapField, handle, true);
+			} catch (IllegalAccessException e) {
+				throw new FieldAccessException("Cannot read watchable object field.", e);
+			}
+		}
+		return watchableObjects;
+	}
+	
+	/**
+	 * Retrieve the data watcher associated with an entity.
+	 * @param entity - the entity to read from.
+	 * @return Associated data watcher.
+	 * @throws FieldAccessException Reflection failed.
+	 */
+	public static WrappedDataWatcher getEntityWatcher(Entity entity) throws FieldAccessException {
+		if (entityDataField == null)
+			entityDataField = FuzzyReflection.fromClass(net.minecraft.server.Entity.class, true).
+				getFieldByType("datawatcher", DataWatcher.class);
+
+		BukkitUnwrapper unwrapper = new BukkitUnwrapper();
+		
+		try {
+			Object nsmWatcher = FieldUtils.readField(entityDataField, unwrapper.unwrapItem(entity), true);
+			
+			if (nsmWatcher != null) 
+				return new WrappedDataWatcher((DataWatcher) nsmWatcher);
+			else 
+				return null;
+			
+		} catch (IllegalAccessException e) {
+			throw new FieldAccessException("Cannot access DataWatcher field.", e);
+		}
+	}
+	
+	/**
+	 * Invoked when a data watcher is first used.
+	 */
+	@SuppressWarnings("unchecked")
+	private static void initialize() throws FieldAccessException {
+		// This method should only be run once, even if an exception is thrown
+		if (!hasInitialized)
+			hasInitialized = true;
+		else
+			return;
+		
+		FuzzyReflection fuzzy = FuzzyReflection.fromClass(DataWatcher.class, true);
+		
+		for (Field lookup : fuzzy.getFieldListByType(Map.class)) {
+			if (Modifier.isStatic(lookup.getModifiers())) {
+				// This must be the type map
+				try {
+					typeMap = (Map<Class<?>, Integer>) FieldUtils.readStaticField(lookup, true);
+				} catch (IllegalAccessException e) {
+					throw new FieldAccessException("Cannot access type map field.", e);
+				}
+				
+			} else {
+				// If not, then we're probably dealing with the value map
+				valueMapField = lookup;
+			}
+		}
+		
+		try {
+			readWriteLockField = fuzzy.getFieldByType("readWriteLock", ReadWriteLock.class);
+		} catch (IllegalArgumentException e) {
+			// It's not a big deal
+		}
+		
+		initializeMethods(fuzzy);
+	}
+	
+	private static void initializeMethods(FuzzyReflection fuzzy) {
+		List<Method> candidates = fuzzy.getMethodListByParameters(Void.TYPE, 
+				  					new Class<?>[] { int.class, Object.class});
+		
+		for (Method method : candidates) {
+			
+			if (!method.getName().startsWith("watch")) {
+				createKeyValueMethod = method;
+			} else {
+				updateKeyValueMethod = method;
+			}
+		}
+		
+		// Did we succeed?
+		if (updateKeyValueMethod == null || createKeyValueMethod == null) {
+			// Go by index instead
+			if (candidates.size() > 1) {
+				createKeyValueMethod = candidates.get(0);
+				updateKeyValueMethod = candidates.get(1);
+			} else {
+				throw new IllegalStateException("Unable to find create and update watchable object. Update ProtocolLib.");
+			}
+		}
+		
+		// Load the get-method
+		try {
+			getKeyValueMethod = fuzzy.getMethodByParameters(
+					"getWatchableObject", ".*WatchableObject", new String[] { int.class.getName() });
+			getKeyValueMethod.setAccessible(true);
+		} catch (IllegalArgumentException e) {
+			// Use fallback method
+		}
+	}
+}

ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/WrappedWatchableObject.java

@@ -0,0 +1,160 @@
+package com.comphenix.protocol.wrappers;
+
+import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.StructureModifier;
+
+import net.minecraft.server.WatchableObject;
+
+/**
+ * Represents a watchable object.
+ * 
+ * @author Kristian
+ */
+public class WrappedWatchableObject {
+
+	// Whether or not the reflection machinery has been initialized
+	private static boolean hasInitialized;
+	
+	// The field containing the value itself
+	private static StructureModifier<Object> baseModifier;
+	
+	protected WatchableObject handle;
+	protected StructureModifier<Object> modifier;
+	
+	// Type of the stored value
+	private Class<?> typeClass;
+	
+	public WrappedWatchableObject(WatchableObject handle) {
+		initialize();
+		this.handle = handle;
+		this.modifier = baseModifier.withTarget(handle);
+	}
+	
+	/**
+	 * Retrieves the underlying watchable object.
+	 * @return The underlying watchable object.
+	 */
+	public WatchableObject getHandle() {
+		return handle;
+	}
+	
+	/**
+	 * Initialize reflection machinery.
+	 */
+	private static void initialize() {
+		if (!hasInitialized) {
+			hasInitialized = true;
+			baseModifier = new StructureModifier<Object>(WatchableObject.class, null, false);
+		}
+	}
+	
+	/**
+	 * Retrieve the correct super type of the current value.
+	 * @return Super type.
+	 * @throws FieldAccessException Unable to read values.
+	 */
+	public Class<?> getType() throws FieldAccessException {
+		if (typeClass == null) {
+			typeClass = WrappedDataWatcher.getTypeClass(getTypeID());
+			
+			if (typeClass == null) {
+				throw new IllegalStateException("Unrecognized data type: " + getTypeID());
+			}
+		}
+		
+		return typeClass;
+	}
+	
+	/**
+	 * Retrieve the index of this watchable object. This is used to identify a value.
+	 * @return Object index.
+	 * @throws FieldAccessException Reflection failed.
+	 */
+	public int getIndex() throws FieldAccessException {
+		return modifier.<Integer>withType(int.class).read(1);
+	}
+	
+	/**
+	 * Set the the index of this watchable object.
+	 * @param index - the new object index.
+	 * @throws FieldAccessException Reflection failed.
+	 */
+	public void setIndex(int index) throws FieldAccessException {
+		modifier.<Integer>withType(int.class).write(1, index);
+	}
+	
+	/**
+	 * Retrieve the type ID of a watchable object.
+	 * @return Type ID that identifies the type of the value.
+	 * @throws FieldAccessException Reflection failed.
+	 */
+	public int getTypeID() throws FieldAccessException {
+		return modifier.<Integer>withType(int.class).read(0);
+	}
+	
+	/**
+	 * Set the type ID of a watchable object.
+	 * @param id - the new ID.
+	 * @throws FieldAccessException Reflection failed.
+	 */
+	public void setTypeID(int id) throws FieldAccessException {
+		modifier.<Integer>withType(int.class).write(0, id);
+	}
+	
+	/**
+	 * Update the value field.
+	 * @param newValue - new value.
+	 * @throws FieldAccessException Unable to use reflection.
+	 */
+	public void setValue(Object newValue) throws FieldAccessException {
+		setValue(newValue, true);
+	}
+	
+	/**
+	 * Update the value field.
+	 * @param newValue - new value.
+	 * @param updateClient - whether or not to update listening clients.
+	 * @throws FieldAccessException Unable to use reflection.
+	 */
+	public void setValue(Object newValue, boolean updateClient) throws FieldAccessException {
+		// Verify a few quick things
+		if (newValue == null)
+			throw new IllegalArgumentException("Cannot watch a NULL value.");
+		if (!getType().isAssignableFrom(newValue.getClass()))
+			throw new IllegalArgumentException("Object " + newValue +  " must be of type " + getType().getName());
+		
+		// See if we should update the client to
+		if (updateClient)
+			setDirtyState(true);
+		
+		// Use the modifier to set the value
+		modifier.withType(Object.class).write(0, newValue);
+	}
+	
+	/**
+	 * Read the value field.
+	 * @return The watched value.
+	 * @throws FieldAccessException Unable to use reflection. 
+	 */
+	public Object getValue() throws FieldAccessException {
+		return modifier.withType(Object.class).read(0);
+	}
+	
+	/**
+	 * Set whether or not the value must be synchronized with the client.
+	 * @param dirty - TRUE if the value should be synchronized, FALSE otherwise.
+	 * @throws FieldAccessException Unable to use reflection.
+	 */
+	public void setDirtyState(boolean dirty) throws FieldAccessException {
+		modifier.<Boolean>withType(boolean.class).write(0, dirty);
+	}
+	
+	/**
+	 * Retrieve whether or not the value must be synchronized with the client.
+	 * @return TRUE if the value should be synchronized, FALSE otherwise.
+	 * @throws FieldAccessException Unable to use reflection.
+	 */
+	public boolean getDirtyState() throws FieldAccessException {
+		return modifier.<Boolean>withType(boolean.class).read(0);
+	}
+}

ProtocolLib/src/main/resources/plugin.yml

@@ -1,5 +1,5 @@
 name: ProtocolLib
-version: 1.5.1
+version: 1.6.0
 description: Provides read/write access to the Minecraft protocol.
 author: Comphenix
 website: http://www.comphenix.net/ProtocolLib
@@ -11,12 +11,12 @@ commands:
   protocol:
     description: Performs administrative tasks regarding ProtocolLib.
     usage: /<command> config|check|update
-    permission: experiencemod.admin
+    permission: protocol.admin
     permission-message: You don't have <permission>
   packet:
     description: Add or remove a simple packet listener.
     usage: /<command> add|remove|names client|server [ID start]-[ID stop] [detailed]
-    permission: experiencemod.admin
+    permission: protocol.admin
     permission-message: You don't have <permission>
 
 permissions: