Make compatible with older netty

common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/data/MappingData.java

@@ -16,13 +16,13 @@ import java.util.HashMap;
 import java.util.Map;
 
 public class MappingData {
-    public static IntObjectMap<Integer> oldToNewBlocks = new IntObjectHashMap<>();
     public static BiMap<Integer, Integer> oldToNewItems = HashBiMap.create();
     public static Map<String, Integer[]> blockTags = new HashMap<>();
     public static Map<String, Integer[]> itemTags = new HashMap<>();
     public static Map<String, Integer[]> fluidTags = new HashMap<>();
     public static BiMap<Short, String> oldEnchantmentsIds = HashBiMap.create();
     public static Map<Integer, Integer> oldToNewSounds = new HashMap<>();
+    public static BlockMappings blockMappings;
 
     public static void init() {
         JsonObject mapping1_12 = loadData("mapping-1.12.json");
@@ -30,7 +30,12 @@ public class MappingData {
 
         // TODO: Remove how verbose this is
         System.out.println("Loading block mapping...");
-        mapIdentifiers(oldToNewBlocks, mapping1_12.getAsJsonObject("blocks"), mapping1_13.getAsJsonObject("blocks"));
+        try {
+            blockMappings = new BMNettyCollections();
+        } catch (NoClassDefFoundError e) {
+            blockMappings = new BMJDKCollections();
+        }
+        blockMappings.init(mapping1_12, mapping1_13);
         System.out.println("Loading item mapping...");
         mapIdentifiers(oldToNewItems, mapping1_12.getAsJsonObject("items"), mapping1_13.getAsJsonObject("items"));
         System.out.println("Loading new tags...");
@@ -54,17 +59,6 @@ public class MappingData {
         }
     }
 
-    private static void mapIdentifiers(IntObjectMap<Integer> output, JsonObject oldIdentifiers, JsonObject newIdentifiers) {
-        for (Map.Entry<String, JsonElement> entry : oldIdentifiers.entrySet()) {
-            Map.Entry<String, JsonElement> value = findValue(newIdentifiers, entry.getValue().getAsString());
-            if (value == null) {
-                System.out.println("No key for " + entry.getValue() + " :( ");
-                continue;
-            }
-            output.put(Integer.parseInt(entry.getKey()), Integer.parseInt(value.getKey()));
-        }
-    }
-
     private static Map.Entry<String, JsonElement> findValue(JsonObject object, String needle) {
         for (Map.Entry<String, JsonElement> entry : object.entrySet()) {
             String value = entry.getValue().getAsString();
@@ -128,4 +122,48 @@ public class MappingData {
             }
         }
     }
+
+    public interface BlockMappings {
+        void init(JsonObject mapping1_12, JsonObject mapping1_13);
+        Integer getNewBlock(int old);
+    }
+
+    private static class BMJDKCollections implements BlockMappings {
+        private Map<Integer, Integer> oldToNew = new HashMap<>();
+
+        @Override
+        public void init(JsonObject mapping1_12, JsonObject mapping1_13) {
+            mapIdentifiers(oldToNew, mapping1_12.getAsJsonObject("blocks"), mapping1_13.getAsJsonObject("blocks"));
+        }
+
+        @Override
+        public Integer getNewBlock(int old) {
+            return oldToNew.get(old);
+        }
+    }
+
+    private static class BMNettyCollections implements BlockMappings {
+        private IntObjectMap<Integer> oldToNew = new IntObjectHashMap<>();
+
+        @Override
+        public void init(JsonObject mapping1_12, JsonObject mapping1_13) {
+            mapIdentifiers(oldToNew, mapping1_12.getAsJsonObject("blocks"), mapping1_13.getAsJsonObject("blocks"));
+        }
+
+        @Override
+        public Integer getNewBlock(int old) {
+            return oldToNew.get(old);
+        }
+
+        private static void mapIdentifiers(IntObjectMap<Integer> output, JsonObject oldIdentifiers, JsonObject newIdentifiers) {
+            for (Map.Entry<String, JsonElement> entry : oldIdentifiers.entrySet()) {
+                Map.Entry<String, JsonElement> value = findValue(newIdentifiers, entry.getValue().getAsString());
+                if (value == null) {
+                    System.out.println("No key for " + entry.getValue() + " :( ");
+                    continue;
+                }
+                output.put(Integer.parseInt(entry.getKey()), Integer.parseInt(value.getKey()));
+            }
+        }
+    }
 }

common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/packets/WorldPackets.java

@@ -256,11 +256,11 @@ public class WorldPackets {
     }
 
     public static int toNewId(int oldId) {
-        Integer newId = MappingData.oldToNewBlocks.get(oldId);
+        Integer newId = MappingData.blockMappings.getNewBlock(oldId);
         if (newId != null) {
             return newId;
         }
-        newId = MappingData.oldToNewBlocks.get(oldId & ~0xF); // Remove data
+        newId = MappingData.blockMappings.getNewBlock(oldId & ~0xF); // Remove data
         if (newId != null) {
             System.out.println("Missing block " + oldId);
             return newId;

pom.xml

@@ -95,10 +95,12 @@
         </dependency>
 
         <!-- Netty (Network Library) -->
+        <!-- You should make this work with 4.0.20.Final -->
+        <!-- Using 4.0.23.Final to use Netty Collections -->
         <dependency>
             <groupId>io.netty</groupId>
             <artifactId>netty-all</artifactId>
-            <version>4.0.23.Final</version> <!-- Let's break 1.8 -->
+            <version>4.0.23.Final</version>
             <scope>provided</scope>
             <optional>true</optional>
         </dependency>