Improved Json record support (Gson 2.10 natively supports it) + Added ItemStack Json support

- Extract RecordTypeAdapter to its own file + only use it if Gson library does not support it (it does since 2.10, but we are unsure of which version is actually used in paper/bungee/other)
- new ItemStackAdapter to support Json (de)serializing of Bukkit ItemStack.

pandalib-core/src/main/java/fr/pandacube/lib/core/json/Json.java

@@ -1,23 +1,15 @@
 package fr.pandacube.lib.core.json;
 
-import java.io.IOException;
-import java.lang.reflect.Constructor;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.RecordComponent;
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.function.Function;
 
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.TypeAdapter;
 import com.google.gson.TypeAdapterFactory;
+import com.google.gson.internal.bind.ReflectiveTypeAdapterFactory;
 import com.google.gson.reflect.TypeToken;
-import com.google.gson.stream.JsonReader;
-import com.google.gson.stream.JsonToken;
-import com.google.gson.stream.JsonWriter;
 
 /**
  * Provides pre-instanciated {@link Gson} instances, all with support for Java records and additionnal
@@ -98,81 +90,19 @@ public class Json {
 
 
 
-
+	private static boolean hasGsonNativeRecordSupport() {
+		for (Class<?> innerClasses : ReflectiveTypeAdapterFactory.class.getDeclaredClasses()) {
+			if (innerClasses.getSimpleName().equals("RecordAdapter"))
+				return true;
+		}
+		return false;
+	}
 
 
 
 	static {
-		registerTypeAdapterFactory(new RecordAdapterFactory());
+		if (!hasGsonNativeRecordSupport())
+			registerTypeAdapterFactory(RecordTypeAdapter.FACTORY);
 	}
 
-	// from https://github.com/google/gson/issues/1794#issuecomment-812964421
-	private static class RecordAdapterFactory implements TypeAdapterFactory {
-		@Override
-		public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
-			@SuppressWarnings("unchecked")
-			Class<T> clazz = (Class<T>) type.getRawType();
-			if (!clazz.isRecord() || clazz == Record.class) {
-				return null;
-			}
-			return new RecordTypeAdapter<>(gson, this, type);
-		}
-	}
-
-	private static class RecordTypeAdapter<T> extends TypeAdapter<T> {
-		private final Gson gson;
-		private final TypeAdapterFactory factory;
-		private final TypeToken<T> type;
-
-		public RecordTypeAdapter(Gson gson, TypeAdapterFactory factory, TypeToken<T> type) {
-			this.gson = gson;
-			this.factory = factory;
-			this.type = type;
-		}
-
-		@Override
-		public void write(JsonWriter out, T value) throws IOException {
-			gson.getDelegateAdapter(factory, type).write(out, value);
-		}
-
-		@Override
-		public T read(JsonReader reader) throws IOException {
-			if (reader.peek() == JsonToken.NULL) {
-				reader.nextNull();
-				return null;
-			} else {
-				@SuppressWarnings("unchecked")
-				Class<T> clazz = (Class<T>) type.getRawType();
-
-				RecordComponent[] recordComponents = clazz.getRecordComponents();
-				Map<String, TypeToken<?>> typeMap = new HashMap<>();
-				for (RecordComponent recordComponent : recordComponents) {
-					typeMap.put(recordComponent.getName(), TypeToken.get(recordComponent.getGenericType()));
-				}
-				var argsMap = new HashMap<String, Object>();
-				reader.beginObject();
-				while (reader.hasNext()) {
-					String name = reader.nextName();
-					argsMap.put(name, gson.getAdapter(typeMap.get(name)).read(reader));
-				}
-				reader.endObject();
-
-				var argTypes = new Class<?>[recordComponents.length];
-				var args = new Object[recordComponents.length];
-				for (int i = 0; i < recordComponents.length; i++) {
-					argTypes[i] = recordComponents[i].getType();
-					args[i] = argsMap.get(recordComponents[i].getName());
-				}
-				Constructor<T> constructor;
-				try {
-					constructor = clazz.getDeclaredConstructor(argTypes);
-					constructor.setAccessible(true);
-					return constructor.newInstance(args);
-				} catch (NoSuchMethodException | InstantiationException | SecurityException | IllegalAccessException
-						| IllegalArgumentException | InvocationTargetException e) {
-					throw new RuntimeException(e);
-				}
-			}
-		}
-	}
 }

pandalib-core/src/main/java/fr/pandacube/lib/core/json/RecordTypeAdapter.java

@@ -0,0 +1,88 @@
+package fr.pandacube.lib.core.json;
+
+import com.google.gson.Gson;
+import com.google.gson.TypeAdapter;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.JsonWriter;
+
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.RecordComponent;
+import java.util.HashMap;
+import java.util.Map;
+
+// from https://github.com/google/gson/issues/1794#issuecomment-812964421
+/* package */ class RecordTypeAdapter<T> extends TypeAdapter<T> {
+
+    public static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
+        @Override
+        public <TT> TypeAdapter<TT> create(Gson gson, TypeToken<TT> type) {
+            @SuppressWarnings("unchecked")
+            Class<TT> clazz = (Class<TT>) type.getRawType();
+            if (!clazz.isRecord() || clazz == Record.class) {
+                return null;
+            }
+            return new RecordTypeAdapter<>(gson, this, type);
+        }
+    };
+
+
+    private final Gson gson;
+    private final TypeAdapterFactory factory;
+    private final TypeToken<T> type;
+
+    public RecordTypeAdapter(Gson gson, TypeAdapterFactory factory, TypeToken<T> type) {
+        this.gson = gson;
+        this.factory = factory;
+        this.type = type;
+    }
+
+    @Override
+    public void write(JsonWriter out, T value) throws IOException {
+        gson.getDelegateAdapter(factory, type).write(out, value);
+    }
+
+    @Override
+    public T read(JsonReader reader) throws IOException {
+        if (reader.peek() == JsonToken.NULL) {
+            reader.nextNull();
+            return null;
+        } else {
+            @SuppressWarnings("unchecked")
+            Class<T> clazz = (Class<T>) type.getRawType();
+
+            RecordComponent[] recordComponents = clazz.getRecordComponents();
+            Map<String, TypeToken<?>> typeMap = new HashMap<>();
+            for (RecordComponent recordComponent : recordComponents) {
+                typeMap.put(recordComponent.getName(), TypeToken.get(recordComponent.getGenericType()));
+            }
+            var argsMap = new HashMap<String, Object>();
+            reader.beginObject();
+            while (reader.hasNext()) {
+                String name = reader.nextName();
+                argsMap.put(name, gson.getAdapter(typeMap.get(name)).read(reader));
+            }
+            reader.endObject();
+
+            var argTypes = new Class<?>[recordComponents.length];
+            var args = new Object[recordComponents.length];
+            for (int i = 0; i < recordComponents.length; i++) {
+                argTypes[i] = recordComponents[i].getType();
+                args[i] = argsMap.get(recordComponents[i].getName());
+            }
+            Constructor<T> constructor;
+            try {
+                constructor = clazz.getDeclaredConstructor(argTypes);
+                constructor.setAccessible(true);
+                return constructor.newInstance(args);
+            } catch (NoSuchMethodException | InstantiationException | SecurityException | IllegalAccessException
+                     | IllegalArgumentException | InvocationTargetException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+}

pandalib-paper/src/main/java/fr/pandacube/lib/paper/PandaLibPaper.java

@@ -1,5 +1,6 @@
 package fr.pandacube.lib.paper;
 
+import fr.pandacube.lib.paper.json.PaperJson;
 import fr.pandacube.lib.paper.modules.PerformanceAnalysisManager;
 import org.bukkit.plugin.Plugin;
 
@@ -9,6 +10,7 @@ public class PandaLibPaper {
 	
 	public static void onLoad(Plugin plugin) {
 		PandaLibPaper.plugin = plugin;
+		PaperJson.init();
 	}
 
 	public static void onEnable() {

pandalib-paper/src/main/java/fr/pandacube/lib/paper/json/ItemStackAdapter.java

@@ -0,0 +1,34 @@
+package fr.pandacube.lib.paper.json;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.internal.bind.TreeTypeAdapter;
+import com.google.gson.reflect.TypeToken;
+import org.bukkit.inventory.ItemStack;
+
+import java.lang.reflect.Type;
+import java.util.Map;
+
+/* package */ class ItemStackAdapter implements JsonSerializer<ItemStack>, JsonDeserializer<ItemStack> {
+
+    private static final TypeToken<ItemStack> ITEMSTACK_TYPE = TypeToken.get(ItemStack.class);
+    public static final TypeAdapterFactory FACTORY = TreeTypeAdapter.newFactoryWithMatchRawType(ITEMSTACK_TYPE, new ItemStackAdapter());
+
+    private static final TypeToken<Map<String, Object>> MAP_STR_OBJ_TYPE = new TypeToken<>() { };
+
+
+    @Override
+    public ItemStack deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
+        return ItemStack.deserialize(context.deserialize(json, MAP_STR_OBJ_TYPE.getType()));
+    }
+
+    @Override
+    public JsonElement serialize(ItemStack src, Type typeOfSrc, JsonSerializationContext context) {
+        return context.serialize(src.serialize(), MAP_STR_OBJ_TYPE.getType());
+    }
+}

pandalib-paper/src/main/java/fr/pandacube/lib/paper/json/PaperJson.java

@@ -0,0 +1,16 @@
+package fr.pandacube.lib.paper.json;
+
+import fr.pandacube.lib.core.json.Json;
+
+/**
+ * Utility class to register Json adapters related to paper API classes.
+ */
+public class PaperJson {
+
+    /**
+     * Registers Json adapters related to paper API classes.
+     */
+    public static void init() {
+        Json.registerTypeAdapterFactory(ItemStackAdapter.FACTORY);
+    }
+}

pandalib-util/src/main/java/fr/pandacube/lib/util/BiMap.java

@@ -13,6 +13,7 @@ import java.util.function.Supplier;
  * A bi-direction map storing in a synchronized way a {@code forwardMap} that store the key to value mapping, and a
  * {@code backwardMap} that store the value to key mapping.
  * All the keys and value are always unique in this bi-directional map.
+ * This class is fully thread safe.
  * @param <K> the type of the "key"
  * @param <V> the type of the "value"
  */