Added a generic GSON Type Adapter for ConfigurationSerializabale objects

Bukkit has built-in serialization that can be used. Kept legacy
serialization for backwards compatibility and compactness.

src/main/java/world/bentobox/bentobox/database/json/AbstractJSONDatabaseHandler.java

@@ -1,24 +1,11 @@
 package world.bentobox.bentobox.database.json;
 
-import org.bukkit.Location;
-import org.bukkit.World;
-import org.bukkit.inventory.ItemStack;
-import org.bukkit.potion.PotionEffectType;
-import org.bukkit.util.BoundingBox;
-
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 
 import world.bentobox.bentobox.BentoBox;
-import world.bentobox.bentobox.api.flags.Flag;
 import world.bentobox.bentobox.database.AbstractDatabaseHandler;
 import world.bentobox.bentobox.database.DatabaseConnector;
-import world.bentobox.bentobox.database.json.adapters.BoundingBoxTypeAdapter;
-import world.bentobox.bentobox.database.json.adapters.FlagTypeAdapter;
-import world.bentobox.bentobox.database.json.adapters.ItemStackTypeAdapter;
-import world.bentobox.bentobox.database.json.adapters.LocationTypeAdapter;
-import world.bentobox.bentobox.database.json.adapters.PotionEffectTypeAdapter;
-import world.bentobox.bentobox.database.json.adapters.WorldTypeAdapter;
 
 /**
  * Abstract class that handles insert/select-operations into/from a database.
@@ -48,13 +35,8 @@ public abstract class AbstractJSONDatabaseHandler<T> extends AbstractDatabaseHan
         // excludeFieldsWithoutExposeAnnotation - this means that every field to be stored should use @Expose
         // enableComplexMapKeySerialization - forces GSON to use TypeAdapters even for Map keys
         GsonBuilder builder = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().enableComplexMapKeySerialization().setPrettyPrinting();
-        // Register adapters
-        builder.registerTypeAdapter(Location.class, new LocationTypeAdapter()) ;
-        builder.registerTypeAdapter(World.class, new WorldTypeAdapter());
-        builder.registerTypeAdapter(Flag.class, new FlagTypeAdapter(plugin));
-        builder.registerTypeAdapter(PotionEffectType.class, new PotionEffectTypeAdapter());
-        builder.registerTypeAdapter(ItemStack.class, new ItemStackTypeAdapter());
-        builder.registerTypeAdapter(BoundingBox.class, new BoundingBoxTypeAdapter());
+        // Register adapter factory
+        builder.registerTypeAdapterFactory(new BentoboxTypeAdapterFactory(plugin));
         // Keep null in the database
         builder.serializeNulls();
         // Allow characters like < or > without escaping them

src/main/java/world/bentobox/bentobox/database/json/BentoboxTypeAdapterFactory.java

@@ -0,0 +1,71 @@
+/**
+ *
+ */
+package world.bentobox.bentobox.database.json;
+
+import java.util.Map;
+
+import org.bukkit.Location;
+import org.bukkit.World;
+import org.bukkit.configuration.serialization.ConfigurationSerializable;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.potion.PotionEffectType;
+
+import com.google.gson.Gson;
+import com.google.gson.TypeAdapter;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.reflect.TypeToken;
+
+import world.bentobox.bentobox.BentoBox;
+import world.bentobox.bentobox.api.flags.Flag;
+import world.bentobox.bentobox.database.json.adapters.BukkitObjectTypeAdapter;
+import world.bentobox.bentobox.database.json.adapters.FlagTypeAdapter;
+import world.bentobox.bentobox.database.json.adapters.ItemStackTypeAdapter;
+import world.bentobox.bentobox.database.json.adapters.LocationTypeAdapter;
+import world.bentobox.bentobox.database.json.adapters.PotionEffectTypeAdapter;
+import world.bentobox.bentobox.database.json.adapters.WorldTypeAdapter;
+
+/**
+ * Allocates type adapters based on class type.
+ *
+ * @author tastybento
+ *
+ */
+public class BentoboxTypeAdapterFactory implements TypeAdapterFactory {
+
+    BentoBox plugin;
+
+    /**
+     * @param plugin
+     */
+    public BentoboxTypeAdapterFactory(BentoBox plugin) {
+        this.plugin = plugin;
+    }
+
+    /* (non-Javadoc)
+     * @see com.google.gson.TypeAdapterFactory#create(com.google.gson.Gson, com.google.gson.reflect.TypeToken)
+     */
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+        Class<?> rawType = type.getRawType();
+        if (Location.class.isAssignableFrom(rawType)) {
+            // Use our current location adapter for backward compatibility
+            return (TypeAdapter<T>) new LocationTypeAdapter();
+        } else if (ItemStack.class.isAssignableFrom(rawType)) {
+            // Use our current location adapter for backward compatibility
+            return (TypeAdapter<T>) new ItemStackTypeAdapter();
+        } else if (Flag.class.isAssignableFrom(rawType)) {
+            return (TypeAdapter<T>) new FlagTypeAdapter(plugin);
+        } else if (PotionEffectType.class.isAssignableFrom(rawType)) {
+            return (TypeAdapter<T>) new PotionEffectTypeAdapter();
+        } else if (World.class.isAssignableFrom(rawType)) {
+            return (TypeAdapter<T>) new WorldTypeAdapter();
+        } else if (ConfigurationSerializable.class.isAssignableFrom(rawType)) {
+            // This covers a lot of Bukkit objects
+            return (TypeAdapter<T>) new BukkitObjectTypeAdapter(gson.getAdapter(Map.class));
+        }
+        return null;
+    }
+
+}

src/main/java/world/bentobox/bentobox/database/json/adapters/BoundingBoxTypeAdapter.java

@@ -1,46 +0,0 @@
-package world.bentobox.bentobox.database.json.adapters;
-
-import java.io.IOException;
-
-import org.bukkit.util.BoundingBox;
-
-import com.google.gson.TypeAdapter;
-import com.google.gson.stream.JsonReader;
-import com.google.gson.stream.JsonToken;
-import com.google.gson.stream.JsonWriter;
-
-public class BoundingBoxTypeAdapter extends TypeAdapter<BoundingBox> {
-
-    @Override
-    public void write(JsonWriter out, BoundingBox box) throws IOException {
-        if (box == null) {
-            out.nullValue();
-            return;
-        }
-        out.beginArray();
-        out.value(box.getMinX());
-        out.value(box.getMinY());
-        out.value(box.getMinZ());
-        out.value(box.getMaxX());
-        out.value(box.getMaxY());
-        out.value(box.getMaxZ());
-        out.endArray();
-    }
-
-    @Override
-    public BoundingBox read(JsonReader in) throws IOException {
-        if (in.peek() == JsonToken.NULL) {
-            in.nextNull();
-            return null;
-        }
-        in.beginArray();
-        double minX = in.nextDouble();
-        double minY = in.nextDouble();
-        double minZ = in.nextDouble();
-        double maxX = in.nextDouble();
-        double maxY = in.nextDouble();
-        double maxZ = in.nextDouble();
-        in.endArray();
-        return new BoundingBox(minX, minY, minZ, maxX, maxY, maxZ);
-    }
-}

src/main/java/world/bentobox/bentobox/database/json/adapters/BukkitObjectTypeAdapter.java

@@ -0,0 +1,73 @@
+package world.bentobox.bentobox.database.json.adapters;
+
+import static org.bukkit.configuration.serialization.ConfigurationSerialization.SERIALIZED_TYPE_KEY;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.bukkit.configuration.serialization.ConfigurationSerializable;
+import org.bukkit.configuration.serialization.ConfigurationSerialization;
+
+import com.google.gson.TypeAdapter;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+
+/**
+ * Handles {@link ConfigurationSerializable} types
+ * @author tastybento
+ * @since 1.5.0
+ */
+
+public class BukkitObjectTypeAdapter extends TypeAdapter<ConfigurationSerializable> {
+
+    @SuppressWarnings("rawtypes")
+    private final TypeAdapter<Map> map;
+
+    @SuppressWarnings("rawtypes")
+    public BukkitObjectTypeAdapter(TypeAdapter<Map> mapAdapter) {
+        this.map = mapAdapter;
+    }
+
+    public static Map<String, Object> serializeObject(ConfigurationSerializable serializable) {
+        Map<String, Object> serialized = new HashMap<>();
+        serialized.putAll(serializable.serialize());
+        serialized.entrySet().stream()
+        .filter(e -> e.getValue() instanceof ConfigurationSerializable)
+        .forEach(e -> serialized.put(e.getKey(), serializeObject((ConfigurationSerializable) e.getValue())));
+        serialized.put(SERIALIZED_TYPE_KEY, ConfigurationSerialization.getAlias(serializable.getClass()));
+        return serialized;
+    }
+
+    @SuppressWarnings("unchecked")
+    public ConfigurationSerializable deserializeObject(Map<String, Object> map) {
+        if (map == null) {
+            return null;
+        }
+        // Iteratively expand maps until the Bukkit ConfigurationSerialization can deserialize the base object
+        map.forEach((k,v) -> {
+            if (v instanceof Map) {
+                Map<String, Object> nestedMap = (Map<String, Object>)v;
+                if (nestedMap.containsKey(SERIALIZED_TYPE_KEY)) {
+                    map.put(k, deserializeObject(nestedMap));
+                }
+            }
+        });
+
+        return ConfigurationSerialization.deserializeObject(map);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public ConfigurationSerializable read(JsonReader in) throws IOException {
+        return deserializeObject(map.read(in));
+    }
+
+    @Override
+    public void write(JsonWriter out, ConfigurationSerializable value) throws IOException {
+        if (value == null) {
+            out.nullValue();
+        }
+        map.write(out, serializeObject(value));
+    }
+}