Added JSON serializer post-load and pre-save hooks.

Author: code-disaster

src/main/java/com/badlogic/gdx/json/AnnotatedJson.java

@@ -5,7 +5,7 @@
 import com.badlogic.gdx.utils.Json;
 import com.badlogic.gdx.utils.JsonWriter;
 
-import java.io.IOException;
+import java.io.*;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
 
@@ -15,24 +15,32 @@
  */
 public class AnnotatedJson {
 
-	public static <T> T read(FileHandle path, Class<T> clazz, Consumer<Json> setupJson) throws IOException {
+	public static <T> Json newReader(Class<T> clazz, Consumer<Json> setupJson) {
 
 		Json json = new Json();
-
 		json.setSerializer(clazz, new AnnotatedJsonSerializer<>(json, clazz));
 
 		if (setupJson != null) {
 			setupJson.accept(json);
 		}
 
+		return json;
+	}
+
+	public static <T> T read(FileHandle path, Class<T> clazz, Consumer<Json> setupJson) throws IOException {
+		Json json = newReader(clazz, setupJson);
+		return read(path, clazz, json);
+	}
+
+	public static <T> T read(FileHandle path, Class<T> clazz, Json json) throws IOException {
 		try {
 			return json.fromJson(clazz, path);
 		} catch (RuntimeException e) {
 			throw new IOException(e);
 		}
 	}
 
-	public static <T> void write(FileHandle path, T object, Class<T> clazz, Consumer<Json> setupJson) {
+	public static <T> Json newWriter(Class<T> clazz, Consumer<Json> setupJson) {
 
 		Json json = new Json(JsonWriter.OutputType.json);
 		json.setSerializer(clazz, new AnnotatedJsonSerializer<>(json, clazz));
@@ -41,10 +49,25 @@ public static <T> void write(FileHandle path, T object, Class<T> clazz, Consumer
 			setupJson.accept(json);
 		}
 
+		return json;
+	}
+
+	public static <T> void write(FileHandle path, T object, Class<T> clazz, Consumer<Json> setupJson) throws IOException {
+		Json json = newWriter(clazz, setupJson);
+		write(path, object, json);
+	}
+
+	public static <T> void write(FileHandle path, T object, Json json) throws IOException {
+
 		String output = json.toJson(object);
 		String prettyOutput = json.prettyPrint(output);
 
-		path.writeString(prettyOutput, false, "UTF-8");
+		try (FileOutputStream fos = new FileOutputStream(path.file(), false)) {
+			try (Writer writer = new OutputStreamWriter(fos, "UTF-8")) {
+				writer.write(prettyOutput);
+				writer.flush();
+			}
+		}
 	}
 
 	/**

src/main/java/com/badlogic/gdx/json/AnnotatedJsonObject.java

@@ -0,0 +1,20 @@
+package com.badlogic.gdx.json;
+
+/**
+ * Optional interface to customize JSON serialization. Classes annotated with
+ * {@link com.badlogic.gdx.json.annotations.JsonSerializable} can implement this
+ * interface to hook into the serialization process.
+ */
+public interface AnnotatedJsonObject {
+
+	/**
+	 * This function is called <i>before</i> writing the annotated object.
+	 */
+	void onJsonWrite();
+
+	/**
+	 * This function is called <i>after</i> reading the annotated object.
+	 */
+	void onJsonRead();
+
+}

src/main/java/com/badlogic/gdx/json/AnnotatedJsonSerializer.java

@@ -73,6 +73,10 @@ public AnnotatedJsonSerializer(Json json, Class<T> clazz) {
 	@Override
 	public void write(Json json, T object, Class knownType) {
 
+		if (AnnotatedJsonObject.class.isAssignableFrom(clazz)) {
+			((AnnotatedJsonObject) object).onJsonWrite();
+		}
+
 		json.writeObjectStart();
 
 		if (annotation.dynamic()) {
@@ -266,6 +270,10 @@ public T read(Json json, JsonValue jsonData, Class type) {
 				}
 			}
 
+			if (AnnotatedJsonObject.class.isAssignableFrom(clazz)) {
+				((AnnotatedJsonObject) object).onJsonRead();
+			}
+
 			return object;
 
 		} catch (ReflectionException | ClassNotFoundException e) {
@@ -308,7 +316,21 @@ private void readObject(Json json, JsonValue jsonData, T object, FieldAdapter ad
 				value = JsonFloatSerializer.decodeDoubleBits(
 						json.readValue(accessible.getName(), String.class, jsonData), accessible.get(object));
 			} else {
-				value = json.readValue(accessible.getName(), fieldType, componentType, jsonData);
+				try {
+					value = json.readValue(accessible.getName(), fieldType, componentType, jsonData);
+				} catch (SerializationException e) {
+					// attempt to load again, using bit decoder - this allows loading of existing
+					// data after an encodeFP() annotation property has been removed
+					if (fieldType.equals(float.class)) {
+						value = JsonFloatSerializer.decodeFloatBits(
+								json.readValue(accessible.getName(), String.class, jsonData), accessible.get(object));
+					} else if (fieldType.equals(double.class)) {
+						value = JsonFloatSerializer.decodeDoubleBits(
+								json.readValue(accessible.getName(), String.class, jsonData), accessible.get(object));
+					} else {
+						throw new SerializationException(e);
+					}
+				}
 			}
 
 			if (value == null) {

src/main/java/com/badlogic/gdx/json/JsonArraySerializer.java

@@ -8,8 +8,6 @@
  * Implementation of {@link com.badlogic.gdx.utils.Json.Serializer} to serialize {@link Array} containers.
  *
  * This is used internally by {@link AnnotatedJsonSerializer}.
- *
- * @see {@link AnnotatedJsonSerializer}
  */
 class JsonArraySerializer<V> implements Json.Serializer<Array<?>> {
 

src/main/java/com/badlogic/gdx/json/JsonMapSerializer.java

@@ -10,8 +10,6 @@
  * Implementation of {@link com.badlogic.gdx.utils.Json.Serializer} to serialize {@link Map} containers.
  *
  * This is used internally by {@link AnnotatedJsonSerializer}.
- *
- * @see {@link AnnotatedJsonSerializer}
  */
 class JsonMapSerializer<K, V> implements Json.Serializer<Iterable<?>> {
 
@@ -81,7 +79,7 @@ public Iterable<?> read(Json json, JsonValue jsonData, Class type) {
 		return values;
 	}
 
-	public interface KeyValueConsumer<M, K, V> {
+	interface KeyValueConsumer<M, K, V> {
 		void accept(M map, K key, V value);
 	}