Added Adapter Layering Feature (Java 6 Compatible)

gson/src/main/java/com/google/gson/Gson.java

@@ -127,7 +127,7 @@ public final class Gson {
   private final Map<TypeToken<?>, TypeAdapter<?>> typeTokenCache = new ConcurrentHashMap<TypeToken<?>, TypeAdapter<?>>();
 
   private final ConstructorConstructor constructorConstructor;
-  private final JsonAdapterAnnotationTypeAdapterFactory jsonAdapterFactory;
+  final JsonAdapterAnnotationTypeAdapterFactory jsonAdapterFactory;
 
   final List<TypeAdapterFactory> factories;
 
@@ -895,7 +895,9 @@ public <T> T fromJson(Reader json, Class<T> classOfT) throws JsonSyntaxException
   public <T> T fromJson(Reader json, Type typeOfT) throws JsonIOException, JsonSyntaxException {
     JsonReader jsonReader = newJsonReader(json);
     T object = (T) fromJson(jsonReader, typeOfT);
-    assertFullConsumption(object, jsonReader);
+    if (!ReflectiveTypeAdapterFactory.Adapter.class.isAssignableFrom(getAdapter(TypeToken.get(typeOfT)).getClass())) {
+      assertFullConsumption(object, jsonReader);
+    }
     return object;
   }
 

gson/src/main/java/com/google/gson/GsonBuilder.java

@@ -16,6 +16,22 @@
 
 package com.google.gson;
 
+import static com.google.gson.Gson.DEFAULT_COMPLEX_MAP_KEYS;
+import static com.google.gson.Gson.DEFAULT_ESCAPE_HTML;
+import static com.google.gson.Gson.DEFAULT_JSON_NON_EXECUTABLE;
+import static com.google.gson.Gson.DEFAULT_LENIENT;
+import static com.google.gson.Gson.DEFAULT_PRETTY_PRINT;
+import static com.google.gson.Gson.DEFAULT_SERIALIZE_NULLS;
+import static com.google.gson.Gson.DEFAULT_SPECIALIZE_FLOAT_VALUES;
+
+import com.google.gson.internal.$Gson$Preconditions;
+import com.google.gson.internal.ConstructorConstructor;
+import com.google.gson.internal.Excluder;
+import com.google.gson.internal.bind.ReflectiveTypeAdapterFactory;
+import com.google.gson.internal.bind.TreeTypeAdapter;
+import com.google.gson.internal.bind.TypeAdapters;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
 import java.lang.reflect.Type;
 import java.sql.Timestamp;
 import java.text.DateFormat;
@@ -26,21 +42,6 @@
 import java.util.List;
 import java.util.Map;
 
-import com.google.gson.internal.$Gson$Preconditions;
-import com.google.gson.internal.Excluder;
-import com.google.gson.internal.bind.TreeTypeAdapter;
-import com.google.gson.internal.bind.TypeAdapters;
-import com.google.gson.reflect.TypeToken;
-import com.google.gson.stream.JsonReader;
-
-import static com.google.gson.Gson.DEFAULT_COMPLEX_MAP_KEYS;
-import static com.google.gson.Gson.DEFAULT_ESCAPE_HTML;
-import static com.google.gson.Gson.DEFAULT_JSON_NON_EXECUTABLE;
-import static com.google.gson.Gson.DEFAULT_LENIENT;
-import static com.google.gson.Gson.DEFAULT_PRETTY_PRINT;
-import static com.google.gson.Gson.DEFAULT_SERIALIZE_NULLS;
-import static com.google.gson.Gson.DEFAULT_SPECIALIZE_FLOAT_VALUES;
-
 /**
  * <p>Use this builder to construct a {@link Gson} instance when you need to set configuration
  * options other than the default. For {@link Gson} with default configuration, it is simpler to
@@ -511,6 +512,36 @@ public GsonBuilder registerTypeAdapter(Type type, Object typeAdapter) {
     return this;
   }
 
+  /**
+   * Configures Gson for custom serialization and deserialization with Fill-in. Takes the type
+   * adapter, and wraps the result from the {@link TypeAdapter} into a {@link ReflectiveTypeAdapterFactory.Adapter}. Like
+   * {@link #registerTypeAdapter(Type, Object)}, it only applies to the type specified by
+   * the {@code type} parameter.
+   *
+   * @param baseType the type definition for the type adapter being registered
+   * @param objectAdapter This object must implement the {@link TypeAdapter} class
+   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
+   */
+  public GsonBuilder registerTypeAdapterWithFillIn(final Type baseType, Object objectAdapter) {
+   $Gson$Preconditions.checkArgument(objectAdapter instanceof TypeAdapter<?>);
+   final TypeAdapter<?> typeAdapter = (TypeAdapter<?>) objectAdapter;
+
+   factories.add(new TypeAdapterFactory() {
+     @Override
+     public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+       ConstructorConstructor constructorConstructor = new ConstructorConstructor(type, typeAdapter);
+       List<Type> typeList = new ArrayList<Type>();
+       typeList.add(baseType);
+       ReflectiveTypeAdapterFactory reflectiveTypeAdapterFactory =
+           new ReflectiveTypeAdapterFactory(constructorConstructor, gson.fieldNamingStrategy,
+               gson.excluder, gson.jsonAdapterFactory, typeList);
+       return reflectiveTypeAdapterFactory.create(gson, type);
+     }
+   });
+
+   return this;
+  }
+
   /**
    * Register a factory for type adapters. Registering a factory is useful when the type
    * adapter needs to be configured based on the type of the field being processed. Gson

gson/src/main/java/com/google/gson/InstanceCreatorWrapper.java

@@ -0,0 +1,32 @@
+package com.google.gson;
+
+import com.google.gson.stream.JsonReader;
+import java.lang.reflect.Type;
+
+/**
+ * Acts as a wrapper of the {@link InstanceCreator} interface for fill-in. Fulfills roughly the same
+ * functionality as the {@link com.google.gson.internal.ObjectConstructorWrapper} class. It doesn't
+ * break existing functionality by implementing {@code InstanceCreator} but when casted to this
+ * class, it can expose a method that accepts a {@code JsonReader} as a parameter, allowing fill-in
+ * functionality.
+ */
+public class InstanceCreatorWrapper<T> implements InstanceCreator<T> {
+
+  @Override
+  public T createInstance(Type type) {
+    return null;
+  }
+
+  /**
+   * If not defined, defaults to returning the result of {@link #createInstance}. This method is
+   * designed to help with creating Adapters with Fill-In. See {@link
+   * GsonBuilder#registerTypeAdapterFactory}.
+   *
+   * @param type the parameterized T represented as a {@link Type}.
+   * @param in the JsonReader from which to create the instance.
+   * @return a default object instance of type T.
+   */
+  public T createInstance(Type type, JsonReader in) {
+    return createInstance(type);
+  }
+}