/* * Copyright (C) 2014 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.google.gson.internal.bind; import com.google.gson.Gson; import com.google.gson.TypeAdapter; import com.google.gson.TypeAdapterFactory; import com.google.gson.annotations.JsonAdapter; import com.google.gson.internal.ConstructorConstructor; import com.google.gson.reflect.TypeToken; /** * Given a type T, looks for the annotation {@link JsonAdapter} and uses an instance of the * specified class as the default type adapter. * * @since 2.3 */ public final class JsonAdapterAnnotationTypeAdapterFactory implements TypeAdapterFactory { private final ConstructorConstructor constructorConstructor; public JsonAdapterAnnotationTypeAdapterFactory(ConstructorConstructor constructorConstructor) { this.constructorConstructor = constructorConstructor; } @SuppressWarnings("unchecked") public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> targetType) { JsonAdapter annotation = targetType.getRawType().getAnnotation(JsonAdapter.class); if (annotation == null) { return null; } return (TypeAdapter<T>) getTypeAdapter(constructorConstructor, gson, targetType, annotation); } @SuppressWarnings("unchecked") // Casts guarded by conditionals. static TypeAdapter<?> getTypeAdapter(ConstructorConstructor constructorConstructor, Gson gson, TypeToken<?> fieldType, JsonAdapter annotation) { Class<?> value = annotation.value(); if (TypeAdapter.class.isAssignableFrom(value)) { Class<TypeAdapter<?>> typeAdapter = (Class<TypeAdapter<?>>) value; return constructorConstructor.get(TypeToken.get(typeAdapter)).construct(); } if (TypeAdapterFactory.class.isAssignableFrom(value)) { Class<TypeAdapterFactory> typeAdapterFactory = (Class<TypeAdapterFactory>) value; return constructorConstructor.get(TypeToken.get(typeAdapterFactory)) .construct() .create(gson, fieldType); } throw new IllegalArgumentException( "@JsonAdapter value must be TypeAdapter or TypeAdapterFactory reference."); } }