/*
* 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({"rawtypes", "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.");
}
}