com.google.gson.internal.bind.JsonAdapterAnnotationTypeAdapterFactory Maven / Gradle / Ivy
/*
* 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")
@Override
public TypeAdapter create(Gson gson, TypeToken targetType) {
JsonAdapter annotation = targetType.getRawType().getAnnotation(JsonAdapter.class);
if (annotation == null) {
return null;
}
return (TypeAdapter) 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();
TypeAdapter typeAdapter;
if (TypeAdapter.class.isAssignableFrom(value)) {
Class> typeAdapterClass = (Class>) value;
typeAdapter = constructorConstructor.get(TypeToken.get(typeAdapterClass)).construct();
} else if (TypeAdapterFactory.class.isAssignableFrom(value)) {
Class typeAdapterFactory = (Class) value;
typeAdapter = constructorConstructor.get(TypeToken.get(typeAdapterFactory))
.construct()
.create(gson, fieldType);
} else {
throw new IllegalArgumentException(
"@JsonAdapter value must be TypeAdapter or TypeAdapterFactory reference.");
}
if (typeAdapter != null) {
typeAdapter = typeAdapter.nullSafe();
}
return typeAdapter;
}
}