com.google.devtools.moe.client.gson.AutoValueGsonAdapter.java Source code

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Here is the source code for com.google.devtools.moe.client.gson.AutoValueGsonAdapter.java

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/*
 * Copyright (c) 2015 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.devtools.moe.client.gson;

import com.google.gson.Gson;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.reflect.TypeToken;

import java.lang.reflect.Modifier;

/**
 * A Gson {@link TypeAdapterFactory} to support {@code @AutoValue}
 */
public final class AutoValueGsonAdapter implements TypeAdapterFactory {
    private static final String AUTOVALUE_PREFIX = ".AutoValue_";

    @Override
    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
        Class<?> type = typeToken.getRawType();
        if (!Modifier.isAbstract(type.getModifiers())) {
            return null; // AutoValues are never concrete types.
        }
        try {
            Class<?> implType = Class.forName(implementationName(type));
            @SuppressWarnings("unchecked")
            TypeAdapter<T> reflectiveDelegate = (TypeAdapter<T>) gson.getAdapter(implType);
            // TODO(cgruber) Discover a builder and supply a builder-aware adapter.
            return new AutoValueTypeAdapter<T>(gson, reflectiveDelegate, implType);
        } catch (ClassNotFoundException | NoClassDefFoundError e) {
            return null; // Not an AutoValue or no AutoValue implementation class was generated.
        }
    }

    private static String implementationName(Class<?> type) {
        String packageName = type.getPackage().getName();
        String className = type.getName().substring(packageName.length() + 1).replace('$', '_');
        return packageName + AUTOVALUE_PREFIX + className;
    }
}