com.google.api.client.json.gson.GsonFactory.java Source code

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Here is the source code for com.google.api.client.json.gson.GsonFactory.java

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/*
 * Copyright (c) 2011 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.api.client.json.gson;

import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.JsonGenerator;
import com.google.api.client.json.JsonParser;
import com.google.api.client.util.Beta;
import com.google.api.client.util.Charsets;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.StringReader;
import java.io.Writer;
import java.nio.charset.Charset;

/**
 * Low-level JSON library implementation based on GSON.
 *
 * <p>
 * Implementation is thread-safe, and sub-classes must be thread-safe. For maximum efficiency,
 * applications should use a single globally-shared instance of the JSON factory.
 * </p>
 *
 * @since 1.3
 * @author Yaniv Inbar
 */
public class GsonFactory extends JsonFactory {

    /**
     * {@link Beta} <br/>
     * Returns a global thread-safe instance.
     *
     * @since 1.16
     */
    @Beta
    public static GsonFactory getDefaultInstance() {
        return InstanceHolder.INSTANCE;
    }

    /** Holder for the result of {@link #getDefaultInstance()}. */
    @Beta
    static class InstanceHolder {
        static final GsonFactory INSTANCE = new GsonFactory();
    }

    @Override
    public JsonParser createJsonParser(InputStream in) {
        // TODO(mlinder): Parser should try to detect the charset automatically when using GSON
        // http://code.google.com/p/google-http-java-client/issues/detail?id=6
        return createJsonParser(new InputStreamReader(in, Charsets.UTF_8));
    }

    @Override
    public JsonParser createJsonParser(InputStream in, Charset charset) {
        if (charset == null) {
            return createJsonParser(in);
        }
        return createJsonParser(new InputStreamReader(in, charset));
    }

    @Override
    public JsonParser createJsonParser(String value) {
        return createJsonParser(new StringReader(value));
    }

    @Override
    public JsonParser createJsonParser(Reader reader) {
        return new GsonParser(this, new JsonReader(reader));
    }

    @Override
    public JsonGenerator createJsonGenerator(OutputStream out, Charset enc) {
        return createJsonGenerator(new OutputStreamWriter(out, enc));
    }

    @Override
    public JsonGenerator createJsonGenerator(Writer writer) {
        return new GsonGenerator(this, new JsonWriter(writer));
    }
}