de.pawlidi.restgithub.rest.converter.GsonConverter.java Source code

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Here is the source code for de.pawlidi.restgithub.rest.converter.GsonConverter.java

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/*
 * Copyright (C) 2016 Maximilian Pawlidi
 *
 * 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 de.pawlidi.restgithub.rest.converter;

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.nio.charset.Charset;

import com.google.gson.Gson;
import com.google.gson.TypeAdapter;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;

import okhttp3.MediaType;
import okhttp3.RequestBody;
import okhttp3.ResponseBody;
import okio.Buffer;
import retrofit2.Converter;
import retrofit2.Retrofit;

/**
 * 
 * @author PAWLIDIM
 *
 */
public final class GsonConverter extends Converter.Factory implements IConverter {

    private Gson gson;

    public GsonConverter() {
        super();
        this.gson = new Gson();
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * retrofit2.Converter.Factory#responseBodyConverter(java.lang.reflect.Type,
     * java.lang.annotation.Annotation[], retrofit2.Retrofit)
     */
    @Override
    public Converter<ResponseBody, ?> responseBodyConverter(Type type, Annotation[] annotations,
            Retrofit retrofit) {
        return new ResponseBodyConverter<>(gson.getAdapter(TypeToken.get(type)));
    }

    private class ResponseBodyConverter<T> implements Converter<ResponseBody, T> {
        private final TypeAdapter<T> adapter;

        private ResponseBodyConverter(TypeAdapter<T> adapter) {
            super();
            this.adapter = adapter;
        }

        @Override
        public T convert(ResponseBody value) throws IOException {
            JsonReader jsonReader = gson.newJsonReader(value.charStream());
            try {
                return adapter.read(jsonReader);
            } finally {
                value.close();
            }
        }

    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * retrofit2.Converter.Factory#requestBodyConverter(java.lang.reflect.Type,
     * java.lang.annotation.Annotation[], java.lang.annotation.Annotation[],
     * retrofit2.Retrofit)
     */
    @Override
    public Converter<?, RequestBody> requestBodyConverter(Type type, Annotation[] parameterAnnotations,
            Annotation[] methodAnnotations, Retrofit retrofit) {
        return new RequestBodyConverter<>(gson.getAdapter(TypeToken.get(type)));
    }

    private class RequestBodyConverter<T> implements Converter<T, RequestBody> {

        private final TypeAdapter<T> adapter;

        public RequestBodyConverter(TypeAdapter<T> adapter) {
            this.adapter = adapter;
        }

        @Override
        public RequestBody convert(T value) throws IOException {
            Buffer buffer = new Buffer();
            Writer writer = new OutputStreamWriter(buffer.outputStream(), Charset.forName(UTF_8));
            JsonWriter jsonWriter = gson.newJsonWriter(writer);
            adapter.write(jsonWriter, value);
            jsonWriter.close();
            return RequestBody.create(MediaType.parse(GIT_HUB_MEDIA_TYPE), buffer.readByteString());
        }

    }
}