io.apptik.comm.jus.converter.GsonConverterFactory.java Source code

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Here is the source code for io.apptik.comm.jus.converter.GsonConverterFactory.java

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/*
 * Copyright (C) 2015 AppTik Project
 * Copyright (C) 2015 Square, 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 io.apptik.comm.jus.converter;

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

import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

import io.apptik.comm.jus.Converter;
import io.apptik.comm.jus.NetworkRequest;
import io.apptik.comm.jus.NetworkResponse;

/**
 * A {@linkplain Converter.Factory converter} which uses Gson for JSON.
 * <p/>
 * This converter assumes that it can handle all types.
 * If you are using retro-jus mixing JSON serialization with
 * something else (such as protocol buffers), you must add this instance
 * last to allow the other converters a chance to see their types.
 */
public final class GsonConverterFactory extends Converter.Factory {
    /**
     * Create an instance using a default {@link Gson} instance for conversion. Encoding to JSON and
     * decoding from JSON (when no charset is specified by a header) will use UTF-8.
     */
    public static GsonConverterFactory create() {
        return create(new Gson());
    }

    /**
     * Create an instance using {@code gson} for conversion. Encoding to JSON and
     * decoding from JSON (when no charset is specified by a header) will use UTF-8.
     */
    public static GsonConverterFactory create(Gson gson) {
        return new GsonConverterFactory(gson);
    }

    private final Gson gson;

    public GsonConverterFactory(Gson gson) {
        if (gson == null)
            throw new NullPointerException("gson == null");
        this.gson = gson;
    }

    @Override
    public Converter<NetworkResponse, ?> fromResponse(Type type, Annotation[] annotations) {
        TypeAdapter<?> adapter = gson.getAdapter(TypeToken.get(type));
        return new GsonResponseConverter<>(adapter);
    }

    @Override
    public Converter<?, NetworkRequest> toRequest(Type type, Annotation[] annotations) {
        TypeAdapter<?> adapter = gson.getAdapter(TypeToken.get(type));
        return new GsonRequestConverter<>(gson, adapter);
    }
}