ServiceCreator.java

package ua.kpi.ecampus.api.service;


import java.util.concurrent.TimeUnit;

import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;


/**
 * This class creates a new REST client with a given API_Endpoint.
 * <p>
 * Created by Administrator on 08.02.2016.
 */
public class ServiceCreator {

    private static final int TIMEOUT = 60;
    private static final int WRITE_TIMEOUT = 120;
    private static final int CONNECT_TIMEOUT = 10;

    public static final String API_ENDPOINT =
            "https://api-campus-kpi-ua.azurewebsites.net";

    private static final OkHttpClient.Builder CLIENT = new OkHttpClient
            .Builder();


    static {
        CLIENT.connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS);
        CLIENT.writeTimeout(WRITE_TIMEOUT, TimeUnit.SECONDS);
        CLIENT.readTimeout(TIMEOUT, TimeUnit.SECONDS);
    }

    private static Retrofit.Builder builder =
            new Retrofit.Builder()
                    .baseUrl(API_ENDPOINT)
                    .addConverterFactory(GsonConverterFactory.create())
                    .addCallAdapterFactory(RxJavaCallAdapterFactory.create());

    private static Interceptor interceptor = chain -> {
        Request original = chain.request();

        Request request = original.newBuilder()
                .header("Accept", "application/json")
                .header("Content-Type", "application/json")
                .method(original.method(), original.body())
                .build();

        return chain.proceed(request);
    };


    /**
     * Creates a retrofit service from an arbitrary class
     *
     * @param serviceClass Java interface of the retrofit service
     * @return retrofit service with defined endpoint
     */
    public static <S> S createService(Class<S> serviceClass) {
        CLIENT.interceptors().add(interceptor);
        Retrofit retrofit = builder.client(CLIENT.build()).build();
        return retrofit.create(serviceClass);
    }

    /**
     * Creates test service. For unit testing purposes.
     *
     * @param url endpoint
     * @param serviceClass Java interface of the retrofit service
     * @param <S>
     * @return test service
     */
    public static <S> S createTestService(String url, Class<S> serviceClass) {
        OkHttpClient httpClient = new OkHttpClient();
        Retrofit.Builder builder = new Retrofit.Builder().
                baseUrl(url)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create());
        builder.client(httpClient);
        S apiInterface = builder.build().create(serviceClass);
        return apiInterface;
    }
}