Example of a Rest Client using retrofit

RestClient.java

/**
 *  Created by ChrisC on 22/05/17.
 */

public enum RestClient {

    INSTANCE;


    transient Retrofit apiClient = new Retrofit.Builder()
            .baseUrl(BuildConfig.WS_SERVER)
            .client(getAPIKeyClient())
            .addConverterFactory(GsonConverterFactory.create())
            .build();

    WS service = apiClient.create(WS.class);

    public OkHttpClient getTokenClient() {
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);

        return new OkHttpClient.Builder()
                .addInterceptor(new TokenInterceptor())
                .addInterceptor(logging)
                .build();
    }

    public OkHttpClient getAPIKeyClient() {
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);

        return new OkHttpClient.Builder()
                .addInterceptor(new APIKeyInterceptor())
                .addInterceptor(logging)
                .build();
    }

    public OkHttpClient getLogClient() {
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);

        return new OkHttpClient.Builder()
                .addInterceptor(logging)
                .build();
    }


    public WS getApiService() {
        return service;
    }
}