public class SolidClient {

    private static SolidService service;
    private static Retrofit retrofit;

    private static SolidService createService() {
        return getRetrofit().create(SolidService.class);
    }

    public static Retrofit getRetrofit() {
        if (retrofit == null) {
            retrofit = new Retrofit.Builder()
                    .client(getOkHttp())
                    .addConverterFactory(MoshiConverterFactory.create())
                    .baseUrl("http://www.mocky.io/")
                    .build();
        }
        return retrofit;
    }

    private static OkHttpClient getOkHttp() {
        return new OkHttpClient.Builder()
                .connectTimeout(30, TimeUnit.SECONDS)
                .readTimeout(30, TimeUnit.SECONDS)
                .writeTimeout(30, TimeUnit.SECONDS)
                .addInterceptor(new HttpLoggingInterceptor()
                        .setLevel(HttpLoggingInterceptor.Level.BODY))
                .build();
    }

    private static SolidService getService() {
        return service == null ? service = createService() : service;
    }


    public static void getListOfMalls(Callback<GetListOfMallsResponse> cb) {
        getService().getListOfMalls().enqueue(cb);
    }
}