public class RetrofitUtils {
    private static Retrofit wsRetrofit;

    private static final Retrofit getWSRetrofit() {
        if (wsRetrofit == null) {

            HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
            interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
            OkHttpClient client = new OkHttpClient.Builder().addInterceptor(interceptor).build();

            wsRetrofit = new Retrofit.Builder()
                    .baseUrl(WebServices.BASE_URL)
                    .client(client)
                    .addConverterFactory(GsonConverterFactory.create())
                    .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                    .build();
        }
        return wsRetrofit;
    }

    public static final WebServices getWebServices() {
        return getWSRetrofit().create(WebServices.class);
    }

    public static <T> void call(Observable<T> call, final RetrofitCallback<T> callback) {
        call(call, null, callback);
    }

    public static <T> void call(Observable<T> call, final CompositeDisposable disposableContainer, final RetrofitCallback<T> callback) {
        call
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Observer<T>() {
                    @Override
                    public void onSubscribe(Disposable d) {
                        if (disposableContainer != null)
                            disposableContainer.add(d);
                    }

                    @Override
                    public void onNext(T t) {
                        callback.onSuccess(t);
                    }

                    @Override
                    public void onError(Throwable e) {
                        callback.onError(e);
                    }

                    @Override
                    public void onComplete() {

                    }
                });
    }
}