ResponseWithErrorHandling.java

public abstract class ResponseWithErrorHandling<R, E> implements Callback<ResponseBody> {
    private Type responseType;
    private Type errorType;

    public abstract void onResponseRequest(Call<ResponseBody> call, R response);

    public abstract void onErrorRequest(Call<ResponseBody> call, E error);

    public abstract void onFailureRequest(Call<ResponseBody> call, Throwable error);

    protected ResponseWithErrorHandling() {
        this.responseType = ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];
        this.errorType = ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[1];
    }

    @Override
    public final void onResponse(@NonNull Call<ResponseBody> call, @NonNull Response<ResponseBody> response) {

        try {

            if (response.isSuccessful()) {
                R mResponse = new Gson().fromJson(response.body().string(), responseType);
                onResponseRequest(call, mResponse);

            } else {
                E mError = new Gson().fromJson(response.errorBody().string(), errorType);
                onErrorRequest(call, mError);

            }

        } catch (Exception e) {
            e.printStackTrace();
            onFailureRequest(call, e);
        }
    }

    @Override
    public final void onFailure(@NonNull Call<ResponseBody> call, @NonNull Throwable t) {
        onFailureRequest(call, t);
    }
}