ApiService.java

public interface ApiService {

  @GET(ApiConstants.GET_QUESTIONS_URL)
  Observable<HttpResult<List<Question>>> getQuestions();
  }
  
  public interface CacheProviders {
  @LifeCache(duration = 7, timeUnit = TimeUnit.DAYS)
  Observable<Reply<List<Question>>> getCachedQuestions(Observable<List<Question>> items,
      EvictDynamicKey evictDynamicKey);
}

httpdata.java

public class httpData {
  private static File cacheDirectory = Utils.getcacheDirectory();
    private static final CacheProviders providers = new RxCache.Builder()
        .persistence(cacheDirectory, new GsonSpeaker())
        .using(CacheProviders.class);

    public httpData(ApiService mApiService){
        apiService = mApiService;
    }

    public void getQuiz(String sexe, boolean isload, Observer<List<Question>> observer) {
        Observable observable = apiService.getQuestions().map(new HttpResultFunc<List<Question>>());
        Observable observableCache = providers.getCachedQuestions(observable,
            new EvictDynamicKey(isload)).map(
            new HttpResultFuncCached<List<Question>>());
        setSubscribe(observableCache, observer);
    }

    public static <T> void setSubscribe(Observable<T> observable, Observer<T> observer) {
        observable.subscribeOn(Schedulers.io())
            .unsubscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(observer);
    }
    private  class HttpResultFunc<T> implements Function<HttpResult<T>, T>{

        @Override public T apply(HttpResult<T> tHttpResult) throws Exception {
            if (tHttpResult.getRequestResul()) {
                throw new RuntimeException();
            }
            return tHttpResult.getData();
        }
    }

    private  class HttpResultFuncCached<T> implements Function<Reply<T>, T> {
            @Override public T apply(Reply<T> httpResult) throws Exception  {
            return httpResult.getData();
        }
    }
}

HttpResult.java

public class HttpResult<T> {
    public Boolean requestResult;
    public T data;
    public static final String SUCCESS = "success";
    public static final String Fail = "Fail";
    public HttpResult(Boolean requestResult, T data) {
        this.requestResult = requestResult;
        this.data = data;
    }

    public Boolean getRequestResul() {
        return requestResult;
    }

    public void setRequestTime(Boolean requestResult) {
        this.requestResult = requestResult;
    }

    public T getData() {
        return data;
    }

    public void setData(T data) {
        this.data = data;
    }
}

Interactor.java

 public void performGetQuiz(String sexe, boolean isload, OnDataListListener callback) {
    mData.getQuiz(sexe, isload, new Observer<List<Question>>() {

      @Override public void onSubscribe(Disposable d) {
      }
      @Override public void onNext(List<Question> question) {
        Timber.d("onNext");
        Timber.d(question.get(0).getDesignation());
        callback.onSuccess(question);
      }

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

      @Override public void onComplete() {
        Timber.d("onComplete");
      }
    });
  }

Question.java

public class Question {

    @SerializedName(Constants.ID)
    private String id;
    @SerializedName(Constants.DESIGNATION)
    private String designation;
    @SerializedName(Constants.ANSWERS)
    @Nullable
    private ArrayList<QuestionAnswers> answers;

    public Question(String id, String designation, ArrayList<QuestionAnswers> answers) {
        this.answers = answers;
        this.id = id;
        this.designation = designation;
    }

QuizPresenter.java

...
elInteractor.performGetQuiz(Gender, isload, this);
...