presenter

public class InfoPresenterImpl extends MvpBasePresenter<InfoView> implements InfoPresenter {

  @NonNull
  private final InfoModel model;
  @Nullable
  private Subscription observing;
  @Nullable
  private Subscription updating;

  public InfoPresenterImpl(@NonNull InfoModel model) {
    this.model = model;
  }

  @Override
  public void attachView(InfoView attached) {
    super.attachView(attached);
    if (!isSubscribed(observing)) {
      observing = model.observeInfo().subscribe(s -> {
        InfoView view = getView();
        if (isViewAttached()) {
          view.setData(s);
          view.showContent();
        }
      }, t -> {
          if (isViewAttached()) {
            getView().showError(t, false);
          }
        });
    }
  }

  @Override
  public void detachView(boolean retainInstance) {
    super.detachView(retainInstance);
    if (!retainInstance) {
      tryToUnsubscribe(observing);
      tryToUnsubscribe(updating);
    }
  }

  @Override
  @AnyThread
  public void loadInformation(boolean pullToRefresh) {
    getView().showLoading(pullToRefresh);
    tryToUnsubscribe(updating);
    updating = model.updateInfo().subscribe(ignored -> { }, t -> {
      if (isViewAttached()) {
        getView().showError(t, true);
      }
    });
  }

  private void tryToUnsubscribe(@Nullable Subscription subscription) {
    if (isSubscribed(subscription)) {
      subscription.unsubscribe();
    }
  }

  private boolean isSubscribed(@Nullable Subscription subscription) {
    return subscription != null && !subscription.isUnsubscribed();
  }

}