FilterButtonPresenter

FilterButtonPresenter.java

@ViewScope // dagger 2 scope
class FilterButtonPresenter implements Presenter<FilterButtonState, StateView<FilterButtonState>> {

  final AccountInteractor accountInteractor;
  Subscription subscription;

  @Inject // dagger 2 dependency injection
  FilterButtonPresenter(AccountInteractor accountInteractor){
    this.accountInteractor = accountInteractor;
  }

  @Override
  void onStart(StateView<FilterButtonState> view){
    subscription = accountInteractor.isUserLoggedIn()
                    .map(isUserLoggedIn -> new FilterButtonState(isUserLoggedIn))
                    .subscribe(view::updateState);
  }

  @Override
  void onStop(){
    subscription.unsubscribe();
  }
  
  @AllArgsConstructor  // lombok
  static class FilterButtonState {
    final boolean enabled;
  }
}