Observer pattern sample

articleService.java

PublishProcessor<List<Article>> articleList = PublishProcessor.create();

@Override
public Completable getArticles() {
    return remoteDataSource.getArticles()
            .flatMapCompletable(articles -> localDataSource
                    .saveArticles(articles)
                    .doOnSuccess(articleList::onNext))
}

public Observable<List<Article>> observeArticles() {
   return articleList;
}

ArticleViewModel.java

///  ArticleViewModel.java

disposables.addAll(
  articleService.getArticles()
  .subscribeOn(Schedular.io())
  .subscribe(() -> { }, e -> {}),
  articleService.observeArticles()
  .toSingle()
  .observeOn(Android.mainthread())
  .subscribe(list -> view::bind)
);