Storing state

articleService.java

@Override
public Completable getArticles() {
    return remoteDataSource.getArticles()
            .flatMapCompletable(articles -> localDataSource
                    .saveArticles(articles);
}

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

LocalDataSource.java

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


LocalDataSource(ArticleDao articleDao) {
     this.articleDao = articleDao;
     articleDao.subscribeOn(Schedulars.io()).getAll().subscribe(articleList::onNext)
}

public Completable saveArticles(List<Article> article) {
    return Completable.fromAction(() -> articleDao.insert(article))
                      .doOnSuccess(articleList::onNext);
}

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