使用RXJava 2异步读取/写入Realm

Question

My first implementation of an asynchronous operation using RXJava 2

Goal:

Get json data from the server with library Retrofit2 . If successful, then write the data to Realm and immediately after the record get the data back and send to the adapter of RecyclerView .

So, I realized all this in this way:

private void fetchChatsFromNetwork(int count, AccessDataModel accessDataModel) {

    String accessToken = accessDataModel.getAccessToken();

    MyApplication.getRestApi().getChats(count, accessToken, Constants.api_version)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribeWith(new DisposableSubscriber<ChatsModel>() {
                @Override
                public void onNext(ChatsModel chatsModel) {
                    if (chatsRepository.hasData()) {

                        chatsRepository.updateChatsData(chatsModel)
                                .subscribe(new DisposableObserver<ChatsModel>() {
                                    @Override
                                    public void onNext(ChatsModel localChatsModel) {
                                        Log.d(TAG, "DO, onSuccess updated!");
                                        iGetChatsCallback.onGetChatsSuccess(localChatsModel);
                                    }

                                    @Override
                                    public void onError(Throwable e) {
                                        Log.d(TAG, "DO, onError when update!");
                                        iGetChatsCallback.onGetChatsError(e.getMessage());
                                    }

                                    @Override
                                    public void onComplete() {
                                        dispose();
                                        Log.d(TAG, "DO, onComplete!");
                                    }
                                });

                    } else {
                        chatsRepository.insertChatsData(chatsModel)
                                .subscribe(new DisposableObserver<ChatsModel>() {
                                    @Override
                                    public void onNext(ChatsModel localChatsModel) {
                                        iGetChatsCallback.onGetChatsSuccess(localChatsModel);
                                        Log.d(TAG, "DO, onSuccess inserted!");
                                    }

                                    @Override
                                    public void onError(Throwable e) {
                                        iGetChatsCallback.onGetChatsError(e.getMessage());
                                        Log.d(TAG, "DO, onError when inserting!");
                                    }

                                    @Override
                                    public void onComplete() {
                                        dispose();
                                        Log.d(TAG, "DO, onComplete!");
                                    }
                                });
                    }
                }

                @Override
                public void onError(Throwable t) {
                    Log.d(TAG, "onError" + t.getMessage());
                }

                @Override
                public void onComplete() {
                    Log.d(TAG, "onComplete");
                }
            });
}

I write the data in Realm in the onNext() method of the subscriber MyApplication.getRestApi().GetChats()

Here is the entry code:

public Observable<ChatsModel> updateChatsData(final ChatsModel chatsModel) {

    return Observable.create(new ObservableOnSubscribe<ChatsModel>() {
        @Override
        public void subscribe(ObservableEmitter<ChatsModel> e) throws Exception {
            if (chatsModel != null) {
                realm.executeTransactionAsync(
                        realm -> realm.copyToRealmOrUpdate(chatsModel),
                        () -> {
                            Log.d(LOG_TAG, "Data success updated!");
                            ChatsModel localChatsModel = getAllChatsData();
                            e.onNext(localChatsModel);
                            e.onComplete();
                        },
                        error -> {
                            Log.d(LOG_TAG, "Update data failed!");
                            e.onError(error);
                        });
            }

        }
    });

}

The updateChatsData() writes asynchronously and declared in another class.

As you can see, the fetchChatsFromNetwork() method is written cumbersome or so it seems to me

Question:

Whether I am doing right or not, if not, how would that be correct?

Answer 1

private void fetchChatsFromNetwork(int count, AccessDataModel accessDataModel) {    
    String accessToken = accessDataModel.getAccessToken();
    Single<ChatsModel> chats = MyApplication.getRestApi().getChats(count, accessToken, Constants.api_version);
    chats.doOnNext((chats) -> {
        chatsRepository.insertOrUpdate(chats);
    }).subscribeOn(Schedulers.io())
    .subscribe();
}

And

public void updateChatsData(final ChatsModel chatsModel) {
    try(Realm realm = Realm.getDefaultInstance()) {
        realm.executeTransaction(r -> {
            r.insertOrUpdate(chatsModel);
        });
    }
}

And

public Flowable<List<ChatsModel>> getAllChatsData(Realm realm) {
    RealmQuery<ChatsModel> query = realm.where(ChatsModel.class);
    if(realm.isAutoRefresh()) {
        return query.findAllAsync().asFlowable().filter(RealmResults::isLoaded);
    } else {
        return Flowable.just(query.findAll());
    }
}