Абстракция над AudioPlayer

gistfile1.txt

// domainlayer
public interface AudioPlayer {
	Observable<Integer> play(String pathToFile);
	void stop();
}

// datalayer
public class AudioPlayerImpl implements AudioPlayer {

	private Context context;
	private MediaPlayer mp;

	public AudioPlayerImpl(Context context) {
		this.context = context;
	}

	@Override
	public Observable<Integer> play(String pathToFile) {
		return Observable.create(subscriber -> {
			stop();
			mp = MediaPlayer.create(context, Uri.parse(pathToFile));
			if (mp != null) {
				subscriber.onNext(mp.getAudioSessionId());
				mp.start();
				mp.setOnCompletionListener(mp1 -> {
					if (!subscriber.isUnsubscribed())
						subscriber.onCompleted();

				});
				mp.setOnErrorListener((mp1, what, extra) -> {
					if (!subscriber.isUnsubscribed())
						subscriber.onError(new MediaPlayerError(what, extra));
					return false;
				});
				subscriber.add(Subscriptions.create(this::stop));

			} else {
				//??
				subscriber.onCompleted();
			}

		});
	}

	@Override
	public void stop() {
		if (mp != null) {
			if (mp.isPlaying()) {
				mp.stop();
			}
			mp.release();
			mp = null;
		}
	}
}

// использование
public class PlayLastAudioUseCase extends GetCurrentOrLastAudioPath<Integer> {

	private AudioPlayer audioPlayer;

	@Inject
	public PlayLastAudioUseCase(SchedulersProvider provider, AudioRecordDP audioRecordDP,
								AudioPlayer audioPlayer) {
		super(provider,audioRecordDP);
		this.audioPlayer = audioPlayer;
	}

	@Override
	protected Observable<Integer> buildUseCaseObservable() {
		return getRecordPath()
				.concatMap(s -> audioPlayer.play(s));
	}
}