Reactive 4TW

Reactive programming is a new big thing for a couple of years now, but it also shrouded with a distrust as any new technology with mindblowing concepts. Lets pretend together that you didn't hear about Reactive and start learning it from scratch!

Transcript

1. Introduction to Reactive principles with RxJava @AlexeyBuzdin Reactive 4TW!
2. @AlexeyBuzdin Developer / Trainer at
3. this page was intentionally left blank… Reactive
5. Good?
6. or Bad?
7. Scary
8. but Productive!
9. reactive /rɪˈaktɪv/ 1. showing a response to a stimulus. "pupils are reactive to light" 2. acting in response to a situation rather than creating or controlling it. "a proactive rather than a reactive approach"
10. reactive /rɪˈaktɪv/ 1. showing a response to a stimulus. "pupils are reactive to light" 2. acting in response to a situation rather than creating or controlling it. "a proactive rather than a reactive approach"
12. Observer Observable Object
13. Observer Observable Object
14. Observer Observable Object
15. Observer Observable Object
16. Observable
17. Observer
18. Object(Event)
19. programming with asynchronous data streams Reactive programming is
20. List<Ball> balls = Collections.singletonList(new Ball()); Observable<Ball> pitcher = Observable.from(balls); Observer<Ball> batter = new Observer<Ball>() { @Override public void onCompleted() { /* Score! */ } @Override public void onError(Throwable e) { /* Shame */ } @Override public void onNext(Ball ball) { /* Hit! */ } }; pitcher.subscribe(batter);
21. List<Ball> balls = Collections.singletonList(new Ball()); Observable<Ball> pitcher = Observable.from(balls); Observer<Ball> batter = new Observer<Ball>() { @Override public void onCompleted() { /* Score! */ } @Override public void onError(Throwable e) { /* Shame */ } @Override public void onNext(Ball ball) { /* Hit! */ } }; pitcher.subscribe(batter);
22. List<Ball> balls = Collections.singletonList(new Ball()); Observable<Ball> pitcher = Observable.from(balls); Observer<Ball> batter = new Observer<Ball>() { @Override public void onCompleted() { /* Score! */ } @Override public void onError(Throwable e) { /* Shame */ } @Override public void onNext(Ball ball) { /* Hit! */ } }; pitcher.subscribe(batter);
23. List<Ball> balls = Collections.singletonList(new Ball()); Observable<Ball> pitcher = Observable.from(balls); Observer<Ball> batter = new Observer<Ball>() { @Override public void onCompleted() { /* Score! */ } @Override public void onError(Throwable e) { /* Shame */ } @Override public void onNext(Ball ball) { /* Hit! */ } }; pitcher.subscribe(batter);
24. List<Ball> balls = /* Infinite balls */ Observable<Ball> pitcher = Observable.from(balls); Observer<Ball> batter = new Observer<Ball>() { @Override public void onCompleted() { /* Score! */ } @Override public void onError(Throwable e) { /* Shame */ } @Override public void onNext(Ball ball) { /* Hit! */ } }; pitcher.subscribe(batter);
25. programming with asynchronous data streams Reactive programming is
27. Everything can be a Stream: - collections - user inputs - hardware - properties - caches - data structures - etc.
28. Collections List< > balls = Lists.emptyList();
29. Everything can be a Stream: - collections - user inputs - hardware - properties - caches - data structures - etc.
30. UserInput Button btw = new Button(ctx); btn.setOnClickListener(e -> { // Do something })
31. Everything can be a Stream: - collections - user inputs - hardware - properties - caches - data structures - etc.
32. Hardware LocationManager mng = (LocationManager) getSystemService(Context.LOCATION_SERVICE); LocationListener listener = new LocationListener() { public void onLocationChanged(Location location) { // Do something } ….. }; locationManager.requestLocationUpdates (LocationManager.NETWORK_PROVIDER, 0, 0, listener);
33. Everything can be a Stream: - collections - user inputs - hardware - properties - caches - data structures - etc.
34. UserInput SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this); prefs.getBoolean("keystring", true);
35. Everything can be a Stream: - collections - user inputs - hardware - properties - caches - data structures - etc.
36. DataBase select().from(t).where(row(t.a, t.b).eq(1, 2));
37. Everything can be a Stream: - collections - user inputs - hardware - properties - caches - data structures - etc.
38. Data Structures
39. Everything can be a Stream: - collections - user inputs - hardware - properties - caches - data structures - etc.
40. …and what next?
41. Operations!
42. Operations! - map - filter - zip - groupBy - collect - flatMap - etc.
43. RealLife RX RxView.clickEvents(tapBtn) .map(new Func1<ViewClickEvent, Integer>() { @Override public Integer call(ViewClickEvent onClickEvent) { log("GOT A TAP"); return 1; } }) .buffer(2, TimeUnit.SECONDS) .observeOn(AndroidSchedulers.mainThread()) .subscribe( /* Observer here */)
44. programming with asynchronous data streams Reactive programming is
46. programming with asynchronous data streams Reactive programming is
47. RealLife RX
50. Try it Out!
51. Q&A