RxJava - Getting Started

Nowadays applications are getting increasingly interconnected. Web Oriented Architecture or Micro-Service Architecture for example show there's a growing trend that integrating multiple different web services at different scale.

How to compose or aggregate all of these interactions in a usable result ; but especially how to implement it in a meaningful and readable code, with loose coupling and without temporal coupling ?

RxJava offers an elegant way to write synchronous and asynchronous code with enhanced composition capabilities. In this lightning talk we will present basic concepts of Rx (Reactive eXtensions).

David Wursteisen - Brice Dutheil / Human Talks Paris / September 9th 2014
Video of this presentation is on parleys in French :
https://www.parleys.com/tutorial/rxjava-getting-started-1

Transcript

1. RxJava Getting Started Brice Dutheil / David Wursteisen
2. Brice Dutheil @BriceDutheil Indep, Devoxx France, Hackergarten Paris Qui sommes nous ? David Wursteisen @dwursteisen
3. Il était une fois...
4. Il était une fois...
5. Systèmes distribués
6. Systèmes distribués
7. Systèmes distribués
8. Systèmes distribués
9. Systèmes distribués The Internet
10. Systèmes distribués
11. Systèmes distribués
12. RxJava
13. Obervable
14. Obervable
15. Obervable
16. Obervable
17. Observable Observable.from(1, 2, 3, 4)
18. Observable Observable.from(1, 2, 3, 4) Observable.from(asyncTask.getFuture())
19. Observable Observable.from(1, 2, 3, 4) Observable.from(asyncTask.getFuture()) Observable.range(1, 4400)
20. Observable Observable.from(1, 2, 3, 4) Observable.from(asyncTask.getFuture()) Observable.range(1, 4400) Observable.timer(0, 5, TimeUnit.SECONDS)
21. Observable Observable.from(1, 2, 3, 4) Observable.from(asyncTask.getFuture()) Observable.range(1, 4400) Observable.timer(0, 5, TimeUnit.SECONDS) Observable.create(...)
22. Observable Observable.from(1, 2, 3, 4) Observable.from(asyncTask.getFuture()) Observable.range(1, 4400) Observable.timer(0, 5, TimeUnit.SECONDS) Observable.create(...) Observable.from(anIterable) Observable.just(73) Observable.error(new Exception()) Observable.empty() ...
23. Observable Observable<Message> Observable<Result> Observable<Interaction>
24. Subscriber Observable.range(1, 4400)
25. Subscriber Observable.range(1, 4400) .subscribe( onNext )
26. Subscriber Observable.range(1, 4400) .subscribe( System.out::println )
27. Subscriber Observable.range(1, 4400) .subscribe( System.out::println, onError )
28. Subscriber Observable.range(1, 4400) .subscribe( System.out::println, System.err::println )
29. Subscriber Observable.range(1, 4400) .subscribe( System.out::println, System.err::println, onCompleted )
30. Subscriber Observable.range(1, 4400) .subscribe( System.out::println, System.err::println, () -> System.out.println(“finished”) )
31. Diagrammes Marble
32. Diagrammes Marble
33. Diagrammes Marble
34. Diagrammes Marble
35. Diagrammes Marble
36. Diagrammes Marble
37. Diagrammes Marble
38. Diagrammes Marble
39. Opérateurs Observable.from(1, 2, 3, 4)
40. Opérateurs Observable.from(1, 2, 3, 4) .filter(predicate)
41. Opérateurs Observable.from(1, 2, 3, 4) .filter((i) -> (i % 2) == 0)
42. Opérateurs Observable.from(1, 2, 3, 4) .filter((i) -> (i % 2) == 0) .subscribe(System.out::println)
43. Opérateurs Observable.from(1, 2, 3, 4) .filter((i) -> (i % 2) == 0) .subscribe(System.out::println)
44. Opérateurs Observable.from(1, 2, 3, 4) .filter((i) -> (i % 2) == 0) .subscribe(System.out::println) 2
45. Opérateurs Observable.from(1, 2, 3, 4) .filter((i) -> (i % 2) == 0) .subscribe(System.out::println) 2 4
46. Opérateurs Observable.from(1, 2, 3, 4) .take(2) .subscribe(System.out::println);
47. Opérateurs Observable.from(1, 2, 3, 4) .take(2) .subscribe(System.out::println); 1 2
48. Opérateurs Observable.from(1, 2, 3, 4) .map((i) -> i * 10) .subscribe(System.out::println);
49. Opérateurs Observable.from(1, 2, 3, 4) .map((i) -> i * 10) .subscribe(System.out::println); 10 20 30 40
50. Composition
51. Composition
52. Composition
53. Composition couleurs formes
54. Programmation synchrone observableReadingSynchronously(“strings.txt”) .take(10) .delay(1, SECONDS) .map(parse()) .map(n -> “=> ” + n)) .subscribe(to_the_view())
55. Programmation synchrone main
56. Programmation synchrone observableReadingSynchronously(“strings.txt”) .take(10) .delay(1, SECONDS) .map(parse()) .map(n -> “=> ” + n)) .subscribe(to_the_view())
57. Programmation asynchrone Computation IO UI main source
58. Programmation asynchrone Computation IO UI main source ... .subscribeOn(Schedulers.io())
59. Programmation asynchrone Computation IO UI main source .take(...) .subscribeOn(Schedulers.io())
60. Programmation asynchrone Computation IO UI main .delay(..., Schedulers.computation())
61. Programmation asynchrone Computation IO UI main .delay(..., Schedulers.computation()) .map(...)
62. Programmation asynchrone Computation IO UI main .observeOn(Schedulers.from(...)) .map(...)
63. Programmation asynchrone Computation IO UI main .observeOn(Schedulers.from(...)) .map(...) .subscribe(...)
64. Programmation asynchrone observableReadingSynchronously(“strings.txt”) .subscribeOn(scheduler) .take(10) .delay(1, SECONDS, scheduler) .map(parse()) .observeOn(scheduler) .map(n -> “=> ” + n)) .subscribe(to_the_view())
65. Programmation asynchrone observableReadingSynchronously(“strings.txt”) .subscribeOn(Schedulers.io()) .take(10) .delay(1, SECONDS, Schedulers.computation()) .map(parse()) .observeOn(Schedulers.from(uiExecutor())) .map(n -> “=> ” + n)) .subscribe(to_the_view())
66. Aller plus loin Séquence finie & infinie Unsubscribe BackPressure Reactive Streams Hot & Cold observable
67. Aller plus loin Séquence finie & infinie Unsubscribe BackPressure Reactive Streams Hot & Cold observable
68. Aller plus loin Séquence finie & infinie Unsubscribe BackPressure Reactive Streams Hot & Cold observable
69. Aller plus loin Séquence finie & infinie Unsubscribe BackPressure Reactive Streams Hot & Cold observable
70. Aller plus loin Séquence finie & infinie Unsubscribe BackPressure Reactive Streams Hot & Cold observable
71. Aller plus loin Séquence finie & infinie Unsubscribe BackPressure Reactive Streams Hot & Cold observable
72. Questions ?