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
   

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2. Brice Dutheil
   @BriceDutheil
   Indep, Devoxx France,
   Hackergarten Paris
   Qui sommes nous ?
   David Wursteisen
   @dwursteisen
   

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3. Il était une fois...
   

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4. Il était une fois...
   

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5. Systèmes distribués
   

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6. Systèmes distribués
   

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7. Systèmes distribués
   

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8. Systèmes distribués
   

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9. Systèmes distribués
   The Internet
   

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10. Systèmes distribués
    

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11. Systèmes distribués
    

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12. RxJava
    

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13. Obervable
    

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14. Obervable
    

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15. Obervable
    

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16. Obervable
    

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17. Observable
    Observable.from(1, 2, 3, 4)
    

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18. Observable
    Observable.from(1, 2, 3, 4)
    Observable.from(asyncTask.getFuture())
    

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19. Observable
    Observable.from(1, 2, 3, 4)
    Observable.from(asyncTask.getFuture())
    Observable.range(1, 4400)
    

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20. Observable
    Observable.from(1, 2, 3, 4)
    Observable.from(asyncTask.getFuture())
    Observable.range(1, 4400)
    Observable.timer(0, 5, TimeUnit.SECONDS)
    

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21. Observable
    Observable.from(1, 2, 3, 4)
    Observable.from(asyncTask.getFuture())
    Observable.range(1, 4400)
    Observable.timer(0, 5, TimeUnit.SECONDS)
    Observable.create(...)
    

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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()
    ...
    

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23. Observable
    Observable
    Observable
    Observable
    

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24. Subscriber
    Observable.range(1, 4400)
    

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25. Subscriber
    Observable.range(1, 4400)
    .subscribe(
    onNext
    )
    

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26. Subscriber
    Observable.range(1, 4400)
    .subscribe(
    System.out::println
    )
    

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27. Subscriber
    Observable.range(1, 4400)
    .subscribe(
    System.out::println,
    onError
    )
    

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28. Subscriber
    Observable.range(1, 4400)
    .subscribe(
    System.out::println,
    System.err::println
    )
    

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29. Subscriber
    Observable.range(1, 4400)
    .subscribe(
    System.out::println,
    System.err::println,
    onCompleted
    )
    

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30. Subscriber
    Observable.range(1, 4400)
    .subscribe(
    System.out::println,
    System.err::println,
    () -> System.out.println(“finished”)
    )
    

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31. Diagrammes Marble
    

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32. Diagrammes Marble
    

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33. Diagrammes Marble
    

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34. Diagrammes Marble
    

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35. Diagrammes Marble
    

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36. Diagrammes Marble
    

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37. Diagrammes Marble
    

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38. Diagrammes Marble
    

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39. Opérateurs
    Observable.from(1, 2, 3, 4)
    

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40. Opérateurs
    Observable.from(1, 2, 3, 4)
    .filter(predicate)
    

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41. Opérateurs
    Observable.from(1, 2, 3, 4)
    .filter((i) -> (i % 2) == 0)
    

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42. Opérateurs
    Observable.from(1, 2, 3, 4)
    .filter((i) -> (i % 2) == 0)
    .subscribe(System.out::println)
    

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43. Opérateurs
    Observable.from(1, 2, 3, 4)
    .filter((i) -> (i % 2) == 0)
    .subscribe(System.out::println)
    

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44. Opérateurs
    Observable.from(1, 2, 3, 4)
    .filter((i) -> (i % 2) == 0)
    .subscribe(System.out::println)
    2
    

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45. Opérateurs
    Observable.from(1, 2, 3, 4)
    .filter((i) -> (i % 2) == 0)
    .subscribe(System.out::println)
    2
    4
    

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46. Opérateurs
    Observable.from(1, 2, 3, 4)
    .take(2)
    .subscribe(System.out::println);
    

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47. Opérateurs
    Observable.from(1, 2, 3, 4)
    .take(2)
    .subscribe(System.out::println);
    1
    2
    

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48. Opérateurs
    Observable.from(1, 2, 3, 4)
    .map((i) -> i * 10)
    .subscribe(System.out::println);
    

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49. Opérateurs
    Observable.from(1, 2, 3, 4)
    .map((i) -> i * 10)
    .subscribe(System.out::println);
    10
    20
    30
    40
    

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50. Composition
    

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51. Composition
    

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52. Composition
    

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53. Composition
    couleurs
    formes
    

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54. Programmation synchrone
    observableReadingSynchronously(“strings.txt”)
    .take(10)
    .delay(1, SECONDS)
    .map(parse())
    .map(n -> “=> ” + n))
    .subscribe(to_the_view())
    

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55. Programmation synchrone
    main
    

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56. Programmation synchrone
    observableReadingSynchronously(“strings.txt”)
    .take(10)
    .delay(1, SECONDS)
    .map(parse())
    .map(n -> “=> ” + n))
    .subscribe(to_the_view())
    

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57. Programmation asynchrone
    Computation
    IO
    UI
    main
    source
    

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58. Programmation asynchrone
    Computation
    IO
    UI
    main
    source
    ...
    .subscribeOn(Schedulers.io())
    

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59. Programmation asynchrone
    Computation
    IO
    UI
    main
    source
    .take(...)
    .subscribeOn(Schedulers.io())
    

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60. Programmation asynchrone
    Computation
    IO
    UI
    main
    .delay(..., Schedulers.computation())
    

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61. Programmation asynchrone
    Computation
    IO
    UI
    main
    .delay(..., Schedulers.computation())
    .map(...)
    

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62. Programmation asynchrone
    Computation
    IO
    UI
    main
    .observeOn(Schedulers.from(...))
    .map(...)
    

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63. Programmation asynchrone
    Computation
    IO
    UI
    main
    .observeOn(Schedulers.from(...))
    .map(...)
    .subscribe(...)
    

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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())
    

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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())
    

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66. Aller plus loin
    Séquence
    finie & infinie
    Unsubscribe
    BackPressure
    Reactive Streams
    Hot & Cold
    observable
    

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67. Aller plus loin
    Séquence
    finie & infinie
    Unsubscribe
    BackPressure
    Reactive Streams
    Hot & Cold
    observable
    

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68. Aller plus loin
    Séquence
    finie & infinie
    Unsubscribe
    BackPressure
    Reactive Streams
    Hot & Cold
    observable
    

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69. Aller plus loin
    Séquence
    finie & infinie
    Unsubscribe
    BackPressure
    Reactive Streams
    Hot & Cold
    observable
    

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70. Aller plus loin
    Séquence
    finie & infinie
    Unsubscribe
    BackPressure
    Reactive Streams
    Hot & Cold
    observable
    

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71. Aller plus loin
    Séquence
    finie & infinie
    Unsubscribe
    BackPressure
    Reactive Streams
    Hot & Cold
    observable
    

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72. Questions ?
    

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