RxJava, RxJava 2, Reactor: State of the art of Reactive Streams on the JVM

RxJava is used on Android or in backend side thanks to Hystrix. RxJava 2 is now available and will be able to use the path build by the previous version. Pivotal promote Reactor that will be available in Spring Boot 2.

What is the differences between each of these implementations of the Reactive Streams? Why chose RxJava 2 over Reactor or over RxJava?

This conference talk will focus on the history of each implementation then will compare APIs, performances and use cases of these Reactive Streams.

- DevDays Vilinus - may 2018

Transcript

1. Got a question
   during this session? 

   Post it on sli.do
   ( #K100 )
   

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2. RxJava, RxJava 2, Reactor
   State of the art of Reactive Streams on the JVM
   

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3. David
   Wursteisen
   

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4. View Slide

5. Writing asynchronous code: 

   it sucks
   

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6. Future
   ExecutorService ex = Executors.newCachedThreadPool();

   Future future = ex.submit(() -> longProcessing());

   String result = future.get();
   Blocking call
   

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7. Future
   Future> future1 = /* ... */

   Future> future2 = /* ... */

   Future> future3 = /* ... */

   Future> future4 = /* ... */

   Future> future5 = /* ... */
   Optimal
   Orchestration ?
   

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8. Callback
   RemoteService service = buildRemoteService();

   service.getUser(id -> {

   service.getData(id, data -> {

   service.getSomething(data, whut -> {
   service.neverEndingCallBack(whut, () -> {
   });
   });

   });

   });
   Callback Hell
   

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9. Relationship Status:

   it’s complicated
   

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10. The problem
    of synchronous code
    

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11. Synchronous
    Waiting for the
    response
    Caller
    Called
    

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12. Impact on
    response time
    Slow server
    

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13. It never works!
    It piss me off!
    

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14. Asynchronous
    Caller
    Called
    Continuous work
    

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15. Asynchronous allow to take advantage of
    the waiting time
    

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16. Minimal impact
    on the response
    time
    

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17. Write asynchronous code
    easily?
    

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18. Emergence 

    of different approaches
    

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19. 2
    Reactive Streams
    

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20. Reactive Streams
    Reactive Streams API
    RxJava 2 Reactor
    Interface
    Implementation
    

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21. Reactive Streams API is 

    a bridge 

    between implementations
    

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22. Reactive Streams contract
    onSubscribe onNext onError
    onComplete
    

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23. RxJava is
    not compatible 

    with Reactive Streams
    (You’ll have to use an adapter: RxJavaReactiveStreams)
    https://github.com/ReactiveX/RxJavaReactiveStreams
    

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24. onNext * ( onError | onComplete )
    

    onNext * ( onError | onCompleted )
    RxJava
    Reactive Streams
    

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25. onNext * ( onError | onComplete )
    

    onNext * ( onError | onCompleted )
    RxJava
    Reactive Streams
    Different name
    

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26. Common
    approach
    

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27. A P I t o h a n d l e e v e n t s
    synchronously or asynchronously
    through a flow of events
    

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28. View Slide

29. Map ( ⃝ →
    ⬛)
    

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30. View Slide

31. remoteApi.people(1).flatMap(luke -> {
    

    Observable vehicles = Observable.from(luke.getVehiclesIds())

    .flatMap(remoteApi::vehicle)

    .map(vehicle -> luke.getName() + " can drive " + vehicle.getName());

    

    Observable starships = Observable.from(luke.getStarshipsIds())

    .flatMap(remoteApi::starship)

    .map(starship -> luke.getName() + " can fly with " + starship.getName());

    

    return Observable.merge(vehicles, starships);
    

    }).subscribe(System.out::println);
    

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32. remoteApi.people(1).flatMap(luke -> {
    

    Observable vehicles = Observable.from(luke.getVehiclesIds())

    .flatMap(remoteApi::vehicle)

    .map(vehicle -> luke.getName() + " can drive " + vehicle.getName());

    

    Observable starships = Observable.from(luke.getStarshipsIds())

    .flatMap(remoteApi::starship)

    .map(starship -> luke.getName() + " can fly with " + starship.getName());

    

    return Observable.merge(vehicles, starships);
    

    }).subscribe(System.out::println);
    Push of the result
    

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33. remoteApi.people(1).flatMap(luke -> {
    

    Observable vehicles = Observable.from(luke.getVehiclesIds())

    .flatMap(remoteApi::vehicle)

    .map(vehicle -> luke.getName() + " can drive " + vehicle.getName());

    

    Observable starships = Observable.from(luke.getStarshipsIds())

    .flatMap(remoteApi::starship)

    .map(starship -> luke.getName() + " can fly with " + starship.getName());

    

    return Observable.merge(vehicles, starships);
    

    }).subscribe(System.out::println);
    Get Luke’s vehicles
    Get Luke’s starships
    

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34. remoteApi.people(1).flatMap(luke -> {
    

    Observable vehicles = Observable.from(luke.getVehiclesIds())

    .flatMap(remoteApi::vehicle)

    .map(vehicle -> luke.getName() + " can drive " + vehicle.getName());

    

    Observable starships = Observable.from(luke.getStarshipsIds())

    .flatMap(remoteApi::starship)

    .map(starship -> luke.getName() + " can fly with " + starship.getName());

    

    return Observable.merge(vehicles, starships);
    

    }).subscribe(System.out::println);
    Merge of two flows
    

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35. remoteApi.people(1).flatMap(luke -> {
    

    Observable vehicles = Observable.from(luke.getVehiclesIds())

    .flatMap(remoteApi::vehicle)

    .map(vehicle -> luke.getName() + " can drive " + vehicle.getName());

    

    Observable starships = Observable.from(luke.getStarshipsIds())

    .flatMap(remoteApi::starship)

    .map(starship -> luke.getName() + " can fly with " + starship.getName());

    

    return Observable.merge(vehicles, starships);
    

    }).subscribe(System.out::println);
    Really execute the code
    

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36. remoteApi.people(1).flatMap(luke -> {
    

    Observable vehicles = Observable.from(luke.getVehiclesIds())

    .flatMap(remoteApi::vehicle)

    .map(vehicle -> luke.getName() + " can drive " + vehicle.getName());

    

    Observable starships = Observable.from(luke.getStarshipsIds())

    .flatMap(remoteApi::starship)

    .map(starship -> luke.getName() + " can fly with " + starship.getName());

    

    return Observable.merge(vehicles, starships);
    

    }).subscribe(System.out::println);
    Flow of events
    

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37. remoteApi.people(1).flatMap(luke -> {
    

    Observable vehicles = Observable.from(luke.getVehiclesIds())

    .flatMap(remoteApi::vehicle)

    .map(vehicle -> luke.getName() + " can drive " + vehicle.getName());

    

    Observable starships = Observable.from(luke.getStarshipsIds())

    .flatMap(remoteApi::starship)

    .map(starship -> luke.getName() + " can fly with " + starship.getName());

    

    return Observable.merge(vehicles, starships);
    

    }).subscribe(System.out::println);
    Flow of events
    Flow of events
    

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38. View Slide

39. Button btn = new Button();

    btn.setText("Click Me");

    

    JavaFx.fromClick(btn) 

    .observeOn(Schedulers.io()) 

    .switchMap(evt -> remoteApi.getData())

    .observeOn(javaFx()) 

    .doOnNext(value -> btn.setText("Data: " + value))

    .subscribe();
    

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40. Button btn = new Button();

    btn.setText("Click Me");

    

    JavaFx.fromClick(btn) // Observable

    .observeOn(Schedulers.io())

    .switchMap(evt -> remoteApi.getData())

    .observeOn(javaFx()) 

    .doOnNext(value -> btn.setText("Data: " + value))

    .subscribe();
    Listen for clicks
    

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41. Button btn = new Button();

    btn.setText("Click Me");

    

    JavaFx.fromClick(btn) // Observable

    .observeOn(Schedulers.io())

    .switchMap(evt -> remoteApi.getData())

    .observeOn(javaFx()) 

    .doOnNext(value -> btn.setText("Data: " + value))

    .subscribe();
    Execution context
    switch
    

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42. Button btn = new Button();

    btn.setText("Click Me");

    

    JavaFx.fromClick(btn) // Observable

    .observeOn(Schedulers.io())

    .switchMap(evt -> remoteApi.getData()) // Observable

    .observeOn(javaFx()) 

    .doOnNext(value -> btn.setText("Data: " + value))

    .subscribe();
    Asynchronous call to
    a web service
    

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43. Button btn = new Button();

    btn.setText("Click Me");

    

    JavaFx.fromClick(btn) // Observable

    .observeOn(Schedulers.io())

    .switchMap(evt -> remoteApi.getData()) // Observable

    .observeOn(javaFx()) 

    .doOnNext(value -> btn.setText("Data: " + value))

    .subscribe();
    Execution context
    switch
    

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44. Button btn = new Button();

    btn.setText("Click Me");

    

    JavaFx.fromClick(btn) // Observable

    .observeOn(Schedulers.io())

    .switchMap(evt -> remoteApi.getData()) // Observable

    .observeOn(javaFx()) 

    .doOnNext(value -> btn.setText("Data: " + value))

    .subscribe();
    Update on the UI
    

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45. Button btn = new Button();

    btn.setText("Click Me");

    

    JavaFx.fromClick(btn) // Observable

    .observeOn(Schedulers.io())

    .switchMap(evt -> remoteApi.getData()) // Observable

    .observeOn(javaFx()) 

    .doOnNext(value -> btn.setText("Data: " + value))

    .subscribe();
    Flow of events
    

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46. Thanks to RxJava
    and Reactor
    …
    

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47. Writing asynchronous code: 

    it sucks
    

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48. Once upon a time…
    

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49. Creation of 

    Reactive Extensions
    Creation of RxJava
    Active Participation
    Resumption of 

    RxJava & RxJava 2
    Creation of Reactor
    Work on Reactor
    

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50. RxJava 

    is a 

    proved

    technologie
    

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51. Reactor

    benefits from the experience of

    RxJava
    (and vice versa)
    

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52. Object types
    

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53. Observable
    

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54. View Slide

55. View Slide

56. View Slide

57. View Slide

58. View Slide

59. Single
    

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60. View Slide

61. Completable
    

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62. View Slide

63. RxJava
    Contrat Backpressure
    Observable [N] Yes
    Single [1] No
    Completable [0] No
    Added afterward
    Web service
    call
    Background
    process
    

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64. Listen a websocket, for each
    received command, compose a
    response by calling 3 different
    webservices, then execute 2 jobs
    sequentially ?
    

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65. Listen a websocket, for each
    received command, compose a
    response by calling 3 different
    webservices, then execute 2 jobs
    sequentially ?
    

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66. Listen a websocket, for each
    received command, compose a
    response by calling 3 different
    webservices, then execute 2 jobs
    sequentially ?
    

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67. Listen a websocket, for each
    received command, compose a
    response by calling 3 different
    webservices, then execute 2 jobs
    sequentially ?
    

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68. websocket("/topics/cmd")

    .observeOn(Schedulers.io())

    .switchMap(cmd ->

    Single.zip(

    api.getActions(),

    api.getScore(),

    api.getUserData(),

    this::composeResult).toObservable())

    .observeOn(Schedulers.computation())

    .concatMap(result -> updateDb(result).andThen(getLastResults()))

    .subscribe(last -> System.out.println("last results -> " + last));
    

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69. websocket("/topics/cmd")

    .observeOn(Schedulers.io())

    .switchMap(cmd ->

    Single.zip(

    api.getActions(),

    api.getScore(),

    api.getUserData(),

    this::composeResult).toObservable())

    .observeOn(Schedulers.computation())

    .concatMap(result -> updateDb(result).andThen(getLastResults()))

    .subscribe(last -> System.out.println("last results -> " + last));
    Listen a websocket
    Observable
    

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70. websocket("/topics/cmd")

    .observeOn(Schedulers.io())

    .switchMap(cmd ->

    Single.zip(

    api.getActions(),

    api.getScore(),

    api.getUserData(),

    this::composeResult).toObservable())

    .observeOn(Schedulers.computation())

    .concatMap(result -> updateDb(result).andThen(getLastResults()))

    .subscribe(last -> System.out.println("last results -> " + last));
    Webservices composition
    Single
    

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71. websocket("/topics/cmd")

    .observeOn(Schedulers.io())

    .switchMap(cmd ->

    Single.zip(

    api.getActions(),

    api.getScore(),

    api.getUserData(),

    this::composeResult).toObservable())

    .observeOn(Schedulers.computation())

    .concatMap(result -> updateDb(result).andThen(getLastResults()))

    .subscribe(last -> System.out.println("last results -> " + last));
    Completable
    2 jobs executions
    

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72. websocket("/topics/cmd")

    .observeOn(Schedulers.io())

    .switchMap(cmd ->

    Single.zip(

    api.getActions(),

    api.getScore(),

    api.getUserData(),

    this::composeResult).toObservable())

    .observeOn(Schedulers.computation())

    .concatMap(result -> updateDb(result).andThen(getLastResults()))

    .subscribe(last -> System.out.println("last results -> " + last));
    Listen a websocket
    Observable Webservices composition
    Single
    Completable
    2 jobs executions
    

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73. RxJava 2
    Contrat Backpressure
    Observable [N] No
    Single [1] No
    Completable [0] No
    Maybe [0|1] No New!
    Close to Java 8
    Optional
    

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74. Maybe
    

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75. View Slide

76. Backpressure
    using RxJava 2
    

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77. Consumer
    

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78. Consumer
    To many things !
    

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79. backpressure
    

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80. MissingBackpressureException ?
    

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81. acceptedIntent

    .filter(intent -> !intent.getBooleanExtra("UpdatePhoneMode", false))

    .concatMap(intent -> approximatedEngine.detectCurrentPlace())

    .doOnNext(score -> Log.info(TAG, "Scan completed with result " + score))

    .concatMap(this::detectSleepMode)

    .concatMap((score) -> isNewPlace(score.getScore().getPlace()).map(p -> score))

    .doOnNext((p) -> Log.info(TAG, "Current place found is : " + p))

    .subscribe()
    

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82. acceptedIntent

    .filter(intent -> !intent.getBooleanExtra("UpdatePhoneMode", false))
    .onBackpressureDrop()

    .concatMap(intent -> approximatedEngine.detectCurrentPlace())

    .doOnNext(score -> Log.info(TAG, "Scan completed with result " + score))

    .onBackpressureDrop()
    .concatMap(this::detectSleepMode)

    .onBackpressureDrop()

    .concatMap((score) -> isNewPlace(score.getScore().getPlace()).map(p -> score))

    .doOnNext((p) -> Log.info(TAG, "Current place found is : " + p))

    .subscribe()
    Added while I
    panicked
    

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83. RxJava 2
    Contrat Backpressure
    Observable [N] No
    Single [1] No
    Completable [0] No
    Maybe [0|1] No New!
    Close to Java 8
    Optional
    

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84. RxJava 2
    Contrat Backpressure
    Observable [N] No
    Single [1] No
    Completable [0] No
    Maybe [0|1] No
    Flowable [N] Yes
    New!
    Observable with 

    back pressure
    Close to Java 8
    Optional
    

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85. Observable
    → less than 1000 events
    → User interface management
    → To be used instead of Java 8 Streams
    Flowable
    → more than 10 000 events
    → Control the data flow
    → Network stream with flow management
    

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86. What does Reactor offer ?
    

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87. Flux
    Mono
    Maximum of 1
    element
    

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88. Reactor
    Contrat Backpressure
    Flux [N] Yes
    Mono [0|1] Yes
    Identical to
    Flowable
    Flux with only 

    1 element
    

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89. Object types and

    Reactive Streams
    

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90. Publisher
    Flux Flowable
    Reactive Streams
    

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91. Flux.range(1, 10)

    .flatMap(i -> Flux.just(1))

    .subscribe();
    

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92. Flux.range(1, 10)

    .flatMap(i -> Flux.just(1))

    .subscribe();
    Publisher
    

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93. Flux.range(1, 10)

    .flatMap(i -> Flowable.just(1))

    .subscribe();
    Publisher
    RxJava 2
    

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94. Flowable.defer(() -> Flux.range(1, 10))

    .subscribe(System.out::println);
    RxJava 2 Reactor
    

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95. Flux.defer(() -> Flowable.range(1, 10))

    .subscribe(System.out::println);
    RxJava 2
    Reactor
    

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96. You can use a library
    which use RxJava 2 in
    your Reactor project
    (and vice versa)
    

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97. Operators
    

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98. Consequent and homogenous
    Catalogue
    

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99. all amb ambArray ambWith any as awaitOnSubscribe blockFirst blockFirstMillis blockLast blockLastMillis
    blockingFirst blockingForEach blockingIterable blockingLast blockingLatest blockingMostRecent blockingNext
    blockingSingle blockingSubscribe buffer bufferMillis bufferSize bufferTimeout bufferTimeoutMillis bufferUntil
    bufferWhile cache cacheWithInitialCapacity cancelOn cast checkpoint collect collectInto collectList collectMap
    collectMultimap collectSortedList combineLatest combineLatestDelayError compose concat concatArray
    concatArrayDelayError concatArrayEager concatDelayError concatEager concatMap concatMapDelayError
    concatMapEager concatMapEagerDelayError concatMapIterable concatWith contains count create debounce
    defaultIfEmpty defer delay delayElements delayElementsMillis delayMillis delaySubscription delaySubscriptionMillis
    dematerialize distinct distinctUntilChanged doAfterNext doAfterTerminate doFinally doOnCancel doOnComplete
    doOnEach doOnError doOnLifecycle doOnNext doOnRequest doOnSubscribe doOnTerminate elapsed elementAt
    elementAtOrError empty equals error filter first firstElement firstEmitting firstEmittingWith firstOrError flatMap
    flatMapCompletable flatMapIterable flatMapMaybe flatMapSequential flatMapSingle forEach forEachWhile from
    fromArray fromCallable fromFuture fromIterable fromPublisher fromStream generate getClass getPrefetch groupBy
    groupJoin handle hasElement hasElements hashCode hide ignoreElements interval intervalMillis intervalRange
    isEmpty join just last lastElement lastOrError lift limitRate log map mapError materialize merge mergeArray
    mergeArrayDelayError mergeDelayError mergeSequential mergeWith never next notify notifyAll observeOn ofType
    onBackpressureBuffer onBackpressureDrop onBackpressureError onBackpressureLatest onErrorResumeNext
    onErrorResumeWith onErrorReturn onErrorReturnItem onExceptionResumeNext onTerminateDetach parallel publish
    publishNext publishOn range rangeLong rebatchRequests reduce reduceWith repeat repeatUntil repeatWhen
    replay replayMillis retry retryUntil retryWhen safeSubscribe sample sampleFirst sampleFirstMillis sampleMillis
    sampleTimeout scan scanWith sequenceEqual serialize share single singleElement singleOrEmpty singleOrError
    skip skipLast skipMillis skipUntil skipUntilOther skipWhile sort sorted startWith startWithArray strict subscribe
    subscribeOn subscribeWith switchIfEmpty switchMap switchMapDelayError switchOnError switchOnNext
    switchOnNextDelayError take takeLast takeMillis takeUntil takeUntilOther takeWhile test then thenEmpty thenMany
    throttleFirst throttleLast throttleWithTimeout timeInterval timeout timeoutMillis timer timestamp to toFuture toIterable
    toList toMap toMultimap toObservable toSortedList toStream toString transform unsafeCreate unsubscribeOn using
    wait window windowMillis windowTimeout windowTimeoutMillis windowUntil windowWhile withLatestFrom zip
    zipArray zipIterable zipWith zipWithIterable
    

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100. RxJava RxJava 2 Reactor
     flatMap flatMap flatMap
     Emit Noe, one or
     more events
     amb amb firstEmitting
     Emit events from the
     first emitting stream
     … … … …
     debounce debounce N/A
     Ignore events during
     a time laps
     

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101. RxJava RxJava 2 Reactor
     flatMap flatMap flatMap
     Emit Noe, one or
     more events
     amb amb firstEmitting
     Emit events from the
     first emitting stream
     … … … …
     debounce debounce N/A
     Ignore events during
     a time laps
     Renamed
     

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102. Operators
     cover
     a lot of scenarios
     

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103. Nota bene
     

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104. https://github.com/ReactiveX/RxJava/wiki/Implementing-custom-operators-(draft)
     writing operators is hard
     when one writes an operator, the Observable
     protocol, unsubscription, backpressure and
     concurrency have to be taken into account and
     adhered to the letter
     

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105. Writing a new operator with RxJava 2
     is more complex
     than with RxJava
     

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106. Make a application
     Reactive
     

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107. Reactive
     Reactive
     Synchronous API
     Callback
     Reactive
     Reactive
     

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108. Factory
     

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109. RxJava

     RxJava 2
     Reactor
     Flowable.just Flux.just Emitting existing value
     Flowable.defer Flux.defer Lazy emitting
     Flowable.fromCallable Mono.fromCallable
     Lazy emitting, computed from
     a method call
     Flowable.create Flux.create Manual emitting
     Flowable.using Flux.using Resource management
     Flowable.fromPublisher Flux.from
     Using a Publisher (Reactive
     Streams)
     Flowable.generate Flux.generate Using a value generator
     

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110. RxJava

     RxJava 2
     Reactor
     Flowable.just Flux.just Emitting existing value
     Flowable.defer Flux.defer Lazy emitting
     Flowable.fromCallable Mono.fromCallable
     Lazy emitting, computed from
     a method call
     Flowable.create Flux.create Manual emitting
     Flowable.using Flux.using Resource management
     Flowable.fromPublisher Flux.from
     Using a Publisher (Reactive
     Streams)
     Flowable.generate Flux.generate Using a value generator
     

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111. RxJava

     RxJava 2
     Reactor
     Flowable.just Flux.just Emitting existing value
     Flowable.defer Flux.defer Lazy emitting
     Flowable.fromCallable Mono.fromCallable
     Lazy emitting, computed from
     a method call
     Flowable.create Flux.create Manual emitting
     Flowable.using Flux.using Resource management
     Flowable.fromPublisher Flux.from
     Using a Publisher (Reactive
     Streams)
     Flowable.generate Flux.generate Using a value generator
     

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112. RxJava

     RxJava 2
     Reactor
     Flowable.just Flux.just Emitting existing value
     Flowable.defer Flux.defer Lazy emitting
     Flowable.fromCallable Mono.fromCallable
     Lazy emitting, computed from
     a method call
     Flowable.create Flux.create Manual emitting
     Flowable.using Flux.using Resource management
     Flowable.fromPublisher Flux.from
     Using a Publisher (Reactive
     Streams)
     Flowable.generate Flux.generate Using a value generator
     

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113. example of
     wrapping
     

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114. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis")

     private String redis() throws InterruptedException {

     CountDownLatch latch = new CountDownLatch(1);

     AtomicReference result = new AtomicReference<>();

     this.connection.subscribe((message, pattern) -> {

     result.set(message.toString());

     latch.countDown();

     }, TOPIC_NAME);

     latch.await();

     return result.get();

     }
     }
     

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115. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis")

     private String redis() throws InterruptedException {

     CountDownLatch latch = new CountDownLatch(1);

     AtomicReference result = new AtomicReference<>();

     this.connection.subscribe((message, pattern) -> {

     result.set(message.toString());

     latch.countDown();

     }, TOPIC_NAME);

     latch.await();

     return result.get();

     }
     }
     

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116. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis")

     private String redis() throws InterruptedException {

     CountDownLatch latch = new CountDownLatch(1);

     AtomicReference result = new AtomicReference<>();

     this.connection.subscribe((message, pattern) -> {

     result.set(message.toString());

     latch.countDown();

     }, TOPIC_NAME);

     latch.await();

     return result.get();

     }
     }
     

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117. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis")

     private String redis() throws InterruptedException {

     CountDownLatch latch = new CountDownLatch(1);

     AtomicReference result = new AtomicReference<>();

     this.connection.subscribe((message, pattern) -> {

     result.set(message.toString());

     latch.countDown();

     }, TOPIC_NAME);

     latch.await();

     return result.get();

     }
     }
     Code for synchronisation
     Code for synchronisation
     

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118. Step 1 

     Wrapping
     

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119. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis")

     private String redis() throws InterruptedException {

     

     String result = Flowable.create(sub -> {

     this.connection.subscribe((message, pattern) -> {

     sub.onNext(message.toString());

     sub.onComplete();

     }, TOPIC_NAME);

     }, BackpressureStrategy.BUFFER)

     .blockingFirst();

     return result;

     }
     }
     

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120. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis")

     private String redis() throws InterruptedException {

     

     String result = Flowable.create(sub -> {

     this.connection.subscribe((message, pattern) -> {

     sub.onNext(message.toString());

     sub.onComplete();

     }, TOPIC_NAME);

     }, BackpressureStrategy.BUFFER)

     .blockingFirst();

     return result;

     }
     }
     Wrapping
     Synchronisation
     Reactive Contract
     

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121. Step 2
     Asynchronous
     

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122. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis")

     private DeferredResult redis() throws InterruptedException {

     

     DeferredResult result = new DeferredResult<>(10_000l);

     

     Flowable.create(sub -> {

     this.connection.subscribe((message, pattern) -> {

     sub.onNext(message.toString());

     sub.onComplete();

     }, TOPIC_NAME);

     }, BackpressureStrategy.BUFFER)

     .subscribe(result::setResult);

     

     return result;

     }
     

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123. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis")

     private DeferredResult redis() throws InterruptedException {

     

     DeferredResult result = new DeferredResult<>(10_000l);

     

     Flowable.create(sub -> {

     this.connection.subscribe((message, pattern) -> {

     sub.onNext(message.toString());

     sub.onComplete();

     }, TOPIC_NAME);

     }, BackpressureStrategy.BUFFER)

     .subscribe(result::setResult);

     

     return result;

     } Lazy result
     Use of DeferredResult
     

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124. Step 3 

     Reactive Streams
     

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125. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis", produces = MediaType.TEXT_EVENT_STREAM_VALUE)

     private Flux redis() throws InterruptedException {

     

     Flowable rxjava = Flowable.create(sub -> {

     this.connection.subscribe((message, pattern) -> sub.onNext(message.toString()),
     TOPIC_NAME);

     }, BackpressureStrategy.BUFFER);

     

     return Flux.defer(() -> rxjava);

     }
     }
     

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126. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis", produces = MediaType.TEXT_EVENT_STREAM_VALUE)

     private Flux redis() throws InterruptedException {

     

     Flowable rxjava = Flowable.create(sub -> {

     this.connection.subscribe((message, pattern) -> sub.onNext(message.toString()),
     TOPIC_NAME);

     }, BackpressureStrategy.BUFFER);

     

     return Flux.defer(() -> rxjava);

     }
     }
     RxJava 2 → Flux
     Flux → SSE
     Return a Flux
     

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127. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis", produces = MediaType.TEXT_EVENT_STREAM_VALUE)

     private Publisher redis() throws InterruptedException {

     return Flowable.create(sub -> {

     this.connection.subscribe((message, pattern) -> sub.onNext(message.toString()),
     TOPIC_NAME);

     }, BackpressureStrategy.BUFFER);

     

     }
     

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128. @RestController

     public class HelloController {

     

     private static final byte[] TOPIC_NAME = "topic".getBytes();

     

     @RequestMapping(value = "/redis", produces = MediaType.TEXT_EVENT_STREAM_VALUE)

     private Publisher redis() throws InterruptedException {

     return Flowable.create(sub -> {

     this.connection.subscribe((message, pattern) -> sub.onNext(message.toString()),
     TOPIC_NAME);

     }, BackpressureStrategy.BUFFER);

     

     }
     Publisher
     

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129. View Slide

130. Reactor use Java 8
     while RxJava 2 use
     Java 6
     

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131. Reactor use Java 8
     while RxJava 2 use
     Java 6
     

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132. Asynchronous
     Execution context management
     

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133. Schedulers
     Rethink cette partie là
     

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134. Scheduler 

     (Thread Pool)
     Task 1
     Task 2
     Task 3
     Task 4
     

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135. Task 1
     Task 2
     Task 3
     Task 4
     Scheduler 

     (Thread Pool)
     

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136. Task 1 Task 2
     Task 3
     Task 4
     Scheduler 

     (Thread Pool)
     

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137. Task 1 Task 2
     Task 3
     Task 4
     Scheduler 

     (Thread Pool)
     

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138. Task 1 Task 2
     Task 3 Task 4
     Scheduler 

     (Thread Pool)
     

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139. Task 1
     Task 2
     Task 3 Task 4
     Scheduler 

     (Thread Pool)
     

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140. Task 1
     Task 2
     Task 3
     Task 4
     Scheduler 

     (Thread Pool)
     

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141. Task 1
     Task 2
     Task 3
     Task 4
     Scheduler 

     (Thread Pool)
     

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142. Task 1
     Task 2
     Task 3
     Task 4
     Scheduler 

     (Thread Pool)
     

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143. java.lang.IllegalStateException: 

     Not on the main thread
     NetworkOnMainThreadException
     

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144. JavaFx.fromClick(btn) 

     .observeOn(Schedulers.io())

     .switchMap(evt -> remoteApi.getData())

     .observeOn(Schedulers.computation())

     .flatMap(data -> intensiveComputation(data))

     .observeOn(javaFx())

     .doOnNext(value -> btn.setText("Data: " + value)) 

     .subscribe();
     

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145. JavaFx.fromClick(btn) 

     .observeOn(Schedulers.io())

     .switchMap(evt -> remoteApi.getData())

     .observeOn(Schedulers.computation())

     .flatMap(data -> intensiveComputation(data))

     .observeOn(javaFx())

     .doOnNext(value -> btn.setText("Data: " + value)) 

     .subscribe();
     i/o
     computation
     UI Thread
     

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146. RxJava RxJava 2 Reactor Description
     io() io() elastic()
     Thread pool which
     grow up if needed
     computation() computation() parallel() Limited thread pool
     single() single() single() Pool of 1 thread
     immediate() immediate()
     Execute the task
     immediately
     trampoline() trampoline()
     Queue the current
     task
     

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147. RxJava RxJava 2 Reactor Description
     io() io() elastic()
     Thread pool which
     grow up if needed
     computation() computation() parallel() Limited thread pool
     single() single() single() Pool of 1 thread
     immediate() immediate()
     Execute the task
     immediately
     trampoline() trampoline()
     Queue the current
     task
     

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148. RxJava RxJava 2 Reactor Description
     io() io() elastic()
     Thread pool which
     grow up if needed
     computation() computation() parallel() Limited thread pool
     single() single() single() Pool of 1 thread
     immediate() immediate()
     Execute the task
     immediately
     trampoline() trampoline()
     Queue the current
     task
     

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149. Reactor
     Technical naming
     

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150. RxJava
     Functional naming
     

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151. Performance
     

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152. Generation
     3 4 5+
     Fusion
     RxJava 2
     Reactor
     

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153. Warning
     Conceptuel slides
     

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154. Without fusion
     

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155. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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156. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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157. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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158. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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159. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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160. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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161. With fusion
     

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162. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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163. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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164. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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165. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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166. Transform (
     ⬛ → ⃝ )
     Transform ( ⃝ →
     ⬛)
     

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167. Fusion
     decreases
     memory consumption and
     increases
     performances
     

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168. for (int x = 0; x < 10_000; x++) {

     

     Observable.interval(10, TimeUnit.MILLISECONDS)

     .takeWhile(i -> take.get())

     .flatMap(i -> Observable.range(1, 100))

     .subscribe();

     }
     

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169. RxJava 2 RxJava
     Reactor
     

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170. http://akarnokd.blogspot.fr/2016/12/the-reactive-scrabble-benchmarks.html
     Java 8 Stream
     RxJava 2 / Reactor
     RxJava
     December 2016
     

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171. Java 8 Stream
     RxJava 2 / Reactor
     RxJava
     https://twitter.com/akarnokd/status/844555409012740096
     March 2017
     

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172. Ecosystem
     

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173. RxJava RxJava 2 Reactor
     Retrofit Yes Yes No
     RxAndroid Yes Yes No
     Realm Yes No No
     Hystrix Yes No No
     Couchbase Yes No No
     MongoDB Yes No No
     Spring Data 2.0 Yes No Yes
     Reactor IPC No No Yes
     WebFlux No Yes Yes
     Android Spring
     

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174. RxJava RxJava 2 Reactor
     Retrofit Yes Yes No
     RxAndroid Yes Yes No
     Realm Yes No No
     Hystrix Yes No No
     Couchbase Yes No No
     MongoDB Yes No No
     Spring Data 2.0 Yes No Yes
     Reactor IPC No No Yes
     WebFlux No Yes Yes
     Android Spring
     

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175. We are aggressively 

     migrating our internal code to
     RxJava 2
     https://github.com/uber/AutoDispose
     

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176. RxJava RxJava 2 Reactor
     Retrofit Yes Yes No
     RxAndroid Yes Yes No
     Realm Yes No No
     Hystrix Yes No No
     Couchbase Yes No No
     MongoDB Yes No No
     Spring Data 2.0 Yes No Yes
     Reactor IPC No No Yes
     WebFlux No Yes Yes
     Android Spring
     

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177. Inertia
     to migrate
     

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178. RxJava RxJava 2 Reactor
     Retrofit Yes Yes No
     RxAndroid Yes Yes No
     Realm Yes No No
     Hystrix Yes No No
     Couchbase Yes No No
     MongoDB Yes No No
     Spring Data 2.0 Yes No Yes
     Reactor IPC No No Yes
     WebFlux No Yes Yes
     Android Spring
     

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179. Spring 5 will accelerate
     the adoption of Reactor
     

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180. Android
     RxJava 2
     

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181. Backend
     RxJava 2
     

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182. Spring
     Reactor
     

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183. Thanks for your attention
     We stay in touch?
     david.wursteisen@soat.fr
     @dwursteisen
     http://blog.soat.fr
     Post your question on sli.do
     ( #K100 )
     

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