Reactive Spring

Reactive Spring

This workshop explains reactive programming concepts, using Project Reactor and Spring to build asynchronous, non-blocking applications.

Code: https://github.com/mp911de/reactive-spring

C5f6e8dffbb19acf405198c8fb917337?s=128

Mark Paluch

May 08, 2017
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  1. Unless otherwise indicated, these slides are © 2013-2014 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive Spring JAX 2017 Mark Paluch, Pivotal Software, Inc. @mp911de
  2. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ @mp911de github.com/mp911de paluch.biz Mark Paluch
  3. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ What is Reactive Programming?
  4. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Imperative ! Reactive ! Synchronous ! Blocking ! Non-Blocking ! Asynchronous ! Actors 4 Programming models
  5. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 5 Understanding imperative HttpClient c = …; HttpGet get = new HttpGet("https://google.com"); HttpResponse response = c.execute(get);
  6. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 6 Understanding imperative EntityManager entityManager = …; List<User> users = … entityManager.getTransaction().begin(); for (User user : users) { entityManager.persist(user); } entityManager.getTransaction().commit();
  7. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 7 Understanding imperative public void saveUsers() { EntityManager entityManager = …; List<User> users = … entityManager.getTransaction().begin(); for (User user : users) { entityManager.persist(user); } entityManager.getTransaction().commit(); }
  8. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 8 Understanding imperative HttpClient c = …; for (int i = 0; i < 10; i++) { HttpGet get = new HttpGet("https://google.com"); HttpResponse response = c.execute(get); // … }
  9. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Remote calls with latency 9 Request Data access Remote data service
  10. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Remote calls with latency 9 Request Data access Remote data service
  11. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Remote calls with latency 9 Request Data access Remote data service I/O Wait
  12. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Remote calls with latency 9 Request Data access Remote data service I/O Wait
  13. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Remote calls with latency 9 Request Data access Remote data service I/O Wait This one is waiting
  14. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Remote calls with latency 9 Request Data access Remote data service I/O Wait This one is waiting
  15. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Makes assumptions over resource usage ! Developers are in charge of resource usage efficiency 10 Imperative programming
  16. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Container calls code on a Thread ! Call continues until all work is done ! Thread is occupied ! Thread is released at the end of work • Latencies affect duration in which Thread is occupied 11 Imperative: Web applications
  17. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Reactive is used to describe event-driven systems ! Reactive is used more for scalability and stability than for speed ! Reacts to resource availability 12 What is reactive?
  18. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Synchronous fetch model 13
  19. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Synchronous fetch model 13 Service App Data store App Service
  20. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Serve slow clients 14 Server
  21. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Serve slow clients 15 Server
  22. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Use Case: Push message to client 16 Server Message Broker
  23. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Live (continuous) database queries ! UI event handling (Android) ! Big Data ! Real time analytics ! HTTP/2 17 Other use cases
  24. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! A form of computer timing control protocol ! Starts processing after receiving a signal ! Completed eventually 18 Asynchronous
  25. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Introduces concurrency ! Does not block the caller • At least in the first place ! Keeps more Threads busy 19 Asynchronous
  26. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Unit of execution • Runnable ! Executor • Thread • ThreadPool 20 Asynchronous: Requirements
  27. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Asynchronous: Future 21 AsyncRestTemplate asyncRestTemplate = … AsyncCassandraTemplate asyncCassandra = … SettableListenableFuture<String> future = new SettableListenableFuture<>(); asyncRestTemplate.getForEntity("https://slow-service.com", String.class) .addCallback(response -> { Page page = new Page(); page.setId(…); page.setContent(response.getBody()); ListenableFuture<Page> insertFuture = asyncCassandra.insert(page); insertFuture.addCallback(savedPage -> future.set("OK"), failure -> future.setException(failure)); }, failure -> failure -> future.setException(failure)); return future;
  28. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Asynchronous: Future 22 AsyncRestTemplate asyncRestTemplate = … AsyncCassandraTemplate asyncCassandra = … SettableListenableFuture<String> future = new SettableListenableFuture<>(); asyncRestTemplate.getForEntity("https://slow-service.com", String.class) .addCallback(response -> { Page page = new Page(); page.setId(…); page.setContent(response.getBody()); ListenableFuture<Page> insertFuture = asyncCassandra.insert(page); insertFuture.addCallback(savedPage -> future.set("OK"), failure -> future.setException(failure)); }, failure -> failure -> future.setException(failure)); return future;
  29. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Asynchronous: Future 23 AsyncRestTemplate asyncRestTemplate = … AsyncCassandraTemplate asyncCassandra = … SettableListenableFuture<String> future = new SettableListenableFuture<>(); asyncRestTemplate.getForEntity("https://slow-service.com", String.class) .addCallback(response -> { Page page = new Page(); page.setId(…); page.setContent(response.getBody()); ListenableFuture<Page> insertFuture = asyncCassandra.insert(page); insertFuture.addCallback(savedPage -> future.set("OK"), failure -> future.setException(failure)); }, failure -> failure -> future.setException(failure)); return future;
  30. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Asynchronous: Future 24 AsyncRestTemplate asyncRestTemplate = … AsyncCassandraTemplate asyncCassandra = … SettableListenableFuture<String> future = new SettableListenableFuture<>(); asyncRestTemplate.getForEntity("https://slow-service.com", String.class) .addCallback(response -> { Page page = new Page(); page.setId(…); page.setContent(response.getBody()); ListenableFuture<Page> insertFuture = asyncCassandra.insert(page); insertFuture.addCallback(savedPage -> future.set("OK"), failure -> future.setException(failure)); }, failure -> failure -> future.setException(failure)); return future;
  31. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Say „callback“ to a JavaScript developer and he will start crying instantaneously! – Venkat Subramaniam 25
  32. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 26 Using Java types Non- Blocking Streaming Pattern Future<T> x Pull CompletableFuture<T> x Push Stream<T> x Pull Iterator<T> x Pull Input/OutputStream x Pull
  33. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Available since Java 8 ! Functional composition ! Functional transformation 27 Asynchronous: CompletableFuture
  34. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Asynchronous: CompletableFuture example 28 CompletableFuture<ResponseEntity<String>> future = … future.thenCompose(response -> { Page page = new Page(); page.setId(…); page.setContent(response.getBody()); return asyncCassandra.insert(page); }).thenApply(Page::getId);
  35. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 29 Concurrency effects public static class Test extends Thread { boolean keepRunning = true; public void run() { long count = 0; while (keepRunning) { count++; } System.out.println("Thread terminated after cycles: " + count); } } public static void main(String[] args) throws InterruptedException { Test t = new Test(); t.start(); System.out.println("Started"); Thread.sleep(1000); t.keepRunning = false; System.out.println("keepRunning set to false."); }
  36. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Understanding the Java Memory Model is hard. Getting concurrency right is harder. 30
  37. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Effects of an async fetch model 31 Request I/O
  38. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Effects of an async fetch model 31 Request I/O
  39. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Effects of an async fetch model 31 Request I/O
  40. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Effects of an async fetch model 31 Request I/O
  41. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Effects of an async fetch model 31 Request I/O Requires synchronization
  42. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Effects of an async fetch model 31 Request I/O Requires synchronization Still waiting, eh?
  43. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Effects of an async fetch model 31 Request I/O Requires synchronization Still waiting, eh?
  44. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Makes assumptions over resource usage ! Need a change • Change programming model 32 Imperative programming
  45. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ We need a different toolset! 33
  46. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ We need a different toolset! 34
  47. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Allows building and composing asynchronous applications ! Reacts to the availability of resources ! Requires a reactive API 35 Reactive programming model
  48. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Collaborative initiative to provide a standard for asynchronous stream processing with non-blocking back pressure. ! Co-designed by Twitter, Lightbend, Pivotal, Netflix and many others ! De-facto interop standard ! Java 9: Flow API 36 Reactive Streams
  49. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Publisher and Subscriber 37 Subscriber Publisher Subscribe Data
  50. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Publisher and Subscriber 37 Subscriber Publisher Subscribe Data
  51. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Publisher and Subscriber 37 Subscriber Publisher Subscribe Data
  52. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 38 Distributions org.reactivestreams:reactive-streams • Publisher • Subscriber • Subscription • Processor • Flow.Publisher • Flow.Subscriber • Flow.Subscription • Flow.Processor Part of Java 9 in java.util.concurrent
  53. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Apply a wide range of operators: map, split, merge, delay RxJava 1 & 2 Project Reactor Akka Streams 39 Reactive libraries
  54. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 40 Reactive APIs on the JVM Reactive API Reactive Streams
 Type Non-Reactive
 Streams Type RxJava 1 Observable
 Single
 Completable RxJava 2 Flowable Observable
 Single
 Maybe,Completable Akka Streams 2 Source
 Sink
 Flow Project Reactor Mono
 Flux
  55. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 41 Reactive APIs on the JVM: Generations Reactive API Generation Support RxJava 1 2nd Limited back pressure RxJava 2 4th Reactive Streams + operator fusion Akka Streams 2 3rd Reactive Streams + actor fusion Project Reactor 4th Reactive Streams + operator fusion
  56. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Use Reactor if • using Java 8 ! Use RxJava if • stuck with Java 6 • need checked Exceptions in functions 42 RxJava 2 or Project Reactor
  57. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! „Volume knob“ for data emission ! Communicates demand (capacity) of the subscriber to the publisher 43 Back pressure
  58. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Request all the data ! Now 44 Asynchronous fetch model AsyncHttpClient c = …; for (int i = 0; i < 10; i++) { HttpGet get = new HttpGet("https://google.com"); Future<HttpResponse> response = c.execute(get); // … }
  59. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Asynchronous fetch model 45
  60. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Asynchronous fetch model 45 Remote App Remote Remote App can’t keep up (Back pressure)
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Asynchronous fetch model 45 Remote App Remote Remote App can’t keep up (Back pressure)
  62. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Publisher and Subscriber 46 Subscriber Publisher Publish as fast as possible
  63. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 47 Publisher<T>
  64. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 47 Publisher<T> I/O thread push
  65. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Back pressure control 48 Subscriber Publisher Demand
  66. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Back pressure control 49 Subscriber Publisher Demand
  67. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 50
  68. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 50 Data store App
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 50 Data store App Data store
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 50 Data store App Data store Data store
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 50 Data store App Data store Data store Data store App
  72. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 50 Data store App Data store Data store Data store App
  73. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Introduction to Project Reactor
  74. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ How do you achieve asynchronous, non-blocking processing? Without losing your mind? 52
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 54
  77. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 55 List<T> Iterator<T> Future<T> Future<List<T>>
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 55 List<T> Iterator<T> Future<T> Future<List<T>> .get() for-each .hasNext()
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 55 List<T> Iterator<T> Future<T> Future<List<T>> .get() for-each .hasNext() Request thread pulls
  80. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 56 Publisher<T>
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 56 Publisher<T> Thread pushes data
  82. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 57 Iterable<T> Iterator<T> Publisher<T> Subscriber<T>
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 57 Iterable<T> Iterator<T> Publisher<T> Subscriber<T> vs.
  84. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 58 Subscriber Publisher feedback push events produces consumes Relation between Publisher and Subscriber
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 59 Subscriber Publisher feedback push events produces consumes interfaces from Reactive Streams spec Relation between Publisher and Subscriber
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 60 Subscriber Publisher feedback 0..N elements + 0..1 (complete | error) produces consumes Signals
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 61 Subscriber Publisher push events produces consumes Demand (Back pressure control) Back pressure
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 62 Subscriber Publisher push events produces consumes can I have an API though?
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 63 Subscriber Publisher push events produces consumes
  90. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 64 Project Reactor 3
  91. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Composing asynchronous & event-based sequences, using non-blocking operators ! Without sacrifice • No callback hell • No Futures ! End to end Reactive Streams 65 Project Reactor
  92. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Duration ! CompletableFuture ! Stream 66 Focus on Java 8
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Project Reactor Types 67 Mono<T> Flux<T>
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Project Reactor Types 67 Mono<T> Flux<T> 0..1..Error 0..N..Error
  95. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 68 This is the timeline of the Flux. Time flows from left to right. These are items emitted by the Flux. This vertical line indicates that the Flux has completed successfully. These dotted lines and this box indicate that a transformation is being applied to the Flux. The text inside the box shows the nature of the transformation. If for some reason the Flux terminates abnormally, with an error, the vertical line is replaced by an X. This Flux is the result of the transformation. operator 1 2 3 4 5 6 1 2 3 Explaining reactive operations
  96. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Explaining reactive operations 69 Transformed Completion signal Error signal Emitted element Time
  97. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Flux 70 These are items emitted by the Flux. operator 1 2 3 4 5 6 1 2 3
  98. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Mono 71 This is the eventual item emitted by the Mono. operator 1 1
  99. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 72 Operators an Rx-inspired API with a vocabulary of operators similar to RxJava...
  100. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 73 Operators an Rx-inspired API ...but not exactly the same
  101. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 74 Flux/Mono generator operator operator operator nothing happens until you subscribe
  102. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 75 Flux/Mono generator Subscriber operator operator operator nothing happens until you subscribe
  103. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Flux/Mono generator Subscriber operator operator operator Sub Sub Sub per Subscription state
  104. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ data flows Flux/Mono generator Subscriber operator operator operator Sub Sub Sub
  105. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Reactor is agnostic ! Facilitates switching ! Schedulers 78 Threading (contexts)
  106. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! single: Single-Threaded scheduler ! elastic: Grows (unbounded) as needed • used for I/O offloading ! parallel: Fixed-sized at number of CPU cores • Event-Loop ! timer: Timed tasks 79 Schedulers
  107. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! publishOn • switch emission of the Publisher on a thread ! subscribeOn • make the subscription and request happen on a particular thread 80 Context switching
  108. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 81 Flux/Mono generator operator subscribeOn operator publishOn operator operator Subscriber Sub Sub Sub Sub Sub Sub
  109. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 82 Flux/Mono generator operator subscribe On operator publish On operator operator Subscriber Sub Sub Sub Sub Sub Sub
  110. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 83 Flux/Mono generator operator subscribeOn operator publishOn operator operator Subscriber Sub Sub Sub Sub Sub Sub
  111. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 84 Flux/Mono generator operator subscribeOn operator publishOn operator operator Subscriber Sub Sub Sub Sub Sub Sub
  112. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 85 Flux/Mono generator operator subscribeOn operator publishOn operator operator Subscriber Sub Sub Sub Sub Sub Sub
  113. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 86 Flux/Mono generator operator subscribeOn operator publishOn operator operator Subscriber Sub Sub Sub Sub Sub Sub
  114. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Operator time! map, filter, buffer 87
  115. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 88 Flux.range Subscriber map filter buffer
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 92 Flux.range Subscriber map filter buffer
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 93 Flux.range Subscriber map filter buffer
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 94 Flux.range Subscriber map filter buffer
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 95 Flux.range Subscriber map filter buffer
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 96 Flux.range Subscriber map filter buffer
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 97 Flux.range Subscriber map filter buffer
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 98 Flux.range Subscriber map filter buffer
  126. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 99 Flux.range(5, 3) .map(i -> i + 3) .filter(i -> i % 2 == 0) .buffer(3)
  127. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 100 Flux.range(5, 3) .map(i -> i + 3) .filter(i -> i % 2 == 0) .buffer(3) 5, 6, 7 | 8, 9, 10 | 8, 10 | [8,10]|
  128. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Operator time²! flatMap all the things 101
  129. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Asynchronous sub-process ! Map to 0, 1 or N elements 102 flatMap operator
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 103
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 106 flatMap(user -> tweetStream(user))
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 107 flatMap(user -> tweetStream(user))
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 108 flatMap(user -> tweetStream(user))
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 109 flatMap(user -> tweetStream(user))
  137. Unless otherwise indicated, these slides are 
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    Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Coding Time!
  138. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Spring WebFlux
  139. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! It’s all about efficient resource usage ! Turn around the idea of imperative programming ! React to the availability of resources 112 What is Reactive Spring
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Scaling 113
  141. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Scaling 113
  142. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Scaling 113
  143. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Spring WebFlux – Reactive web applications ! Spring Data – Reactive data store support ! Spring Cloud Stream – Message-driven microservices ! Spring Boot – Reactive auto configuration ! Spring Security – Security for reactive web applications ! Spring Cloud Gateway – API Gateway 114 Reactive Spring portfolio
  144. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Spring’s reactive web framework ! End to end non-blocking and asynchronous execution 115 What is WebFlux?
  145. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Project Reactor 3.0 ! Spring Framework 5.0 ! Optional: Spring Boot 2.0 116 Requirements
  146. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 117
  147. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Servlet API is thread-bound ! Servlet API has no native HTTP/2 support (yet) ! No notion of back pressure ! SSE API’s (Server-sent events) are vendor-specific 118 Y U no Servlet API?
  148. Unless otherwise indicated, these slides are 
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    Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Coding Time!
  149. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Allows usage of Reactive types ! Improves asynchronous usage (DeferredResult) ! Improves SSE streaming usage (ResponseBodyEmitter) ! Everything else is blocking 120 Spring Web MVC
  150. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive Spring Data
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 122 Request Data access Remote data service
  152. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 122 Request Data access Remote data service
  153. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 122 Request Data access Remote data service I/O Wait
  154. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 122 Request Data access Remote data service I/O Wait
  155. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 122 Request Data access Remote data service I/O Wait This one is waiting
  156. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 122 Request Data access Remote data service I/O Wait This one is waiting
  157. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 123 Request Data access Remote data service
  158. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 123 Request Data access Remote data service Bulk fetch
  159. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 123 Request Data access Remote data service Multiple calls Bulk fetch
  160. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 123 Request Data access Remote data service Multiple calls Bulk fetch
  161. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Accessing data today 123 Request Data access Remote data service Multiple calls Bulk fetch
  162. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Keep resources busy ! Connection contention ! Usually synchronous/blocking ! Multiple requests ! Asynchronous isn’t always a good answer 124 Todays’ data access
  163. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Project Reactor 3.0 ! Spring Framework 5.0 ! Spring Data 2.0 ! A reactive (asynchronous, ideally non-blocking) driver ! Optional: Spring Boot 2.0 125 Requirements for Reactive Spring Data
  164. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Project Reactor 3.0 ! Spring Framework 5.0 ! Spring Data 2.0 ! A reactive (asynchronous, ideally non-blocking) driver ! Optional: Spring Boot 2.0 125 Requirements for Reactive Spring Data
  165. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Reactive Template API ! Reactive Repository support ! Reduced feature set 126 Reactive Spring Data
  166. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! MongoDB ! Apache Cassandra ! Redis ! Couchbase 127 Reactive Spring Data modules
  167. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! JDBC is a blocking API ! JPA is a blocking API ! Sorry, no reactive JPA support so far 128 What about JPA
  168. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Not a priority but feasible • Neo4j • Solr • ElasticSearch 129 Future reactive Spring Data modules
  169. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Non-blocking I/O ! Threading-infrastructure ! Back pressure ! Integration with reactive libraries 130 Why reactive drivers?
  170. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 131
  171. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 131 Data store App
  172. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 131 Data store App Data store
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    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 131 Data store App Data store Data store
  174. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 131 Data store App Data store Data store Data store App
  175. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Reactive fetch model 131 Data store App Data store Data store Data store App
  176. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 132 Imperative Template API <T> T insert(T objectToSave) void insertAll(Collection<…> objects)
  177. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 133 Reactive Template API <T> Mono<T> insert(T objectToSave) <T> Mono<T> insert(Mono<T> objectToSave)
  178. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 134 Reactive Repository API public interface ReactivePersonRepository extends ReactiveCrudRepository<Person, String> {
 
 Flux<Person> findByLastname(String lastname);
 
 @Query("{ 'firstname': ?0 }")
 Mono<Person> customQuery(String firstname); Flux<Person> findByLastname(Mono<String> lastname); }
  179. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 135 Reactive Repository API public interface ReactivePersonRepository extends ReactiveCrudRepository<Person, String> {
 
 Flux<Person> findByLastname(String lastname);
 
 @Query("{ 'firstname': ?0 }")
 Mono<Person> customQuery(String firstname); Flux<Person> findByLastname(Mono<String> lastname); }
  180. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 136 Reactive Repository API public interface ReactivePersonRepository extends ReactiveCrudRepository<Person, String> {
 
 Flux<Person> findByLastname(String lastname);
 
 @Query("{ 'firstname': ?0 }")
 Mono<Person> customQuery(String firstname); Flux<Person> findByLastname(Mono<String> lastname); }
  181. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 137 Reactive Repository API public interface ReactivePersonRepository extends ReactiveCrudRepository<Person, String> {
 
 Flux<Person> findByLastname(String lastname);
 
 @Query("{ 'firstname': ?0 }")
 Mono<Person> customQuery(String firstname); Flux<Person> findByLastname(Mono<String> lastname); }
  182. Unless otherwise indicated, these slides are 
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    Software, Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Coding Time!
  183. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Blocking driver ! Reactive driver ! Requires both drivers and two connections ! Collection operations (CRUD, Geo-commands) ! Aggregation streaming ! No GridFS, MapReduce, Grouping support in Spring Data 139 Reactive MongoDB
  184. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Asynchronous driver (adoption layer) ! Feature parity ! Optional: Asynchronous Template API with ListenableFuture 140 Reactive Apache Cassandra
  185. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Reactive driver (used for blocking operations as well) ! Reactive Template API ! Planned: Reactive Pub/Sub ! No Reactive Repository support 141 Reactive Redis
  186. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Reactive driver (used for blocking operations as well) ! Reactive Template API ! Reactive Repository support 142 Reactive Couchbase
  187. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Going Reactive
  188. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Change your mindset ! Non-blocking • I/O • Computation ! Consider if reactive is benefit or burden 144 What does it take to go reactive?
  189. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Carefully consider whether it makes sense ! Functional-reactive programming is a good answer for a certain class of problems ! Can improve code ! Can clutter code 145 Existing applications
  190. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Get familiar with the vocabulary • Asynchronous • non-blocking • back pressure • reactive • reactive extensions • streams operators 146 Reactive language
  191. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Don’t implment Reactive Streams interfaces yourself • Unless you’re trying the RS TCK to pass ! Reactive Streams is just the contract • Use a reactive composition library ! Nothing happens until subscription 147 Reactive Streams
  192. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ! Carefully select your tools • API • Drivers ! Tooling is important ! Define code styles ! Learn reading the stack trace 148 Reactive composition library
  193. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 149 … at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:926) at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:134) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:644) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:579) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:496) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:458) at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858) at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory at java.lang.Thread.run(Thread.java:745)
  194. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 150 java.lang.NullPointerException: The mapper returned a null value. at java.util.Objects.requireNonNull(Objects.java:228) at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:37 at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:37 at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76) at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:37 at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java: at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:37 at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:37 at reactor.core.publisher.FluxFlatMap$FlatMapMain.innerNext(FluxFlatMap.java:778)
  195. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 151 Assembly trace from producer [reactor.core.publisher.MonoMapFuseable] : reactor.core.publisher.Mono.map(Mono.java:2126) org.springframework.data.redis.core.DefaultReactiveValueOperations.lambda$get$12(DefaultRea org.springframework.data.redis.core.DefaultReactiveValueOperations.lambda$createMono$23(Def org.springframework.data.redis.core.ReactiveRedisTemplate.doInConnection(ReactiveRedisTempl org.springframework.data.redis.core.ReactiveRedisTemplate.lambda$createMono$1(ReactiveRedis reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:45) reactor.core.publisher.MonoSwitchIfEmpty.subscribe(MonoSwitchIfEmpty.java:44) reactor.core.publisher.Mono.block(Mono.java:1263) workshop.CachingController.getOrCreate(CachingController.java:44) org.springframework.web.reactive.result.method.InvocableHandlerMethod.doInvoke(InvocableHan org.springframework.web.reactive.result.method.InvocableHandlerMethod.lambda$invoke$0(Invoc
  196. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 152 Error has been observed by the following operator(s): |_ Mono.map(DefaultReactiveValueOperations.java:157) |_ Flux.from(ReactiveRedisTemplate.java:296) |_ Flux.doOnSignal(ReactiveRedisTemplate.java:296) |_ Mono.from(ReactiveRedisTemplate.java:272) |_ Mono.defer(ReactiveRedisTemplate.java:272) |_ Mono.switchIfEmpty(CachingController.java:44) |_ Mono.error(InvocableHandlerMethod.java:127) |_ Mono.flatMap(InvocableHandlerMethod.java:116) |_ Mono.doOnSignal(RequestMappingHandlerAdapter.java:191) |_ Mono.error(RequestMappingHandlerAdapter.java:215) |_ Mono.onErrorResume(RequestMappingHandlerAdapter.java:192) |_ Mono.defer(RequestMappingHandlerAdapter.java:189) |_ Mono.then(RequestMappingHandlerAdapter.java:189) |_ Mono.flatMap(DispatcherHandler.java:129) |_ Mono.flatMap(DispatcherHandler.java:130) |_ Mono.error(ResponseStatusExceptionHandler.java:47) |_ Mono.onErrorResume(ExceptionHandlingWebHandler.java:67)
  197. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Questions? Mark Paluch • @mp911de
  198. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software,

    Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Resources ! Code - Repository @ Github ! Reactor Rx Lite API – Repository @ Github ! Spring Data Examples – Repository @ Github ! Spring projects release calendar – Google Calendar 154 @mp911de