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Reactive programming for java developers
This document provides an overview of reactive programming and how it can be applied to Java applications using frameworks like Project Reactor and Spring WebFlux. It defines reactive programming as composing asynchronous and event-based streams using non-blocking operators. It discusses how reactive streams like Flux and Mono work in Project Reactor and how Spring WebFlux allows building reactive web applications that can handle high concurrency with low latency. Examples are provided of building reactive data repositories, handling streaming responses with backpressure, and orchestrating remote service calls reactively.
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Similar to Reactive programming for java developers
Reactive programming for java developers
- 1. Reactive Programming for JavaDevelopers Constantin PopaEngineering #5 16:00-16:45 Reactive Programming for Java Developers Constantin Popa
- 2. Reactive Programming for JavaDevelopers Constantin Popa
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- 4. Who here uses… Java8 Spring framework RxJava/Reactor Spring WebFlux
- 5. AGENDA Reactive Programming 101 Reactivestreams – Project Reactor Reactive web apps – Spring WebFlux
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- 9. async&blocking main thread time wait &join I/O I/O
- 10. async&nonblocking main thread time Event loop workerthread I/O request I/O request I/O Data available
- 11. how do achievethat? without losing your mind…
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- 13. “Composing asynchronous & event-basedstreams using non-blocking operators”
- 14. We don’t sacrificemuch callbacks? Future? CompletableFuture?
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- 18. Publisher Subscriber produces consumes pushevents Feedback interfaces from Reactive Streams specification now part of Java 9, under java.util.concurrent.Flow Subscriber<T> onNext(T) onComplete() onError(Throwable) onSubscribe(Subscription) 0..N elements + 0..1 (complete | error) backpressure These interfaces don’t do much… Subscription.request(n) Subscription.cancel()
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- 22. Give the Fluxa second chance
- 23. Interactive marble diagramson http://rxmarbles.com (most map to Reactor operators)
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- 26. Reactive streams vsJava 8 streams ”The design center for Streams is mostly about data that can be accessed with no latency (either from data structures or generating functions)” “The design center for Rx is about infinite streams of events which may arrive asynchronously.” Brian Goetz
- 27. an Rx-inspired API witha vocabulary of operators similar to RxJava
- 28. Flux.range map filter buffer Subscriber Nothinghappens until you subscribe
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- 33. Flux.range(1,3) .map( number ->toShape()) .filter(shape -> isCircle()) .buffer() .subscribe(shape -> printShape())
- 34. More awesomeness async sub-processeswith flatMap
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- 37. Flux.range(1,3) .map( number ->toShape()) .filter(shape -> isCircle()) .buffer() .subscribe(shape -> printShape())
- 38. Flux.range(1,3) .subscribeOn(Schedulers.elastic()) .map(number -> toShape()) .filter(shape-> isCircle()) .buffer() .publishOn(Schedulers.immediate()) .subscribe(shape -> printShape())
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- 40. Reactive web applicationsSpring WebFlux
- 41. Use case #1 Reactivedata repository
- 42. Let's recap: HTTP GETwith reactive data repository Designed to work with both Spring MVC and Spring WebFlux Simply return reactive types(Flux, Observable) from @Controller @GetMapping("/cars") @ResponseBody public Flux<Car> getCars() { return this.repository.findAll(); }
- 43. Flux<T>: finite collection orinfinite stream?
- 44. Use media typeto decide
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- 48. Use case #2 Responsestream with backpressure
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- 51. Let’s recap: HTTP GETwith streaming response Simply return reactive types(Flux, Observable) from @Controller Backpressure handling on both Spring MVC and Spring WebFlux
- 52. Use case #3 Reactiveremote service orchestration
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- 54. Let’s recap: Reactive webclient Orchestratenon-blocking, nested remote service calls with ease. Similar to reactive data access
- 57. What WebFlux isgood for: High traffic High concurrency with less hardware resources Latency, streaming scenarios
- 58. Summary Quite a steeplearning curve Doesn’t fit all scenarios, if it ain’t broken, don’t fix it It’s fun time to be a Java developer! Spring WebFlux and Reactor unlock the gates for easy Reactive Programming on the server side and not only