reactive programming in spring 5

Reactive Programming in Spring 5

Arjen PoutsmaPivotal

About Arjen

• Twenty years of experience in Enterprise Software Development

• Joined SpringSource in 2005

• Development lead of Spring Web Services, Spring REST support, Spring Scala

• Working on Spring 5

Agenda

• Reactive Systems

• Reactive Streams

• RxJava

• Reactor

• Reactive Programming in Spring 5

Reactive Systems

Reactive Manifesto

Responsive

Message Driven

ResilientElastic

Reactive Manifesto• Responsive

• Rapid

• Consistent

• Resilient

• Replication

• Isolation

• Elastic

• Scaling

• No bottlenecks

• Message Driven

• Async

• Back-pressure

Reactive Streams

Reactive Streams Spec

• Focus on Interoperability

• No operators

• Wide support

• Akka, Vert.x, RxJava, Ratpack

• JDK 9 Flow in java.util.concurrent

Publisher Subscriber

Publisher Subscribersubscribe

Publisher Subscriber

Publisher Subscriber

Publisher Subscriber

onSubscribe

Subscription

Publisher Subscriber

Subscription

Subscription

Publisher Subscriber

Subscription

Publisher Subscriber

request

2

Subscription

Publisher Subscriber

2

Subscription

Publisher Subscriber

2

Subscription

Publisher Subscriber

onNext

1

Subscription

Publisher Subscriber

1

Subscription

Publisher Subscriber

onNext

0

Subscription

Publisher Subscriber

0

Subscription

Publisher Subscriber

request

5

Subscription

Publisher Subscriber

5

Subscription

Publisher Subscriber

5

Subscription

Publisher Subscriber

onNext

4

Subscription

Publisher Subscriber

4

Subscription

Publisher Subscriber

onNext

3

Subscription

Publisher Subscriber

3

Subscription

Publisher Subscriber

onNext

2

Subscription

Publisher Subscriber

2

Subscription

Publisher Subscriber

onComplete

2

Publisher Subscribersubscribe

onSubscribeSubscription

request

onNext

onComplete

onError

Hot & Cold

Cold Hot

Passive Active

Publish when subscribed

Publish regardless

Queue Mouse Movement

Operators

• map, flatMap, take, subscribe, …

• No Operators in Reactive Streams

• Left to implementations

Reactor

Project Reactor

• Stream extends Publisher

• Wrap Publisher

Reactor

Streams.just('a' 'b' 'c') .take(2) .map(Character::toUpperCase) .consume(System.out::println);

RxJava

RxJava

• Based On Reactive Extensions

• Ported to many languages

• Rx.NET, RxJava, RxJS, ...

• Native support for Reactive Streams coming in 2.x

RxJava

Observable.just('a', 'b', 'c') .take(2) .map(Character::toUpperCase) .subscribe(System.out::println)

RxNetty

• RxJava on top of Netty

• Client/server for TCP and HTTP

• Backpressure support

Spring 5

Spring Reactive

• Experimental work for Spring 5

• Non-blocking runtimes:

• Netty, Jetty, Tomcat, (Undertow)

• RxJava, Reactor

https://github.com/spring-projects/spring-reactive

public interface ServerHttpRequest { HttpMethod getMethod(); URI getURI(); InputStream getBody(); }

public interface ServerHttpResponse { void setStatusCode(HttpStatus status); OutputStream getBody();}

HttpMessage

public interface ReactiveServerHttpRequest { HttpMethod getMethod(); URI getURI(); Publisher<ByteBuffer> getBody(); }

public interface ServerHttpResponse { void setStatusCode(HttpStatus status); Publisher<void> setBody(Publisher<ByteBuffer> body);}

Reactive HttpMessage

Reactive Wep App

Web Service Data

Wanted: Reactiveness• JDBC

• MySQL

• Postgres

• NoSQL

• MongoDB

• HTTP Client

• OkHttp

• Spring 5

• …

Reactor

@RequestMapping("/capitalize")@ResponseBodypublic Stream<Person> capitalize(

@RequestBody Stream<Person> persons) { return persons.map(person -> { person.setName(person.getName().toUpperCase()); return person; });}

RxJava

@RequestMapping("/capitalize")@ResponseBodypublic Observable<Person> capitalize(

@RequestBody Observable<Person> persons) { return persons.map(person -> { person.setName(person.getName().toUpperCase()); return person; });}

More Spring!

Spring Meetup

http://www.meetup.com/Dutch-Spring-Meetup/

Spring Track GOTO Amsterdam 2016

http://gotoams.com

Q & A

https://github.com/spring-projects/spring-reactive