Erwin de Gier Real-world reactive programming in Java

@erwindeg github.com/erwindeg edegier.nl

Java 8 Streams vs. RX Observables

Pull vs. Push

Finite vs. Infinite

Sync vs. Async

Observable map() subscribe()

Iterable

Java 8 Streams vs. RX Observables

map()1 2 3 A B C forEach()

1 A2 B3 C

Java vs. Reactive Streams

Java 8 Streams vs. Reactive Streams

//IllegalState Exception

Reactive API

File IOHTTP

REST

Event bus

Persistence

Reactive Stack

Reactive Frameworks

VS.

Let

Reactive Overview

Framework

API

Event Model Annotations

Project Reactor

We are Blox

• Crypto positions

• Closed system

• Buy Crypto

• Sell Crypto

• Accounts

Architecture

Quote

Order

Market Exchange

RESTAPI

Command

Event

Query

RESTQuery

Quote Engine

REST

REST

Spring 5 Webflux

• Testing

• Spring Security

• Spring Cloud Hystrix

• Axon API’s: toFuture & fromFuture

WebFlux Testing

• @WebFluxTest(controllers = …)

• WebTestClient for WebFlux controller tests

• @MockBean for injected services

Spring Security

• Spring Security OAuth not working (legacy)

• Spring Security 5

•Misses OAuth Resource / Authorization server

Spring Security

SpringWeb

ZuulProxy

SpringWebFlux

RESTAPI

Auth Header

Response

Spring Security

• @EnableWebFluxSecurity

• Implement AuthenticationWebFilter

• Use http.addFilterAt(filter,order)

Spring Cloud Hystrix

• Cannot use the @HystrixCommand

• Use HystrixObservableCommand

• RxJava Observable vs Flux

Reactive Streams

Conclusion: state of reactive Java

• Libraries for reactive programming: Rx / Reactor

• Frameworks for async processes: Spring / Vert.x

• Expect to DIY

• Workarounds

e