hossaindoula / rxjava-katas

Building this Project

requirements

• maven 3

build

mvn clean install

Troubleshooting

• if you have troubles with failing Unittests, e.g. you are working offline or your internet connection is quite slow or unreliable:
  -> in WikiService you can enable mockmode globally by setting MOCKMODE = true

RxJava

getting started / DOKU

• http://reactivex.io/documentation/operators.html
• https://github.com/ReactiveX/RxJava/wiki
• http://rxmarbles.com/

RxJava 2 update

https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0

RxJava 1.x Timeline

• June 1, 2017 - feature freeze (no new operators), only bugfixes
• March 31, 2018 - end of life, no further development

important changes regarding upgrading from Rxjava 1.x

• Nulls (https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#nulls): RxJava 2.x no longer accepts null values
• Observable and Flowable (https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#observable-and-flowable): Observable is the non-backpressure Version and only Flowable supports backpressure.
• Subscription (https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#subscription): rx.Subscription has been renamed to io.reactivex.Disposable
• Schedulers (https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#schedulers): test() is no longer available in the Schedulers Class, use new TestScheduler()
• toBlocking -> blocking...

new features

• Maybe (https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#maybe): Conceptually, it is a union of Single and Completable providing the means to capture an emission pattern where there could be 0 or 1 item or an error signalled by some reactive source.
• Backpressure (https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#backpressure)
• Reactive-Streams compliance (https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#reactive-streams-compliance):
• Runtime hooks (https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#runtime-hooks): Hooks can now be changed at runtime. In 1.x you get an Exception if you change an hook in RxJavaPlugins

Reactor

getting started / DOKU

• http://projectreactor.io/docs

Reactor (3.0.5.RELEASE) vs. RxJava 2 (2.0.6)

• Java:
  - Reactor requires Java 8
  - RxJava requires Java 6
• Dependencies:
  - Reactor has reactive-streams, jsr305 (optional) and slf4j-api (optional) as dependencies
  - RxJava has only reactive-streams as a dependency
• Footprint (without dependencies):
  - Reactor: 1,1 MB
  - RxJava: 2.1 MB
• Debugging:
  - Reactor has a nice debugging feature (https://projectreactor.io/docs/core/release/reference/docs/index.html#_reading_a_stack_trace_in_debug_mode)
  - RxJava 2 has no direct support, but brings the basics to build debugging features (https://github.com/ReactiveX/RxJava/wiki/Plugins). For 1.x (maybe works also on 2.x, but not tested) exists an (outdated?) debugging module (https://github.com/ReactiveX/RxJavaDebug)
• Complexity:
  - Reactor is a bit smaller and has no "legacy" stuff like RxJava.
  - RxJava 2 is a bit more complex, regarding RxJava 1.x
• "Datatypes":
  - Reactor has just Mono(0-1) and Flux (0..n)
  - RxJava has Single (1), Maybe (0-1), Completable (0), Observable (0-n, no backpressure) and Flowable (0-n, backpressure)
• Doku (March 2017)
  - Reactor has a good, solid Doku with some TODO's/missing pats for some advanced Features
  - RxJava 2's Doku is not jet updated in total from 1.x to 2.x, but 1.x Doku is great.
• Testing:
  both have more or less equal testing support
• Operators:
  no relevant difference, both have all you need. Nice is that both have nearly the same signatures, so migration is quite simple and straight foreword.
• Performance (akarnokd/akarnokd-misc#2):
  - Reactor is generally 10-50% better in a Java 8 environment due to more inlined nature and even fewer allocations than RxJava 2
  - RxJava 2.x is generally better in terms of performance and memory utilization than 1.x; most lower performing components can be optimized further
• Interoperability:
  both use the reactive-streams API and it's no problem to mix both libraries, e.g use a Flowable in an Reactor operation and vice versa, convert between Flowable and Flux or use an Subscriber Impl from the other library.
• ...:
  - Reactor
  - RxJava

Spring reactive web

create a Microservice

• Go to https://start.spring.io, set the Spring Boot version to 2.0.0(SNAPSHOT) and add the "Reactive Web" starter.
• then you can have a look in https://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples/spring-boot-sample-webflux
• reference DOKU: http://docs.spring.io/spring-framework/docs/5.0.x/spring-framework-reference/html/web-reactive.html
• testing samples https://github.com/spring-projects/spring-framework/tree/master/spring-test/src/test/java/org/springframework/test/web/reactive/server/samples
• short article about WebClient usage and Streaming DATA https://spring.io/blog/2017/02/23/spring-framework-5-0-m5-update
• demos (looks a bit outdated) https://github.com/sdeleuze/spring-reactive-playground

Security / Context / ThreadLocal

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

Spring Data reactive

• https://spring.io/blog/2016/11/28/going-reactive-with-spring-data