ºÝºÝߣ

ºÝºÝߣShare a Scribd company logo

The Next Step for Reactive Android Programming

?Download as PPTX, PDF?
?
Tomasz Polanski
Tomasz Polanski

This presentation is mainly for the participants of DevFest Berlin 2016. For the rest, a blog post is soon coming so the presentation won't be without the context. I will talk about our experience of migrating a highly reactive application, used by millions of users, from RxJava 1.x to 2.x. Firstly, I will share the advantages and disadvantages of moving to this new milestone release, so you can decide if it¡¯s worth to migrate your application. I will then focus on possible migration approaches; which strategies worked for me and which did not. Finally, we can discuss the frustrations that you need to prepare yourself for and how you can avoid them.

1 of 105
Download to read offline
Reactive Android: The Next Steps Futurice & upday @tpolansk Tomek Polanski
The Good @tpolansk
Reactive Streams compatibility @tpolansk[1]
4 interfaces 7 methods @tpolansk
Flowable.just("- I'm RxJava!") @tpolansk
Flowable.just("- I'm RxJava!") @tpolansk RxJava 2
Flux.from(Flowable.just("- I'm RxJava!")) @tpolansk RxJava 2
Flux.from(Flowable.just("- I'm RxJava!")) @tpolansk RxJava 2 Reactor 3
Flux.from(Flowable.just("- I'm RxJava!")) .map(msg -> msg + " - I'm Reactor!") @tpolansk RxJava 2
Flux.from(Flowable.just("- I'm RxJava!")) .map(msg -> msg + " - I'm Reactor!") @tpolansk Reactor 3 RxJava 2
Flux.from(Flowable.just("- I'm RxJava!")) .map(msg -> msg + " - I'm Reactor!") .subscribe(msg -> print(msg)); @tpolansk RxJava 2
Flux.from(Flowable.just("- I'm RxJava!")) .map(msg -> msg + " - I'm Reactor!") .subscribe(msg -> print(msg)); @tpolansk RxJava 2 Reactor 3 [2]
Backpressure @tpolansk
Backpressure Flowable & Observable @tpolansk
Flowable: BUFFER, DROP,¡­ @tpolansk
Observable: Buffer-like @tpolansk
Observable: Buffer-like @tpolansk Out Of Memory
Flowable? @tpolansk
@tpolansk
Flowable Exception Is Really Likely @tpolansk
Observable Exception Is Not Likely @tpolansk
Better Single and Completable Integration @tpolansk
Observable.range(0, 10) .all(it -> it % 2 == 0) @tpolansk
Observable.range(0, 10) .all(it -> it % 2 == 0) @tpolansk RxJava 1 - Observable
@tpolansk RxJava 2 - Single Observable.range(0, 10) .all(it -> it % 2 == 0)
Performance @tpolansk[3]
Performance (-76%, +2800%) @tpolansk[3]
Memory @tpolansk[3]
Memory 50% less @tpolansk[3]
Testing @tpolansk
Testing .test() @tpolansk
Observable.just(1) @tpolansk
Observable.just(1) .test() @tpolansk
Observable.just(1) .test() .assertValue(1) @tpolansk
Observable.just(1) .test() .assertValue(1) .assertComplete(); @tpolansk
Observable.just(1) .test() .assertValue(1) .assertComplete(); @tpolansk Soon in RxJava 1 [4]
Bye Bye nulls @tpolansk ¡°1B$ Mistake¡± no more [5]
The Bad @tpolansk
Bye Bye nulls @tpolansk Removing takes time
Writing Operators @tpolansk
10x HARDER* @tpolansk[6]
10x HARDER* @tpolansk
Android Dev¡¯s Nightmare @tpolansk
@tpolansk
@tpolansk
@tpolansk Styling?
@tpolansk Styling?
@tpolansk Styling?
Dex Limit @tpolansk
RxJava 1.2.2 5600 @tpolansk
RxJava 2.0.1 9200 @tpolansk
5600 + 9200 = 14800 @tpolansk
5600 + 9200 = 14800 22% Dex Limit @tpolansk
The Migration @tpolansk
upday¡¯s RxJava integration @tpolansk
Observable: 1224 @tpolansk
Observable: 1224 @tpolansk
Observable: 1224 int: 1516 @tpolansk
Observable: 1224 int: 1516 @tpolansk
Observable: 1224 int: 1516 String: 3246 @tpolansk
Observable: 1224 int: 1516 String: 3246 @tpolansk
Not in One Go! @tpolansk
Update to The Newest RxJava 1.x.x @tpolansk[7]
Use RxJava2Interop @tpolansk[8]
The Data Flow @tpolansk
@tpolansk Network UI
@tpolansk Network UI
@tpolansk Network UI
Start With Leafs Not Roots @tpolansk
// Activity dataModel.getText() .subscribe(text -> view.setText(text)); @tpolansk
// Activity dataModel.getText() .subscribe(text -> view.setText(text)); @tpolansk RxJava 1
// Activity RxJavaInterop .toV2Observable(dataModel.getText()) .subscribe(text -> view.setText(text)); @tpolansk
// Activity RxJavaInterop .toV2Observable(dataModel.getText()) .subscribe(text -> view.setText(text)); @tpolansk RxJava 1
// Activity RxJavaInterop .toV2Observable(dataModel.getText()) .subscribe(text -> view.setText(text)); @tpolansk RxJava 1 RxJava 2
// DataModel Observable<String> getText() { return cache.getText(); } @tpolansk
// DataModel Observable<String> getText() { return cache.getText(); } @tpolansk RxJava 1
// DataModel Observable<String> getText() { return RxJavaInterop .toV2Observable(cache.getText()); } @tpolansk
// DataModel Observable<String> getText() { return RxJavaInterop .toV2Observable(cache.getText()); } @tpolansk RxJava 2
// Activity RxJavaInterop .toV2Observable(dataModel.getText()) .subscribe(text -> view.setText(text)); @tpolansk RxJava 2
// Activity dataModel.getText() .subscribe(text -> view.setText(text)); @tpolansk RxJava 2
Replacing nulls @tpolansk
Replacing nulls Null Objects or Optionals @tpolansk[9]
class User { String name; User(String name) { this.name = name; } } @tpolansk
Observable<User> userStream = ¡­ @tpolansk
Observable<User> userStream = ¡­ ¡­ userStream .filter(user -> user != null) @tpolansk
class User { static final User EMPTY = new User(¡°¡±); String name; public User(String name) { this.name = name; } } @tpolansk
Observable<User> userStream = ¡­ ¡­ userStream .filter(user -> !user.equals(User.EMPTY)) @tpolansk
The Frustrating @tpolansk
NoSuchMethodError @tpolansk
NoSuchMethodError @tpolansk Wait for libs update!
@tpolansk First element?
@tpolansk .first(¡­) .firstOrError() .singleElement() .single(¡­) .singleOrError() .firstElement()
@tpolansk .first(¡­) .firstOrError() .singleElement() .single(¡­) .singleOrError() .firstElement() ?
@tpolansk Relearn some operators !
Migrating Tests @tpolansk
TestSubscriber<Integer> ts = new TestSubscriber<>(); Observable.just(1).subscribe(ts); ts.assertValue(1); @tpolansk
TestSubscriber<Integer> ts = new TestSubscriber<>(); Observable.just(1).subscribe(ts); ts.assertValue(1); @tpolansk
TestObserver<Integer> to = new TestObserver<>(); Observable.just(1).subscribe(to); to.assertValue(1); @tpolansk
Observable.just(1) .test() .assertValue(1); @tpolansk
Conclusion @tpolansk
RxJava 2 Is Better! @tpolansk
New Project? Definitely RxJava 2 @tpolansk
Almost Done Project? Should Not Migrate @tpolansk
Anything Between? It¡¯s Always Up to You @tpolansk
@tpolansk [1] Reactive Streams ¨C https://github.com/reactive-streams/reactive-streams-jvm [2] Reactor 3 - https://github.com/reactor/reactor-core [3] RxJava 2 Benchmark - https://github.com/akarnokd/akarnokd-misc/issues/2 [4] test() operator in v1 - https://github.com/ReactiveX/RxJava/pull/4777 [5] The Billion Dollar Mistake - https://www.infoq.com/presentations/Null- References-The-Billion-Dollar-Mistake-Tony-Hoare [6] Writing Operators - https://github.com/ReactiveX/RxJava/wiki/Writing- operators-for-2.0 [7] RxJava releases - https://github.com/ReactiveX/RxJava/releases [8] RxJava2Interop - https://github.com/akarnokd/RxJava2Interop [9] Simple Options - https://github.com/tomaszpolanski/Options

More Related Content

The Next Step for Reactive Android Programming