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Reactive clean architecture
The document discusses reactive clean architecture and emphasizes architecture as intent, focusing on use cases, dependencies, and testability independent of frameworks. It outlines a layered architecture approach combining interactors, repositories, and a presentation layer, demonstrating data flow and interaction patterns. Additionally, it includes practical advice on handling technical debt, starting small, and the importance of testing.
Reactive clean architecture
- 1. Reactive Clean Architecture ViktorNyblom @qw4z1
- 2. MVP MVC MVVM Whatisn’t Architecture X X X
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- 4. Architecture is aboutIntent - Uncle Bob
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- 7. Key points ! UseCases ! Dependencies ! Models ! Reactive ! Testable ! Independent of frameworks
- 8. What is aUse Case? ! Captures application business rules ! Independent of framework ! Shows WHAT the application does, not HOWX Interactor
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- 11. Three Layers DataPresentation Domain Model PresenterViewInteractor Model Operation API Repository Cache DBAbstraction
- 12. Presentation data flow ViewPresenter D O M A I N User interaction onRefresh() execute() domainData format() showData(data) Get Feed Interactor fun getFeed(): Single<List<Tweets>>
- 13. What if wecould observe a stream of data forever and react to new versions of that data?
- 14. Presentation data flow ViewPresenter D O M A I N User interaction onRefresh() execute() domainData format() updateData(data) Refresh Feed Interactor Observe Feed Interactor Create Tweet Interactor execute()onCreateTweet()
- 15. interface TweetFeedContract.Presenter : BasePresenter<TweetFeedContract.View>{ fun onRefresh() ... } Presentation
- 16. interface TweetFeedContract.View : BaseView{ fun updateFeed(list: List<DisplayableTweet>) fun showEmpty() fun showLoading() .... } Presentation
- 17. class TweetFeedPresenter @Injectconstructor( private val refreshFeedInteractor: RefreshFeedInteractor, private val observeFeedInteractor: ObserveFeedInteractor, private val mapToDisplayableItem: Mapper<DisplayableItem> ) : TweetFeedContract.Presenter { private val disposables: CompositeDisposable ... } Presentation
- 18. override fun onRefresh(){ refreshFeedInteractor.excecute() } TweetFeedPresenter
- 19. override fun onAttach(view:TweetFeedContract.View) { this.view = view disposables += bindToFeed() } TweetFeedPresenter
- 20. override fun bindToFeed():Disposable = observeFeedInteractor .excecute() .onSubscribe { view?.showLoading() } .map(mapToDisplayableItem) .subscribe( { tweets -> if (tweets.notEmpty()) view?.updateFeed(tweets) else view?.showEmpty() }, { throwable -> loge(throwable) } ) TweetFeedPresenter
- 21. Models should makesense in the context where they are being used.
- 22. What the map? publicclass Item { private String validTo; private float price; private String validFrom; private int type; }
- 23. What the map? publicclass Item { @SerializedName ("validto") private String validTo; @SerializedName ("price") private float price; @SerializedName ("validfrom") private String validFrom; @SerializedName (value = "type") private int type; }
- 24. What the map? @DatabaseTable(name = “item") public class Item { @DatabaseField (generatedId = true) private int _id; @DatabaseField @SerializedName ("validto") private String validTo; @DatabaseField (canBeNull = false) @SerializedName ("price") private float price; @DatabaseField (canBeNull = false) @SerializedName ("validfrom") private String validFrom; @DatabaseField @SerializedName (value = "type") private int type; }
- 25. What the map? publicclass APIItem { private int validto; private float price; private int validfrom; private int type; } @DatabaseTable (name = “item") public class DatabaseItem { @DatabaseField (generatedId = true) private int _id; @DatabaseField private int validTo; @DatabaseField private float price; @DatabaseField private int validFrom; @DatabaseField private int type; @DatabaseField private boolean dirty; }
- 26. What the map? @DatabaseTable(name = “item") public class DatabaseItem { @DatabaseField (generatedId = true) private int _id; @DatabaseField private int validTo; @DatabaseField private float price; @DatabaseField private int validFrom; @DatabaseField private int type; @DatabaseField private boolean dirty; } public class DisplayableItem { private int _id; private DateTime validTo; private String formattedTo; private String formattedPrice; private DateTime validFrom; private String formattedFrom; private ItemType type; private boolean selected; }
- 27. What the map DataPresentationDomain Model PresenterView Interactor Model Operation API Repository Cache DBAbstraction
- 28. What the map DataPresentationDomain Presentation Model PresenterView Interactor Domain Model Operation API Repository Cache DBAbstraction API Model Cache Model
- 29. Domain data flow D A T A execute() domainDatadomainData Refresh Feed Interactor Abstraction :Tweet Repository P R E S E N TA T I O N Observe Feed Interactor onComplete() retrieveFeed() Abstraction : TweetList Repository onNext()
- 30. Interactors abstract class CompletableInteractor<inParams>( private val executionScheduler: Scheduler, private val postExecutionScheduler: Scheduler) { abstract fun buildInteractorCompletable(params: Params): Completable fun execute(params: Params): Completable = buildInteractorObservable(params) .subscribeOn(executionScheduler) .observeOn(postExecutionScheduler) .subscribe() }
- 31. Interactors class RefreshFeedInteractor @Injectconstructor( private val tweetRepository: TweetRepository, executionScheduler: Scheduler, postExecutionScheduler: Scheduler) : CompletableInteractor<FeedSpec>(executionScheduler, postExecutionScheduler) { override fun buildInteractorCompletable(params: FeedSpec): Completable = tweetRepository.refreshFeed(params) }
- 32. Interactors abstract class ObservableInteractor<T,in Params>( private val executionScheduler: Scheduler, private val postExecutionScheduler: Scheduler) { abstract fun buildInteractorCompletable(params: Params): Observable<T> fun execute(params: Params): Observable<T> = buildInteractorObservable(params) .subscribeOn(executionScheduler) .observeOn(postExecutionScheduler) .subscribe() }
- 33. Interactors class RefreshFeedInteractor @Injectconstructor( private val tweetListRepository: TweetListRepository, executionScheduler: Scheduler, postExecutionScheduler: Scheduler) : ObservableInteractor<List<Tweet>, FeedSpec>(executionScheduler, postExecutionScheduler) { override fun buildInteractorCompletable(params: FeedSpec): Observable<List<Tweet>> = tweetListRepository.observeFeed(params) } .filter { it.createdDate.after(someDate) } .compose { customTransformer }
- 34. interface TweetListRepository { funrefreshFeed(feedSpec: FeedSpec): Completable fun observeFeed(feedSpec: FeedSpec): Observable<List<Tweet>> }
- 35. class ReactiveTwitterRepository( private valapiMapper: ApiToStoreMapper, private val api: SomeApi, private val store: ReactiveStore) : TweetRepository { override fun refreshFeed(): Completable = api.retrieveTweetList() .map { apiMapper } .doOnSuccess { store.storeTweets(it) } .toCompletable() ... }
- 36. class ReactiveTwitterRepository( private valapiMapper: ApiToStoreMapper, private val domainMapper: StoreToDomainMapper, private val api: SomeApi, private val store: ReactiveStore) : TweetRepository { ... override fun getFeedObservable(feedSpec: FeedSpec): Observable<List<Tweet> = store.getFeedObservable() .map(domainMapper) ... }
- 37. interface ReactiveStore<Key, Value>{ fun storeSingle(item: Value): Completable fun storeAll(items: List<Value>): Completable fun replaceAll(items: List<Value>): Completable fun getSingle(key: Key): Observable<Value> fun getAll(): Observable<List<Value>> } ReactiveStore
- 38. ReactiveStore ! Coordinates puttingdata in persistence and/or cache ! Create, store and feed the stream ! Implementation depends on the application ! Single source of truth
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- 40. Final advices ! Bepragmatic ○ Some compromises are ok ○ Perfect isn’t always best ! Beware of technical debt ○ Every debt will be collected some day ! Start out small ○ Get a feel for the structure ○ Decide on whether it’s the best approach for your app ! Don’t forget the tests!
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