Architecture and RxJava

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Architecture with RxJava

Jolanda Verhoef

Blendle

Makes the world’s best

journalism available to

everyone, everywhere

@lojanda

Blendle

Makes the world’s best

journalism available to

everyone, everywhere

@lojanda

Architecture

@lojanda

Mutable Data Stores

Context Stores

Mutable Data RepositoriesStatic Data

Repositories

Business Use Cases

Presenters

Custom Views Fragments Activities

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Reactive Programming

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Today’s subjects

Building standalone UI components

Building real standalone UI components

Synchronising UI components throughout the app

Updating lists after user interaction

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Today’s subjects

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Standalone UI componentsOpening the Blendle Reader

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Standalone UI componentsOpening the Blendle Reader

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Mutable Data Stores

Context Stores

Repositories

Business Use Cases

Presenters

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ArticlePreviewRepositorypublic Single<ArticlePreview> articlePreview$( String articleId ) { if ( cache.contains( articleId ) { return Single.just( cache.retrieve( articleId )); } else { return urlResolver.urlFor( articleId ) .flatMap( blendleApi::articlePreview$ ) .doOnSuccess( cache::store ); } }

@lojandaMutable Data Stores

Context Stores

Repositories

Business Use Cases

Presenters

GetArticlePreviewUseCase

public Single<ArticlePreview> execute( String articleId ) { return articleRepository.articlePreview$( articleId ) .subscribeOn( Schedulers.io() ) .observeOn( AndroidSchedulers.mainThread() ); }

Context Stores

Repositories

Business Use Cases

Presenters

ReaderPresenter

public void init( String articleId ) { getArticlePreviewUseCase.execute( articleId ) .subscribe( getView()::showArticlePreview, getView()::loadArticlePreviewFailed ); }

Context Stores

Repositories

Business Use Cases

Presenters

Today’s subjects

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Standalone UI components++Inside the Blendle Reader

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ReaderFragment

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ReaderFragment

Toolbar

Featured Image

RecyclerView

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ReaderFragment

Toolbar

Featured Image

RecyclerView

Publisher Logo

Bookmark Icon

Share Icon

Text Row

Image Row

……. Row

Mutable Data Stores

Context Stores

Repositories

Business Use Cases

Presenters

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ArticleContextStore

private BehaviorSubject<String> subject;

public void changeArticleContext( final String newArticleId ) { subject.onNext( newArticleId ); }

Context Stores

Repositories

Business Use Cases

Presenters

Reader@Override public View onCreateView( … ) { presenter.init( getArguments() != null ? getArguments().getInt( EXTRA_ARTICLE_ID ) : null ); }

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public void init( @Nullable String articleId ) { if( articleId == null) articleId = articleContextStore.getArticleContext(); loadData( articleId ); }

Mutable Data Stores

Context Stores

Repositories

Business Use Cases

Presenters

Today’s subjects

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Synchronising UI componentsBookmarking an article

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Mutable Data Stores

Context Stores

Repositories

Business Use Cases

Presenters

@lojanda

Mutable Data Stores

Context Stores

Repositories

Business Use Cases

Presenters

BookmarkStoreprivate Map<String, BehaviorSubject<Boolean>> subjectMap;

public BehaviorSubject<Boolean> getBookmarked( String articleId ) { if( subjectMap.contains( articleId ) return subjectMap.get( articleId ); BehaviorSubject<Boolean> subject = BehaviorSubject.create(); subjectMap.put( articleId, subject ); return subject; }

public void setBookmarked( String articleId, Boolean bookmarked ) { getBookmarked().onNext( bookmarked ); }

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BookmarkRepositorypublic Observable<Boolean> bookmarked$( String articleId ) { BehaviorSubject<Boolean> subject = bookmarkStore .getBookmarked( articleId );

if( ! subject.hasValue() ) { this.bookmarkedCall( articleId ) .subscribe( bookmarkStore::setBookmarked ); }

return subject; }

Context Stores

Repositories

Business Use Cases

Presenters

GetBookmarkUseCase

public Observable<Boolean> execute( String articleId ) { return bookmarkRepository.bookmarked$( articleId ) .subscribeOn( Schedulers.io() ) .observeOn( AndroidSchedulers.mainThread() ); }

Context Stores

Repositories

Business Use Cases

Presenters

BookmarkPresenter

public void init( String articleId ) { getBookmarkUseCase.execute( articleId ) .subscribe( getView()::showBookmarkValue ); }

Context Stores

Repositories

Business Use Cases

Presenters

Today’s subjects

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Updating listsArticle reading list

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Mutable Data Stores

Context Stores

Repositories

Business Use Cases

Presenters

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Mutable Data Stores

Context Stores

Repositories

Business Use Cases

Presenters

BookmarkStoreprivate PublishSubject<Pair<String, Boolean>> subject;

public Observable<Boolean> getBookmarkListener() { return subject; }

public void setBookmarked( String articleId, Boolean bookmarked ) { getBookmarked( articleId ).onNext( bookmarked ); subject.onNext( new Pair<>( articleId, bookmarked ); }

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ReadingListPresenterpublic void init() { bookmarkStore.getBookmarkListener() .subscribe( this::bookmarkChanged ); }

public void bookmarkChanged( Pair<String, Boolean> pair ) { String articleId = pair.first; Boolean newBookmarkValue = pair.second; if( newBookmarkValue ) { getView().addBookmark( articleId ); } else { getView().removeBookmark( articleId ); } }

Context Stores

Repositories

Business Use Cases

Presenters

Today’s subjects

@lojanda

Questions?Architecture https://8thlight.com/blog/uncle-bob/2012/08/13/the-clean-architecture.html

Static datahttp://blog.danlew.net/2015/06/22/loading-data-from-multiple-sources-with-rxjava/

Mutable data http://reactivex.io/RxJava/javadoc/rx/subjects/BehaviorSubject.html

http://reactivex.io/RxJava/javadoc/rx/subjects/PublishSubject.html

https://lorentzos.com/rxjava-as-event-bus-the-right-way-10a36bdd49ba

@lojanda

Architecture and RxJava

Technology