StateSubject: A Java repository from esafirm

StateSubject

Imitate LiveData behaviour, using RxJava's Subject.

Gradle

repositories {
    jcenter()
}
dependencies {
    implementation 'nolambda.stream:statesubject:1.0.0'
}

Usage

Simply change observe keyword, with subscribe

Simple

StateSubject<Integer> subject = new StateSubject()
subject.subscribe(lifecycleOwner, { item ->
    // 1 and then 2
})
subject.postValue(1)
subject.postValue(2)

Disposing observer a.k.a removing observer in LiveData

Removing observer is easy, rather than using removeObserver() like LiveData, StateSubject return Disposable in every subscribe event.

Disposable dispoasble = subject.subscribe(lifecycleOwner, this::renderData);
if(!dispoasble.isDisposed()){
    dispoasble.dispose();
}

Manipulate Stream

Since it use RxJava Subject, manipulating stream is as easy as passing ObservableTransformer.

StateSubject<String> subject = new StateSubject();
subject.subscribe(lifecycleOwner, s -> s.map(s -> s + "!"), s -> {
    // Will trigger J! K! T! in sequence
})
subject.postValue("J");
subject.postValue("K");
subject.postValue("T");

Extending StateSubject

Just replace extends LiveData<> with extends StateSubject<>

public class StockLiveData extends StateSubject<BigDecimal> {
    private StockManager stockManager;

    private SimplePriceListener listener = new SimplePriceListener() {
        @Override
        public void onPriceChanged(BigDecimal price) {
            setValue(price);
        }
    };

    public StockLiveData(String symbol) {
        stockManager = new StockManager(symbol);
    }

    @Override
    protected void onActive() {
        stockManager.requestPriceUpdates(listener);
    }

    @Override
    protected void onInactive() {
        stockManager.removeUpdates(listener);
    }
}

Full parameters of subscribe()

@NonNull
public Disposable subscribe(@NonNull LifecycleOwner owner,
                            @Nullable ObservableTransformer<T, T> transformer,
                            @NonNull final Scheduler subscribeScheduler,
                            @NonNull final Scheduler observeScheduler,
                            @NonNull final Consumer<T> consumer)

More Samples

You can jump to sample module or test files

What's Next

Add Immutable variant

License

MIT @ Esa Firman

esafirm/StateSubject