Invalidation factory for javafx.beans.Observable

[protogenes]

Add a factory for invalidations of any FX observable.
I think propagating the FX observable instead of some constant is of better value.

public static Observable<javafx.beans.Observable> invalidationsOf(final javafx.beans.Observable fxObservable) {
    return ObservableSource.fromInvalidations(fxObservable);
}

public class ObservableSource {
	private ObservableSource() {}

	public static Observable<javafx.beans.Observable> fromInvalidations(javafx.beans.Observable fxObservable) {
		return Observable.create((ObservableEmitter<javafx.beans.Observable> emitter) -> {
			final InvalidationListener listener = emitter::onNext;
			fxObservable.addListener(listener);
			emitter.setDisposable(JavaFxSubscriptions.unsubscribeInEventDispatchThread(() -> fxObservable.removeListener(listener)));
		});
	}
}

[thomasnield]

Makes perfect sense. I'll implement this later in 1.0 as well as the 2.0 branch.

[thomasnield]

Wouldn't it make more sense to emit an ObservableValue<T> rather than just a JavaFX Observable? The JavaFX Observable (not Rx one) does not have the getValue() method, but the ObservableValue<T> does. I imagine that would be more useful.

    public static <T> Observable<ObservableValue<T>> fromInvalidations(final ObservableValue<T> fxObservable) {
        return Observable.create(subscriber -> {
            final InvalidationListener listener = s -> subscriber.onNext(fxObservable);
            fxObservable.addListener(listener);
            subscriber.add(JavaFxSubscriptions.unsubscribeInEventDispatchThread(() -> fxObservable.removeListener(listener)));
        });
    }

Would it also make sense to overload a Property<T> version as well? That way we can have access to a setValue() method for each emitted Property<T>?

    public static <T> Observable<Property<T>> fromInvalidations(final Property<T> fxProperty) {
        return Observable.create(subscriber -> {
            final InvalidationListener listener = s -> subscriber.onNext(fxProperty);
            fxProperty.addListener(listener);
            subscriber.add(JavaFxSubscriptions.unsubscribeInEventDispatchThread(() -> fxProperty.removeListener(listener)));
        });
    }

[protogenes]

The main difference is, that ObservableList<>, ObservableSet<>, ObservableMap<> and Property<> all implement the Observable interface and this could be used without knowing the specific type. If you know it you should use valuesOf, changesOf and so on.

[thomasnield]

@protogenes that makes sense. Okay I'll implement your way.

[thomasnield]

@protogenes Implemented in 1.x. I'll do 2.x as soon as I merge the new Scheduler for that branch. Let me know if that's ready.