RxJava PublishSubject+Debounce: the second item not emited

Question

I want to use PublishSubject + debounce (in subscribe logic) for emit my items with delay. This is my code:

Subscription logic:

notificationSubject = PublishSubject.create<Notification>()
notificationSubject
            .debounce(300, TimeUnit.MILLISECONDS)
            .doOnIOSubscribeOnMain() // ext. fun, I hope you understand it
            .subscribe {
                displayNotification(it)
            }

And emit objects logic:

showNotification(obj1)
showNotification(obj2) 
// ...
fun showNotification(notification: Notification) {
    notificationSubject.onNext(notification)
}

But on subscribe I receive only first emitted item (obj1). And if I emit two objects (obj3, obj4) again I receive only first of emitted item (obj3).

How to fix it?

What's your requirement/problem really? debounce is not only for delay but also for filtering "rapid fire", though it would be the latest item that gets emitted, not the first. — laalto, Jul 04 '18 at 07:32
@laalto I check via logs and I receive on subscribe only first emitted item. And is there debounce analogue without "rapid fire" filtering? — Artem, Jul 04 '18 at 07:36
@laalto my requirement: I want to use PublishSubject + debounce (in subscribe logic) for emit my items with delay. — Artem, Jul 04 '18 at 07:36
If you want delay without filtering, use the `delay()` operator. — laalto, Jul 04 '18 at 07:36
@laalto delay cannot to distinct my items by time-intervals. It only delayed my items. — Artem, Jul 04 '18 at 07:38

score 2 · Answer 1 · answered Jul 04 '18 at 09:04

Debounce is a lossy operator that skips items emitted too close to each other. You can't use that for addressing your requirements.

You could zip with an interval instead:

notificationSubject.zipWith(Observable.interval(300, TimeUnit.MILLISECONDS), (a, b) -> a)

RxJava PublishSubject+Debounce: the second item not emited

1 Answers1