Does reaktive have some sort of ObservableList? I ...

# reaktive

[martmists]

Does reaktive have some sort of ObservableList? I can find Observable which returns items as it receives them, but the toList states it only works on finite observables. What do I do to get a snapshot state of an infinite observable? (and/or is there a way to clear elements from an observable?) Or is there a different class I should be looking at?

[Arkadii Ivanov]

Reaktive resembles RxJava and implements Reactive Extensions. There is no such a thing as "snapshot state" of an Observable. And there is no way of "clearing elements" from an Observable. What's your use case?

[martmists]

My use case is having a collection that emits updates to any active or new flows. This would allow the following operations:
• Fetch the collection as of right now
• Clear the collection
• Get a Flow of all elements in the collection, then suspend until a new element is added and emit it to the flow, and suspend again.

[martmists]

The current use-case is live metrics for a website (e.g. Exceptions that occurred), but I can imagine there being a good amount of other use-cases for a setup like this.

[Arkadii Ivanov]

I think in this case you can use BehaviorSubject<List<T>> and expose it as BehaviorSubject<List<T>>. This would allow clients to subscribe for list updates and read the current state if needed. Also you can add clear() method to clear the list (i.e. subject.onNext(emptyList()).

[martmists]

How would that work? I'm not quite sure how mutating a list would inform the BehaviorSubject to emit updates. And considering the size of these lists, I can't afford to create a new list every time I need to add an element.

[Arkadii Ivanov]

How big is the list?