I need a `PublishSubject` alternative as flow The closest representation I found is a `Channel RENDEZVOUS ` However the `consumeAsFlow` function states gt If the flow consumer fails with an exception channel is cancelled I don t want that Is there an alternative for that

That creates an implicit contract on the flow consumer, it only want to expose the flow without the consumers having the possibility to cancel the underlying implementation

louiscad

10/08/2019, 9:47 AM

The solution might be to use a

BroadcastChannel

(or the

broadcast

operator I think). Beware of not leaking hot resources!

Luis Munoz

10/08/2019, 3:53 PM

@Paul Woitaschek can you elaborate on what you mean by "that creates an implicit contract on the flow" and why you want to void that?

Paul Woitaschek

10/08/2019, 4:16 PM

Lets say I have a view model where I want to propagate one time events without a buffer (so that if no one is observing the flow, the values don’t get delivered later):

class ViewModel {
  private val _events = Channel<Event>(RENDEZVOUS)
  val events : Flow<Event> get() = _events.consumeAsFlow()
}

Now I don’t want the

_events

channel to close permanently because a consumer threw an exception in it’s collect function. So now there is this implicit contract: Don’t throw an exception or the channel is broken and there will be no more events

Luis Munoz

10/08/2019, 4:46 PM

makes sense thank you

@Paul Woitaschek think of this... If I were you I would you just create wrapper around the consumer that catches exceptions. Instead of doing collect(), you do collectWithExceptionhandler( consumercode: () -> Unit, errorHandler)

then you know collect will enver throw exception

Paul Woitaschek

10/08/2019, 9:03 PM

Hm that feels like a hack. @elizarov Is there a better solution?

elizarov

10/08/2019, 9:25 PM

Like this one: https://github.com/Kotlin/kotlinx.coroutines/issues/1490

👍 1

Paul Woitaschek

10/09/2019, 4:55 AM

Absolutely. Does the last implementation miss something?

4 Views

#coroutines Join Slack