I'm looking for a coroutine equivalent of Countdow...

# coroutines

[David Glasser]

I'm looking for a coroutine equivalent of CountdownLatch (even just for the most basic n=1 case) where one coroutine can block until another coroutine says it can go. What am I looking for?

[octylFractal]

for n=1, I think mutex is sufficient

[octylFractal]

there's also Semaphore but it doesn't work as a CoutdownLatch

[David Glasser]

thanks, that sounds good.

[David Glasser]

esp since they can start pre-locked 🙂

[octylFractal]

I made a quick + dirty implementation https://gist.github.com/octylFractal/fd86b67bbdbf61f02c853142aced0534

[octylFractal]

the trick with coroutines is implementing these sorts of concurrency classes is much easier 🙂

[Dominaezzz]

I direct equivalent is a CompletableDeferred. Okay... Somewhat direct. If n =1.

[David Glasser]

@octylFractal I dunno that MutableSet is thread-safe?

[octylFractal]

well, I did say it was quick and dirty :P you can likely replace it with CopyOnWriteArraySet for little performance loss

[Evan R.]

Personally I’d use a rendezvous channel to effectively “trigger” the listening coroutine from the controlling coroutine but that’s just my opinion 🙃