How to put actor to sleep?

Question

I have one actor which is executing a forever loop that is waiting for the availability of data to operate on. The doc says the Actor runs on a very lightweight thread, so I'm not sure whether i can use the thread.sleep() method on that actor. My objective is to not have that actor consume too much processing power.

So can I use the thread.sleep() method inside the actor ?

Gunner

aah got it. Better to keep on passing command to that actor. – Gunner

Answer 1

Don't sleep() inside Actors! That would cause the Thread to be blocked, causing exactly what you're trying to avoid - using up resources.

Instead if you just handle the message and "do nothing", the Actor will not use up any scheduling resources and will be just another plain object on the heap (occupying around a bit of memory but nothing else).

Hewlett

I'd like to add that to keep on handling that message and do nothing, i have to use UntypedActor so i could use the self method. Before this i use TypedActor. – Gunner

If by "keep on handling that message" you mean keep working on it, you can start a Future that encapsulates that work, and put it on a different dispatcher, so that it does not use up the actor's dispatcher resources. TypedActors are discouraged in any case as they're 10x slower than untyped ones (related, we are working on akka-typed which solves this doc.akka.io/docs/akka/snapshot/scala/typed.html ) – Plat

Answer 2

I just schedule to send a "WakeUp" message in a future time. Akka will send that message at predefined time, so the actor can handle and continue processing. This is to avoid using sleep.

        // schedule to wake up
        getContext().getSystem().scheduler().scheduleOnce(
            FiniteDuration.create(sleepTime.toMillis(), TimeUnit.MILLISECONDS),
            new Runnable() {
              @Override
              public void run() {
                getContext().getSelf().tell(new WakeUpMessage());
              }
            },
            getContext().getSystem().executionContext());

Put