CODEWITHSUNDEEP
javaakkaactor-model
FrankTan
FrankTan

Reputation: 1686

Akka difference between actorSelection and resolveActorRef

i m using two different ways for get the same result but at one i need to specify a call back time why ? Them dose the same things ?

    ActorRef resolveActorRef = getContext().getSystem()
                .provider() .resolveActorRef(ActorPath.fromString("akka://RootRemoteActors/user/$a/remote.actors.AA"));

The code above retrive an actor Ref without waiting any time Why if i do not get the proveider i have to specify a time duration?

      ActorSelection actorSelection = getContext().getSystem()
            .actorSelection( ActorPath.fromString("akka://RootRemoteActors/user/$a/remote.actors.AA"));



       ActorRef ois = actorSelection.resolveOne( new Timeout(1000, TimeUnit.MILLISECONDS  ))
                .value().get().get();

Upvotes: 1

Views: 785

Answers (1)

thwiegan
thwiegan

Reputation: 2173

The most obvious difference is probably that an ActorSelection can represent multiple ActorRefs if you use wildcards in the actor path. So if you just call .tell on your actorSelection instead of resolveOne you deliver the message to all matching actors.

I never used resolveActorRef but from what I can see from the sources (ActorRefProvider and ActorSelection) ActorRefProvider uses getChild on the rootGuardian to find that Actor you are looking for and therefore traverses from the top of your actor tree down until he finds it eventually (or not).

ActorSelection tries to send an Identify message using the ask-pattern (therefore the timeout) to the selection and if it receives a response it will provide the ActorRef from which it got the response.

resolveActorRef seems to be used if you write your own serializer: Akka Docs, so if you just want to resolve an actor, I would go with the ActorSelection (which you btw. don't have to resolve in order to send a message to it).

Upvotes: 1

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