Solution for "UntypedActor" deprecated in Akka (Java) Tutorial

Question

Original Code

Akka tutorial has the following code: http://doc.akka.io/docs/akka/2.0.2/intro/getting-started-first-java.html

public void calculate (final int nrOfWorkers, final int nrOfElements, final int nrOfMessages){
    ActorSystem system = ActorSystem.create("PiSystem");
    final ActorRef listener = system.actorOf(Props.create(Listener.class), "listener");
    ActorRef master = system.actorOf(new Props(new UntypedActorFactory() {
            public UntypedActor create() {
                return new Master(nrOfWorkers, nrOfMessages, nrOfElements, listener);
            }
    }), "master");
    master.tell(new Calculate(), ActorRef.noSender());
}

in which, UntypedActorFactory is deprecated.

My Mod

So I tried to use Props.create such as

ActorRef master = system.actorOf( Props.create(
            new Creator<Master>(){
                public Master create(){
                    return new Master(nrOfWorkers, nrOfMessages, nrOfElements, listener);
            }
    }), "master");

And there is Exception saying

cannot use non-static local Creator to create actors; make it static or top-level

so I start to write a static class, which has parameters needed to be passed.

static class LocalCreator implements Creator<Master>{
    public Master create(){
        return new Master(nrOfWorkers, nrOfMessages, nrOfElements, listener);
    }
}

Question

How to pass the parameters nrOfWorkers and etc. into the create() function elegantly?

Answer 1

If you read the Akka docs (Java flavor), it lists two ways you can construct an actor that has constructor params. The first is like so (using your example classes):

ActorSystem system = ActorSystem.create("PiSystem");
final ActorRef listener = system.actorOf(Props.create(Listener.class), "listener");
ActorRef master = system.actorOf(Props.create(Master.class, nrOfWorkers, nrOfMessages, nrOfElements, listener), "master");
master.tell(new Calculate(), ActorRef.noSender());

Or if you don't want to go that route, you can use a Creator like so:

public class MasterCreator implements Creator<Master>{
  private int nrOfWorkers, nrOfMessages, nrOfElements;
  private ActorRef listener;
  public MasterCreator(int nrOfWorkers, int nrOfMessages, int nrOfElements, ActorRef listener){
    this.listener = listener;
    this.nrOfElements = nrOfElements;
    this.nrOfMessages = nrOfMessages;
    this.nrOfWorkers = nrOfWorkers;
  }

  public Master create(){
    return new Master(nrOfWorkers, nrOfMessages, nrOfElements, listener);
  }
}

And then use it like this:

  ActorSystem system = ActorSystem.create("PiSystem");
  final ActorRef listener = system.actorOf(Props.create(Listener.class), "listener");
  ActorRef master = system.actorOf(Props.create(new MasterCreator(nrOfWorkers, nrOfMessages, nrOfElements, listener)), "master");
  master.tell(new Calculate(), ActorRef.noSender());