truemped / hazelcast-actor

Implementation of the actor model in Java using Hazelcast

What

This project is a simple library implementing the actor model for concurrant programming. Using Hazelcast for the message passing allows a very simple scaling of the actors accross multiple nodes.

How

A simple echo actor

final class EchoActor extends AbstractActor<String, String> {

    public EchoActor() {
        super(new DefaultNamingStrategy(), EchoActor.class, true);
    }

    @Override public String call(String input)
    {
        return input;
    }
}

The actor worker

Occasionally you need to scale your actor, i.e. run the same actor with multiple threads. For this you can use the ActorWorker and a corresponding factory to run the actor inside an ExecutorService.

private class EchoActor extends AbstractActorWorker<String, String> {

    protected EchoActor(InputMessage<String> inputMsg, ITopic<OutputMessage<String>> topic) {
        super(inputMsg, topic);
    }

    @Override
    public String call(String input) {
        return input;
    }

}

class EchoActorFactory implements ActorWorkerFactory<String, String> {

    @Override
    public Class<? extends AbstractActorWorker<String, String>> getClazz() {
        return EchoActor.class;
    }

    @Override
    public AbstractActorWorker<String, String> newInstance(InputMessage<String> input, ITopic<OutputMessage<String>> topic) {
        return new EchoActor(input, topic);
    }

}

In order to instantiate the actor you could then do something like this:

ActorManager<String, String> echoManager = new ActorManager<String, String>(new DefaultNamingStrategy(), new EchoActorFactory());
Thread manager = new Thread(echoManager);
manager.start();

And directors

DirectorImpl<String, String> echoProxy = new DirectorImpl<String, String>(new DefaultNamingStrategy(), EchoActor.class);
Future<String> future = echoProxy.call("Test");

Or you can call the same actor with a list of strings and you will get a list of futures (wow, multiple futures...)

List<Future<String>> futures;
List<String> strings = new ArrayList<String>() {
    private static final long serialVersionUID = 7328631044879958719L;
    {
        this.add("Test1");
        this.add("Test2");
    }
};

futures = echoProxy.call(strings);

Notes

Actually I am not really sure if it is appropriate to run the actor within an ExecutorService but this is the only way I could think of to allow recursive calls, e.g. Maybe someone else will guide me to the right path!?

hazelcast-actor's Issues

create a better actor proxy

Create a nicer instantiation of ActorProxies

Possible Memory Leak when multiple Directors call the same Actor

When multiple directors call the same actor they all collect the resulting messages. Fix this by only saving the msg for the calling director.