Akka演员消息序列

Question

I have the following actor structure

import akka.actor.ActorRef;
import akka.actor.UntypedActor;

public class ExampleActor extends UntypedActor {
    ActorRef worker1;
    ActorRef worker2;

    @Override
public void onReceive(Object msg) throws Exception {


    if (msg instanceof PerformTask) {

        worker1.tell(doTask1, getSelf());
        worker2.tell(doTask2, getSelf());

        // Perform some task with the results of the above two calls

    }
}

}

import akka.actor.UntypedActor;

public class Worker1 extends UntypedActor {

    @Override
    public void onReceive(Object msg) throws Exception {

        if (msg instanceof doTask1) {
            return result1;
        }

    }

}

Worker 2

import akka.actor.UntypedActor;

public class Worker2 extends UntypedActor {

    @Override
    public void onReceive(Object msg) throws Exception {

        if (msg instanceof doTask2) {
            return result2;
        }

    }

}

How do I make sure that result 1 and result 2 are obtained before ExampleActor performs its own task?

If I have separate messages for receieving the response in exampleActor, how do I pass this response to "PefrformTask" action?

Answer 1

You need to start building a state in your ExampleActor . When you receive any of the two responses you are waiting for from your Workers , you need save that response. Either the message, or just the relevant content of it. Something like:

if (msg instanceof WorkerTaskResult) {
    results.add((WorkerTaskResult)msg);
}
if(results.size() == number_of_results_expected) {
    //perform whatever I wanted to do on those results from workers
}

results is of course non-static field on your ExampleActor .

Note:
This example above is super-simplistic just to give you the idea about the solution. There are many things to watch out for: ExampleActor restarted / Workers not producing results, etc.