Basic Custom Akka Supervisor in Java
I'm trying to implement jobs with retry semantics using Akka. If a worker fails (throws an exception) during its job, in addition to restarting it I want to resubmit the job it was working on.
The approach I'm trying is a custom supervisor, but I can't get it to restart the worker on failure. e.g. Run the following code with Akka 1.1.3, and you'll never see the restart messages:
import akka.actor.ActorRef;
开发者_如何学编程import akka.actor.UntypedActor;
import akka.actor.UntypedActorFactory;
import akka.config.Supervision;
import static akka.actor.Actors.actorOf;
import static java.lang.System.out;
public class Supervisor extends UntypedActor {
private ActorRef worker;
public static class Worker extends UntypedActor {
@Override
public void onReceive(Object message) {
throw new RuntimeException("croak");
}
public void preRestart(Object reason) {
out.println("supervisor is restarting me!");
}
public void postRestart(Object reason) {
out.println("supervisor restarted me.");
}
}
public static void main(String[] args) {
ActorRef supervisor = actorOf(new UntypedActorFactory() {
public UntypedActor create() {
return new Supervisor();
}
});
supervisor.start();
supervisor.sendOneWay("job");
}
@Override
public void preStart() {
getContext().setFaultHandler(new Supervision.OneForOneStrategy(
new Class[]{RuntimeException.class},
3,
1000
));
// why doesn't the compiler like this line?
// worker = actorOf(Worker.class);
worker = actorOf(new UntypedActorFactory() {
public UntypedActor create() {
return new Worker();
}
});
getContext().startLink(worker);
}
@Override
public void onReceive(Object message) {
worker.sendOneWay(message);
}
}
Any idea what I'm doing wrong?
Thanks!
These are the correct signatures for restart methods in Worker
actor:
@Override
public void preRestart(Throwable reason) {
out.println("supervisor is restarting me!");
}
@Override
public void postRestart(Throwable reason) {
out.println("supervisor restarted me.");
}
And I'm not getting any compilation error for the commented-out line.
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