No implementation for akka.actor.ActorRef was bound

Question

I'm trying to create an actor in Java Play Framework (2.5.10) for running periodic tasks. When my application runs, however, I get the error No implementation for akka.actor.ActorRef was bound (detailed error messages provided later in this post). I'm sure the mistake is pretty basic, but I'm new to the whole actors thing and am having trouble figuring it out.

Here's the class (root-level Module.java) that binds the scheduler class and the actor:

public class Module extends AbstractModule implements AkkaGuiceSupport {

    @Override
    public void configure() {
        // Use the system clock as the default implementation of Clock
        bind(Clock.class).toInstance(Clock.systemDefaultZone());
        // Ask Guice to create an instance of ApplicationTimer when the
        // application starts.
        bind(ApplicationTimer.class).asEagerSingleton();
        // Set AtomicCounter as the implementation for Counter.
        bind(Counter.class).to(AtomicCounter.class);

        // bind the ECWID data importer
        bind(ImportScheduler.class).asEagerSingleton();
        bindActor(UserImportActor.class, UserImportActor.ACTOR_NAME);
    }
}

The scheduler class:

@Singleton
public class ImportScheduler {

    @Inject
    public ImportScheduler(final ActorSystem actorSystem, final ActorRef UserImportActor) {
        actorSystem.scheduler().schedule(
                Duration.create(1, TimeUnit.SECONDS),
                Duration.create(1, TimeUnit.SECONDS),
                UserImportActor,
              0,
                actorSystem.dispatcher(),
                UserImportActor
            );
    }
}

And finally, the actor class:

public class UserImportActor extends UntypedActor  {
    public static final String ACTOR_NAME = "user_import_actor";

    @Override
    public void onReceive(Object message){
        Logger.info("The user import actor was called!");
    }
}

When the application runs, here's the error that I see (the full error is too long - I think the first few lines will suffice):

! @72bagdfd4 - Internal server error, for (GET) [/] ->

play.api.UnexpectedException: Unexpected exception[CreationException: Unable to create injector, see the following errors:

1) No implementation for akka.actor.ActorRef was bound.
  while locating akka.actor.ActorRef
    for parameter 1 at services.ecwid.db.ImportScheduler.<init>(ImportScheduler.java:12)
  at Module.configure(Module.java:34) (via modules: com.google.inject.util.Modules$OverrideModule -> Module)

Any idea what I'm missing?

Stefano Bonetti Stefano Bonetti · Accepted Answer · 2016-12-10T14:41:08

The bindActor method annotates your ActorRef with a name - the name of the actorRef itself.

Could you try using the @Named annotation?

    @Inject
    public ImportScheduler(final ActorSystem actorSystem, @Named("user_import_actor") ActorRef UserImportActor) {
        ...
    }

No implementation for akka.actor.ActorRef was bound

1 Answers