Modern Akka DI with Guice

Question

Java 8, Guice 4.0 and Akka 2.3.9 here. I am trying to figure out how to annotate my actor classes with JSR330-style @Inject annotations, and then wire them all up v

Answer 1

Generic Akka Guice integration without dependency on Play, keeping in mind, not the only actor should be created in the actor system.

import akka.actor.Actor;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import com.google.inject.AbstractModule;
import com.google.inject.Provider;
import com.google.inject.name.Names;

public abstract class AkkaGuiceModule extends AbstractModule {

    protected  void bindActor(Class actorClass, String name) {
        bind(actorClass);

        Provider actorSystemProvider = getProvider(ActorSystem.class);
        Provider actorProvider = getProvider(actorClass);

        bind(ActorRef.class)
                .annotatedWith(Names.named(name))
                .toProvider(ActorRefProvider.of(actorSystemProvider, actorProvider, name))
                .asEagerSingleton();
    }

}

Generic ActorRefProvider to create ActorRef for each Actor

import akka.actor.Actor;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.actor.Props;
import akka.japi.Creator;
import com.google.inject.Provider;
import lombok.Value;

@Value(staticConstructor = "of")
public class ActorRefProvider implements Provider {

    private Provider actorSystemProvider;
    private Provider actorProvider;
    private String name;

    public final class ActorCreator implements Creator {
        @Override
        public Actor create() {
            return actorProvider.get();
        }
    }

    @Override
    public ActorRef get() {
        return actorSystemProvider.get().actorOf(Props.create(new ActorCreator()), name);
    }

}

Usage example

import akka.actor.ActorSystem;
import com.google.inject.Provides;
import com.typesafe.config.Config; // optional

public class MyAkkaModule extends AkkaGuiceModule {

    @Provides
    @Singleton
    ActorSystem actorSystem(Config config) {
        return ActorSystem.create("actor-system-name", config);
    }

    @Override
    protected void configure() {
        bindActor(SomeActor1.class, "actorName1");
        bindActor(SomeActor2.class, "actorName2");
    }

}