当他们的构造函数参数被依赖注入时如何实例化子演员？

Question

我正在使用 Playframework，而且我是 Akka 世界的新手。我正在尝试从父演员创建一个子演员。子actor依赖于通过guice注入的服务。我无法弄清楚如何实例化这个子actor。

    class ParentActor extends UntypedActor{

        public static Props props = Props.create(ParentActor.class);

        @Override
        public void preStart() throws Exception{
          // The call here fails. I don't know how i should be creating the child actor 
          childActor = getContext().actorOf(childActor.props);
          childActor.tell(Protocol.RUN, self());
        }

        public void onReceive(Object msg) throws Exception {
           if (msg == AggregateProtocol.DONE){
              sender().tell(Protocol.RUN, self());
           }
        } 

    }

    class ChildActor extends UntypedActor{

       private ServiceA serviceA;

       public static Props props = Props.create(ChildActor.class);

       @Inject
       public ChildActor(ServiceA serviceA){
           this.serviceA = serviceA
       }

        public void onReceive(Object msg) throws Exception {
           if (msg == Protocol.RUN){
              serviceA.doWork();
              sender().tell(Protocol.DONE, self());
           }
        } 

   }

注意：我还尝试了使用工厂和辅助注入的方法，如 Play Java akka 文档中所述。

我如何让这个东西工作？我也看过 IndirectProducer 和 Creator 方法，但我无法很好地理解文档。

Answer 1

您可以将服务注入到父actor中并将其传递给每个子actor。

只有父actor使用Guice依赖注入：

class ParentActor extends UntypedActor{

    private ServiceA serviceA;

    @Inject
    public ParentActor(ServiceA serviceA) {
      this.serviceA = serviceA;
    }

    @Override
    public void preStart() throws Exception{
      // Here pass the reference to serviceA to the child actor
      childActor = Akka.system().actorOf(ChildActor.props(serviceA);
      childActor.tell(Protocol.RUN, self());
    }

    public void onReceive(Object msg) throws Exception {
       if (msg == AggregateProtocol.DONE){
          sender().tell(Protocol.RUN, self());
       }
    } 

}

子actor像往常一样使用 props 方法创建。

class ChildActor extends UntypedActor{

   private ServiceA serviceA;

   public static Props props(ServiceA serviceA) {
     return Props.create(ChildActor.class, serviceA);
   }

   // No inject here
   public ChildActor(ServiceA serviceA){
       this.serviceA = serviceA
   }

   public void onReceive(Object msg) throws Exception {
      if (msg == Protocol.RUN){
          serviceA.doWork();
          sender().tell(Protocol.DONE, self());
      }
   } 

}

可能有更好的方法直接将依赖注入到子actor中。