Question

我想在Akka演员处理PoisonPill时完成未来。

我试过了：

someRef？ PoisonPill

但这永远不会完成。我想你只能用'！'并不是 '？'。有什么想法吗？

Answer 1

如果您想要监视某个子actor的生命周期，您只需watch该actor并根据您的逻辑处理Terminated消息。例如：

class MyActor extends Actor {

  import context._ // to avoid writing context everywhere

  val child = actorOf(Props(new ChildActor)) // ChildActor is the type of the actor you are monitoring, the child
  watch(child) // subscribe to the Terminated message of the child

  override def receive: Receive = {
    case "kill" ⇒ child ! PoisonPill // kill the child. You could also use context.stop(child)
    case Terminated(`child`) ⇒ println("child died") // handle the termination of the child. Use back-ticks to make child a stable identifier
    case _ ⇒ println("meh") // who cares
  }
}

现在，如果你想要一个明确的Future，我想到的第一件事就是将Promise传递给你想要观看的演员，并覆盖postStop来完成诺言。它看起来像这样：

class MyActor(p: Promise[Unit]) extends Actor { // receive the Promise to complete

  override def receive: Receive = {
    case _ ⇒ println("meh") // who cares
  }

  override def postStop(): Unit = { // after stopped
    p.tryComplete(Success(())) // complete the promise
  }
}

object Main {
  def main(args: Array[String]) {
    val system = ActorSystem("test")
    val p = Promise[Unit]()
    val f = p.future // get the future from the promise
    val a = system.actorOf(Props(new MyActor(p))) // send the promise to the actor you want to watch

    f onSuccess { // register a callback when the future completes
      case _ ⇒ println("actor died")
    }

    a ! "foo"
    a ! PoisonPill
  }
}

希望它有所帮助。干杯！

Akka确保毒丸消耗殆尽

1 个答案: