Scala案例类在receive方法中不匹配(在akka actor中)

发布时间：2020-12-16 09:51:16 所属栏目：安全来源：网络整理

导读：我有这样的事情： class ProbeActor extends Actor { case class Probe(messageKey: String) def receiveProbe: Receive = { case Probe(probeKey) = println("Good probe: "+probeKey) case x = println("Bad probe: "+ x) } final override def receive =

我有这样的事情：

class ProbeActor extends Actor {
  case class Probe(messageKey: String)
  def receiveProbe: Receive = {
    case Probe(probeKey) => println("Good probe: "+probeKey)
    case x => println("Bad probe: "+ x)
  }
  final override def receive = receiveProbe orElse receiveOther
  def receiveOther: Receive = {
    case _ => println("Other")
  }
}

我称之为：

class Prober extends ProbeActor {
  val definite = ActorSystem("ProbeTest").actorOf(Props[ProbeActor],name = "probed")
  implicit val timeout = Timeout(5 second)
  val future = definite ? Probe("key")
}

我希望打印文本“Good probe：key”,但我得到“Bad probe：Probe(key)”.

注意：如果我将Probe案例类放在外面,那么它可以正常工作.

解决方法

经过更多搜索,我在 scala-lang.org找到了答案：

I think the underlying misconception is about the identity of nested
class types.

In

class A { class B }

each new instance of class A x creates a new type x.B. And if you do the plain pattern match inside of A you are referring to the specific instance of the type B this.B.

（编辑：李大同）

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