Actor - Become/Unbecome

class HotSwapActor extends Actor {

  import context._

  def angry: Receive = {
    case "foo" => sender() ! "I am already angry?"
    case "bar" => become(happy)
    case "ex" => throw new Exception("exception here")
    case _ => println("angry")
  }

  def happy: Receive = {
    case "bar" => sender() ! "I am already happy :-)"
    case "foo" => become(angry)
    case _ => println("happy")
  }

  def receive = {
    case "foo" => become(angry)
    case "bar" => become(happy)
    case _ => println("default")
  }
}

become是对消息处理集合的动态切换.
当actor restart的时候 状态恢复初始状态

val swap = system.actorOf(Props[HotSwapActor], "swap")

  swap ! "xxx"
  swap ! "foo"
  swap ! "xxx"
  swap ! "ex"
  swap ! "xxx"
  swap ! "bar"
  swap ! "xxx"

default
angry
default
happy

unbecome就不介绍了,感觉一般用不上.还容易搞出内存泄漏