Question

我有一个有几个孩子的Akka父母演员。当重新启动父actor时，我需要它来简单地停止它的子节点，而不是停止并重新创建或重新启动它们。（如果需要，孩子将在以后手动创建。）有没有办法做到这一点？也许以某种方式覆盖父母的preRestart方法？

Answer 1

默认情况下Actor在重启时处理它的子节点。这是Actor.preRestart代码：

  /**
   * User overridable callback: '''By default it disposes of all children and then calls `postStop()`.'''
   * @param reason the Throwable that caused the restart to happen
   * @param message optionally the current message the actor processed when failing, if applicable
   * <p/>
   * Is called on a crashed Actor right BEFORE it is restarted to allow clean
   * up of resources before Actor is terminated.
   */
  @throws(classOf[Exception]) // when changing this you MUST also change UntypedActorDocTest
  //#lifecycle-hooks
  def preRestart(reason: Throwable, message: Option[Any]): Unit = {
    context.children foreach { child ⇒
      context.unwatch(child)
      context.stop(child)
    }
    postStop()
  }

正如您所见，父母会停下来并且不看其孩子。你可以像这样覆盖它，让一个演员让孩子们活着：

override def preRestart(reason: Throwable, message: Option[Any]): Unit = ()

因此，出于您的目的，您无需覆盖preRestart，您将获得所需的行为。如果您想要更多自定义行为，例如在启动时启动子项而不是在重新启动事件上，则可以查看其他回调。

如何在父母重新开始时仅停止儿童演员？

1 个答案: