Akka Actor如何仅处理最新消息 [英] Akka Actor how to only process the latest message

问题描述

说我正在向Actor发送消息，当它正在处理一条消息时，可能还会出现更多消息。现在，当准备处理下一条消息时，我希望它仅处理最新的消息，因为先前的消息已过时。我怎样才能最好地做到这一点？

Say I am sending messages to an Actor, when it is processing one message several more messages may arise. Now when it is ready to process the next message I want it to only process the latest message as the previous ones have become obsolete. How can I best achieve this?

使用scala Actors库，首先可以从发件人处进行检查，如下所示：

Using the scala Actors library I was able to achieve this by first checking from my sender as follows:

if (myActor.getState != Runnable)
  myActor ! message     

但是我不认为我可以在Akka系统中进行这样的测试

But I don't think I can do such a test in the Akka system

推荐答案

无需实现自己的邮箱。

There is no need to implement your own mailbox. At all.

删除了大量文本，并让这段代码说明一切：

Removed a lot of text and let this piece of code speak for itself:

// Either implement "equals" so that every job is unique (by default) or do another comparison in the match.
class Work 
case class DoWork(work: Work)

class WorkerActor extends Actor {
  // Left as an exercise for the reader, it clearly should do some work.
  def perform(work: Work): Unit = ()

  def lookingForWork: Receive = {
    case w: Work =>
      self forward DoWork(w)
      context become prepareToDoWork(w)
  }

  def prepareToDoWork(work: Work): Receive = {
    case DoWork(`work`) =>
      // No new work, so perform this one
      perform(work)
      // Now we're ready to look for new work
      context become lookingForWork
    case DoWork(_) =>
      // Discard work that we don't need to do anymore
    case w2: Work =>
      // Prepare to do this newer work instead
      context become prepareToDoWork(w2) 
  }

  //We start out as looking for work
  def receive = lookingForWork
}

这意味着仅当没有更新时才执行工作在邮箱中工作。

This means that work will only be performed if there is no newer work in the mailbox.

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