scala – 如何处理Akka小孩演员的长初始化？

发布时间：2020-12-16 09:12:36 所属栏目：安全来源：网络整理

导读：我有一个演员,创建一个孩子演员来执行一些冗长的计算. 问题是,子actor的初始化需要几秒钟,并且父actor发送给它之间的子节点的所有消息被创建并被完全初始化. 这是我使用的代码的逻辑： class ChildActor extends Actor { val tagger = IntializeTagger(...)

我有一个演员,创建一个孩子演员来执行一些冗长的计算.

问题是,子actor的初始化需要几秒钟,并且父actor发送给它之间的子节点的所有消息被创建并被完全初始化.

这是我使用的代码的逻辑：

class ChildActor extends Actor {
  val tagger = IntializeTagger(...) // this takes a few seconds to complete

  def receive = {
    case Tag(text) => sender ! tagger.tag(text)
    case "hello" => println("Hello")
    case _ => println("Unknown message")
  }
}

class ParentActor extends Actor {
  val child = context.ActorOf(Props[ChildActor],name = "childactor")

  // the below two messages seem to get lost
  child ! "hello"
  child ! Tag("This is my sample text")

  def receive = {
     ...
  }
}

我该怎么解决这个问题？是否可以使父级actor等到孩子完全初始化之前？我将使用带有路由的子演员,并可能在远程演员系统上使用.

编辑

按照drexin的建议,我将代码更改为：

class ChildActor extends Actor {
  var tagger: Tagger = _

  override def preStart() = {
    tagger = IntializeTagger(...) // this takes a few seconds to complete
  }

  def receive = {
    case Tag(text) => sender ! tagger.tag(text)
    case "hello" => println("Hello")
    case _ => println("Unknown message")
  }
}

class ParentActor extends Actor {
  var child: ActorRef = _

  override def preStart() = {
    child = context.ActorOf(Props[ChildActor],name = "childactor")

    // When I add
    // Thread.sleep(5000)
    // here messages are processed without problems

    // wihout hardcoding the 5 seconds waiting 
    // the below two messages seem to get lost
    child ! "hello"
    child ! Tag("This is my sample text")
  }

  def receive = {
     ...
  }
}

但问题依然存在.我失踪了什么

解决方法

不要在构造函数中初始化标记器,而是在preStart钩子中,这样,当actor准备就绪时,消息将被收集到消息框中并传递.

编辑：

您应该对ParentActor类中的actor创建执行相同的操作,因为如果ChildActor在ParentActor初始化之前会发生响应,那么您将遇到同样的问题.

EDIT2：

我创建了一个简单的例子,但是我无法重现你的问题.以下代码工作完美：

import akka.actor._

case class Tag(x: String)

class ChildActor extends Actor {
  type Tagger = String => String
  var tagger: Tagger = _

  override def preStart() = {
    tagger = (x: String) => x+"@tagged" // this takes a few seconds to complete
    Thread.sleep(2000) // simulate time taken to initialize Tagger
  }

  def receive = {
    case Tag(text) => sender ! tagger(text)
    case "hello" => println("Hello")
    case _ => println("Unknown message")
  }
}

class ParentActor extends Actor {
  var child: ActorRef = _

  override def preStart() = {
    child = context.actorOf(Props[ChildActor],name = "childactor")

    // When I add
    // Thread.sleep(5000)
    // here messages are processed without problems

    // wihout hardcoding the 5 seconds waiting 
    // the below two messages seem to get lost
    child ! "hello"
    child ! Tag("This is my sample text")
  }

  def receive = {
    case x => println(x)
  }
}

object Main extends App {

  val system = ActorSystem("MySystem")

  system.actorOf(Props[ParentActor])
}

输出为：

[info] Running Main
Hello
This is my sample text@tagged

（编辑：李大同）

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