如何在Akka Actor中实现receive（） [英] How to implement receive () in Akka Actor

问题描述

我正在将Java代码中的Akka UntypedActors转换为它们的Scala等效项。

I am in the process of converting Akka UntypedActors in Java code to their Scala equivalent.

但是，我在理解如何正确实现receive（）时遇到麻烦抽象方法。 ScalaDoc有点令人困惑，我看到的大多数示例都只涉及字符串消息！

However, I am having trouble understanding how to correctly implement the receive() abstract method. The ScalaDoc is a little confusing and most of the examples I see just involve String messages!

我的Actor可以支持多种消息类型，到目前为止，这是我的解决方案：

My Actor can support multiple message types and this is my solution so far:

override def receive = {
    case message if message.isInstanceOf[ClassOne] => {
        // do something after message.asInstanceOf[ClassOne]
      }
    case message if message.isInstanceOf[ClassTwo] => {
      // do something after message.asInstanceOf[ClassTwo]
    }        
    case message => unhandled(message)
  }

是否有更好的方法来实现上述目标？

Is there a better way to achieve the above?

推荐答案

接收的类型实际上只是一个 PartialFunction [Any，Unit] ，，这意味着您可以使用Scala的模式匹配表达式-实际上，您已经在这么做了，只是不完全简洁。等效的简短处理也可以让您处理每种情况的匹配类型：

receive's type is really just a PartialFunction[Any,Unit], which means you can use Scala's pattern match expressions - in fact, you're already doing it, just not entirely succinctly. A terser equivalent that would also let you handle the type of the match for each case:

def receive = {
    case classOneMessage : ClassOne => {
        // do something
      }
    case classTwoMessage : ClassTwo => {
      // do something 
    }        
    case _ => someCustomLogicHereOtherWiseThereWillBeASilentFailure 
              //you can, but you don't really need to define this case - in Akka 
              //the standard way to go if you want to process unknown messages
              //within *this* actor, is to override the Actor#unhandled(Any) 
              //method instead
  }

阅读旅游文章 ，以及已链接的教程以了解更多信息模式匹配的信息，尤其是在将功能与案例类一起使用的情况下-在使用Akka时会定期应用此模式，例如此处位于Akka手册中处理 ActorIdentity 案例类。

Read the tour article, and the already-linked tutorial for more info on pattern matching, especially in the context of using the feature together with case classes - this pattern is applied regularly when working with Akka, for example here in the Akka manual when handling the ActorIdentity case class.

这篇关于如何在Akka Actor中实现receive（）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！