在Akka接收方法中在Scala中组合特征行为
在Akka接收方法中在Scala中组合特征行为
提问于 2011-12-31 00:11:32
考虑以下两个特征：
trait Poked extends Actor {
override def receive = {
case Poke(port, x) => ReceivePoke(port, x)
}
def ReceivePoke(port: String, x: Any)
}
trait Peeked extends Actor {
override def receive = {
case Peek(port) => ReceivePeek(port)
}
def ReceivePeek(port: String)
}现在考虑我可以创建一个新的Actor来实现这两个特征：
val peekedpoked = actorRef(new Actor extends Poked with Peeked)如何编写接收处理程序？也就是说，接收器应该类似于下面的代码，尽管是“自动生成的”(即所有特征都应该组合在一起)：
def receive = (Poked.receive: Receive) orElse (Peeked.receive: Receive) orElse ...回答 2
Stack Overflow用户
回答已采纳
发布于 2011-12-31 03:53:18
您可以使用super[T]来引用特定超类/特征的成员。
例如：
trait IntActor extends Actor {
def receive = {
case i: Int => println("Int!")
}
}
trait StringActor extends Actor {
def receive = {
case s: String => println("String!")
}
}
class IntOrString extends Actor with IntActor with StringActor {
override def receive = super[IntActor].receive orElse super[StringActor].receive
}
val a = actorOf[IntOrString].start
a ! 5 //prints Int!
a ! "Hello" //prints String!编辑：
为了回应Hugo的评论，这里有一个解决方案，允许您在不必手动连接它们的接收器的情况下组合mixins。从本质上讲，它涉及一个具有可变List[Receive]的基本特征，每个混合特征调用一个方法将其自己的接收添加到列表中。
trait ComposableActor extends Actor {
private var receives: List[Receive] = List()
protected def registerReceive(receive: Receive) {
receives = receive :: receives
}
def receive = receives reduce {_ orElse _}
}
trait IntActor extends ComposableActor {
registerReceive {
case i: Int => println("Int!")
}
}
trait StringActor extends ComposableActor {
registerReceive {
case s: String => println("String!")
}
}
val a = actorOf(new ComposableActor with IntActor with StringActor).start
a ! 5 //prints Int!
a ! "test" //prints String!唯一要记住的是，接收的顺序不应该是重要的，因为你不能很容易地预测哪个是链中的第一个，尽管你可以使用一个可变的hashmap而不是一个列表来解决这个问题。
Stack Overflow用户
发布于 2012-01-02 02:11:22
您可以在基本执行元类中使用空接收，在其定义中使用链接收。Akka 2.0-M2示例：
import akka.actor.Actor
import akka.actor.Props
import akka.event.Logging
import akka.actor.ActorSystem
class Logger extends Actor {
val log = Logging(context.system, this)
override def receive = new Receive {
def apply(any: Any) = {}
def isDefinedAt(any: Any) = false
}
}
trait Errors extends Logger {
override def receive = super.receive orElse {
case "error" => log.info("received error")
}
}
trait Warns extends Logger {
override def receive = super.receive orElse {
case "warn" => log.info("received warn")
}
}
object Main extends App {
val system = ActorSystem("mysystem")
val actor = system.actorOf(Props(new Logger with Errors with Warns), name = "logger")
actor ! "error"
actor ! "warn"
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/8681444
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