akka类接收定义在哪里？

Question

我是Scala的新手。

在其中一个Actor类中，我看到我的同事定义了这样的代码

导入akka.actor.Actor

class Processor extends Actor {

  def receive: Receive = {
    case msg: String => doProcess(msg)
    case _ => 
  }
}

此类接收定义在哪里？它不会导入此类。系统将如何找到Receive类

Answer 1

它是分别在PartialFunction[Any, Unit]伴侣对象和特征中定义的akka.actor.Actor的类型别名。

摘自source code：

object Actor {
    // Type alias representing a Receive-expression for Akka Actors.
    type Receive = PartialFunction[Any, Unit]
    // ...
}

trait Actor {
    // to make type Receive known in subclasses without import
    type Receive = Actor.Receive
    // ...
}

Answer 2

Receive是PartialFunction[Any,Unit]的类型别名。此类型别名在Actor伴随对象上定义，然后在Actor特征上重新定义（因此在Actor impl中可用），引用伴侣上定义的特征。

Answer 3

Receive是PartialFunction [Any，Unit]

的类型别名

查看Actor源代码here

您也可以将接收方法编写为

def receive: PartialFunction[Any, Unit] = {
    ….
 }