scala - akka 类 Receive 定义在哪里？

Question

我对 Scala 还很陌生。

在一个 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 _ => 
  }
}

这个 Receive 类在哪里定义的？它没有导入到此类中。系统如何找到Receive类

Answer 1

它是分别在 akka.actor.Actor 伴随对象和特征中定义的 PartialFunction[Any, Unit] 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
    // ...
}