继承消息处理行为

Question

我的模型中有一些事件和一些处理逻辑。我想组织通信逻辑抛出演员。但是我如何继承处理逻辑而不在每个具体类中指定 act()

简化示例

class Event {}

case class FooEvent(str : String) extends Event
case class BarEvent(i : java.lang.Integer) extends Event

trait FooListener extends Actor {
  def act() {
    react{
      case FooEvent => print("foo received")
    }
  }
}
trait BarListener extends Actor {
  def act() {
    react{
      case BarEvent => print("bar received")
    }
  }
}
class ListensOnlyBar extends BarListener{}

//can't be done: 
//error: overriding method act in trait FooListener of type ()Unit;
//method act in trait BarListener of type ()Unit needs `override' modifier
//class ListensBarAndFoo extends FooListener with BarListener{
class ListensBarAndFoo extends FooListener with BarListener{}

Answer 1

react 需要 PartialFunction[Any, Unit] 并且您可以很好地将它们组合在一起。这是一个例子：

type Listener = PartialFunction[Any, Unit]

val foo: Listener = {
  case FooEvent => print("foo received")
}

val bar: Listener = {
  case BarEvent => print("bar received")
}

case class GenericListener(listener: Listener) extends Actor {
  def act() {
    react(listener)
  }
}

GenericListener(bar)
GenericListener(foo orElse bar)