Scala de Design Pattern: Command

Commandパターン。
あまりScalaっぽくない。

trait Command {

    def execute: Unit

}
class CommandA extends Command {

    def execute = println("Execute CommandA")

}
class CommandB extends Command {

    def execute = println("Execute CommandB")

}
class Receiver {

    var commands = List[Command]()

    def addCommand(command: Command) = { commands :+= command }

    def execute = commands.foreach(_.execute)

}
object Main {

    def main(args: Array[String]) = {

        val receiver = new Receiver

        receiver.addCommand(new CommandA)

        receiver.addCommand(new CommandA)

        receiver.addCommand(new CommandB)

        receiver.execute

    }

}

　
Listへの末尾追加が『:+=』なのはちょっとキモイ。