Scala学习笔记--Actor和并发

//actor是一个类似线程的实体，它有一个用来接收消息的信箱。
//实现actor的方法是继承Scala.actors.Actor并完成其act方法
//通过调用actor的start方法来启动它
class SillyActor extends Actor{
  def act(){
    for(i<- 1 to 5){
      println("Actor"+i)
      Thread.sleep(1000);
    }
  }
}


object MyActor extends Actor{
  def act (){
    Actor.receive{
      case x:Int =>println("got an Int: "+x)
      case _ =>println("not an int")
    }
  }
}

object SimpleActor{
  def main(args:Array[String]):Unit = {
   /* 
    val sactor1 = new SillyActor();
    sactor1.start();
    
    //另一种方法：使用Actor中名为actor工具的方法来创建actor
    //actor在定义后立即启动，无需在调用start()
    val sactor2 = Actor.actor{
      for(i<-1 to 5){
        println("Another Actor"+i)
        Thread.sleep(1000);
      }
    }   */
    
    //另一种Actor，通过调用Actor.receive来接收消息
    //	actor发送消息时，它并不会阻塞，当actor接收消息时，它也不会被打断。发送的消息在接收actor的邮箱中等待处理，知道actor调用receive方法
    val sactor3 = Actor.actor{
      Actor.receive{
        case x :Int =>println("got an Int: "+x)
        case _ =>println("not an Int");
      }
    }    
    sactor3 ! 12
    //通过调用Actor.receive接收消息的另一种形式
    MyActor.start()
    MyActor ! 14
    
    //将原生线程当成Actor
    Actor.self ! 15;  //这句要放在前面，放在后面则程序不会停止
    Actor.self.receive{
      case x :Int =>println("got an Int: "+x)
      case _ =>println("not an Int");
    }
    //Actor.self ! 15
    /*
     * 解释
     * 如果使用原生线程，最好用receive的变种receiveWithin。
     * 此方法可以指定一个以毫秒计的超时时限。
     * 如果在解释器命令行中使用receive的话，receive将会阻塞命令行，直到有消息到来，
     * 对self.receive而言，可能意味着永远等待下去。
     * 应该使用receiveWithin。并给出超时值
     * self.receiveWithIn(1000){case x => x}
     * */
    
  }
}

object ReactActor{
  def main(args:Array[String]):Unit={
    NameResolver.start();
    NameResolver ! ("www.baidu.com",Actor.self)
    
    NameResolver ! "msg1";
    NameResolver ! "EXIT"
    NameResolver ! "msg2";//已经结束，不会显示
  }
}

object NameResolver extends Actor{
  def act(){
    react{
      case (name:String, actor:Actor)=>
        println(getIp(name))
        //actor ! getIp(name);
        act();
      case "EXIT" =>
        println("Name resorver exit!");
      case msg =>
        println("Unhandled message" + msg);
        act();
    }
  }
  
  //获取IP地址
  def getIp(name:String):Option[InetAddress]={
    try{
      Some(InetAddress.getByName(name))
    }catch{
      case _:UnknownHostException =>None
    }
  }
}