ScalaExampleChapter3の例を修正

/*
Scala Exsample Chapter 3
http://www29.atwiki.jp/tmiya/pages/26.html
Scala2.8で、オークション終了後、シャットダウンするまでの間にOfferメッセージを
受け取ったときの問題を修正したもの。
*/
class Auction(seller: Actor, minBid: Int, closing: Date) extends Actor { 
  val timeToShutdown = 36000000 // msec 
  val bidIncrement = 10 
  def act() { 
    var maxBid = minBid - bidIncrement 
    var maxBidder: Actor = null 
    loop { 
      receiveWithin ((closing.getTime() - new Date().getTime())) { 
        case Offer(bid, client) => 
          if (bid >= maxBid + bidIncrement) { 
            if (maxBid >= minBid) maxBidder ! BeatenOffer(bid) 
            maxBid = bid; maxBidder = client; client ! BestOffer 
          } else { 
            client ! BeatenOffer(maxBid) 
          } 
        case Inquire(client) => 
          client ! Status(maxBid, closing) 
        case TIMEOUT => 
          if (maxBid >= minBid) { 
            val reply = AuctionConcluded(seller, maxBidder) 
            maxBidder ! reply; seller ! reply 
          } else { 
            seller ! AuctionFailed 
          } 
          loop {
            receiveWithin(timeToShutdown) { 
              case Offer(_, client) => client ! AuctionOver 
              case TIMEOUT => actors.Actor.exit
            }
          } 
        } 
      } 
    } 
  }