在Scala演员中访问共享资源的正确方法

我想知道“Scala演员”的做法如何运作.

假设我有一个java.sql.Connection对象的连接池,我希望提供线程安全的访问.我实现它作为一个接收消息并向发送方发送连接的演员.

看来有三种方法可以做到这一点：

>使用未来
>使用！
>需要连接的类也是一个演员

码：

sealed abstract class ConnectionPoolMessage
case class NewConnection extends ConnectionPoolMessage
case class CloseConnection(c:Connection) extends ConnectionPoolMessage

class ConnectionPool extends Actor {
  def act() {
    while (true) {
      receive() {
        case NewConnection => sender ! getConnectionFromPool
        case CloseConnection(conn) => returnConnection(conn)
      }
    }
  }
}

// Here,my "do stuff" method is all in one place,and I block waiting
// on the Future from the pool; however this could take forever and cause trouble
class UsingFuture {
  val pool = new ConnectionPool
  def doSomething() {
    val connectionFuture = pool !! NewConnection
    val connection = connectionFuture() // concerned that we can't timeout here
    // do stuff with my Connection instance
    pool ! CloseConnection(connection)  
  }
}


// here,I wait and just use a timeout
// Seems clean to me,I guess.
class UsingBangQuestion {
  val pool = new ConnectionPool
  def doSomething() {
    pool !?(TIMEOUT,NewConnection) match {
      case Some(conn) => {
        // do something with connection
        pool ! CloseConnection(conn)
      }
      case None => throw new RuntimeException("timed out")
    }
  }
}

// here,I don't worry about timeouts,cause I only use the
// the connection when I receive a message back with it.  
// The problem is that I now have to split my logic up
// with two methods
class AsAnActor extends Actor {
  val pool = new ConnectionPool
  def startSomething() {
    start
    pool ! NewConnection
  }
  def act() {
    receive() {
      case conn:Connection => finishSomething(conn)
    }
  }
  def finishSomething(conn:Connection) {
    // do stuff with my Connection
    pool ! CloseConnection(conn)
  }
}

未来版本似乎是最干净的,除了我可以阻止永远的事实.

有什么想法,还是我的这个错误的概念？