Scala example source code file (ReactChannel.scala)

This example Scala source code file (ReactChannel.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

c, c, long, msg, msg, nothing, partialfunction, partialfunction, r, r, reactchannel, sendtoreactor, timeout, unit

The Scala ReactChannel.scala source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2005-2011, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */


package scala.actors

/**
 * @author Philipp Haller
 */
private[actors] class ReactChannel[Msg](receiver: ReplyReactor) extends InputChannel[Msg] {

  private case class SendToReactor(channel: ReactChannel[Msg], msg: Msg)

  /**
   * Sends a message to this <code>ReactChannel.
   *
   * @param  msg the message to be sent
   */
  def !(msg: Msg) {
    receiver ! SendToReactor(this, msg)
  }

  /**
   * Sends a message to this <code>ReactChannel
   * (asynchronous) supplying explicit reply destination.
   *
   * @param  msg     the message to send
   * @param  replyTo the reply destination
   */
  def send(msg: Msg, replyTo: OutputChannel[Any]) {
    receiver.send(SendToReactor(this, msg), replyTo)
  }

  /**
   * Forwards <code>msg to this keeping the
   * last sender as sender instead of <code>self.
   */
  def forward(msg: Msg) {
    receiver forward SendToReactor(this, msg)
  }

  /**
   * Receives a message from this <code>ReactChannel.
   * <p>
   * This method never returns. Therefore, the rest of the computation
   * has to be contained in the actions of the partial function.
   *
   * @param  f    a partial function with message patterns and actions
   */
  def react(f: PartialFunction[Msg, Unit]): Nothing = {
    val C = this
    receiver.react {
      case SendToReactor(C, msg) if (f.isDefinedAt(msg.asInstanceOf[Msg])) =>
        f(msg.asInstanceOf[Msg])
    }
  }

  /**
   * Receives a message from this <code>ReactChannel within
   * a certain time span.
   * <p>
   * This method never returns. Therefore, the rest of the computation
   * has to be contained in the actions of the partial function.
   *
   * @param  msec the time span before timeout
   * @param  f    a partial function with message patterns and actions
   */
  def reactWithin(msec: Long)(f: PartialFunction[Any, Unit]): Nothing = {
    val C = this
    val recvActor = receiver.asInstanceOf[Actor]
    recvActor.reactWithin(msec) {
      case C ! msg if (f.isDefinedAt(msg.asInstanceOf[Msg])) =>
        f(msg.asInstanceOf[Msg])
      case TIMEOUT => f(TIMEOUT)
    }
  }

  /**
   * Receives a message from this <code>ReactChannel.
   *
   * @param  f    a partial function with message patterns and actions
   * @return      result of processing the received value
   */
  def receive[R](f: PartialFunction[Msg, R]): R = {
    val C = this
    val recvActor = receiver.asInstanceOf[Actor]
    recvActor.receive {
      case C ! msg if (f.isDefinedAt(msg.asInstanceOf[Msg])) =>
        f(msg.asInstanceOf[Msg])
    }
  }

  /**
   * Receives a message from this <code>ReactChannel within a certain
   * time span.
   *
   * @param  msec the time span before timeout
   * @param  f    a partial function with message patterns and actions
   * @return      result of processing the received value
   */
  def receiveWithin[R](msec: Long)(f: PartialFunction[Any, R]): R = {
    val C = this
    val recvActor = receiver.asInstanceOf[Actor]
    recvActor.receiveWithin(msec) {
      case C ! msg if (f.isDefinedAt(msg.asInstanceOf[Msg])) =>
        f(msg.asInstanceOf[Msg])
      case TIMEOUT => f(TIMEOUT)
    }
  }

  /**
   * Receives the next message from this <code>ReactChannel.
   */
  def ? : Msg = receive {
    case x => x
  }

}