scala.actors.Channel.scala Maven / Gradle / Ivy
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2005-2006, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id: Channel.scala 10241 2007-03-08 10:06:20Z phaller $
package scala.actors
/**
* This class is used to pattern match on values that were sent
* to some channel Chann by the current
* actor self.
*
*
* The following example demonstrates its usage:
*
* receive {
* case Chan1 ! msg1 => ...
* case Chan2 ! msg2 => ...
* }
*
*
* @version 0.9.4
* @author Philipp Haller
*/
case class ! [a](ch: InputChannel[a], msg: a)
/**
* This class provides a means for typed communication among
* actors. Only the actor creating an instance of a
* Channel may receive from it.
*
* @version 0.9.4
* @author Philipp Haller
*/
class Channel[Msg] extends InputChannel[Msg] with OutputChannel[Msg] {
private[actors] var receiver: Actor = synchronized {
// basically Actor.self, but can be null
Actor.tl.get.asInstanceOf[Actor]
}
private[actors] def this(recv: Actor) = {
this()
receiver = recv
}
/**
* Sends a message to this Channel.
*
* @param msg the message to be sent
*/
def !(msg: Msg): unit = {
receiver ! scala.actors.!(this, msg)
}
/**
* Forwards msg to this keeping the
* last sender as sender instead of self.
*/
def forward(msg: Msg): unit = {
receiver forward scala.actors.!(this, msg)
}
/**
* Receives a message from this Channel.
*
* @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.asInstanceOf[Channel[Any]]
receiver.receive {
case C ! msg if (f.isDefinedAt(msg.asInstanceOf[Msg])) => f(msg.asInstanceOf[Msg])
}
}
/**
* Receives a message from this Channel 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.asInstanceOf[Channel[Any]]
receiver.receiveWithin(msec) {
case C ! msg if (f.isDefinedAt(msg)) => f(msg)
case TIMEOUT => f(TIMEOUT)
}
}
/**
* Receives a message from this Channel.
*
* 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.asInstanceOf[Channel[Any]]
receiver.react {
case C ! msg if (f.isDefinedAt(msg.asInstanceOf[Msg])) => f(msg.asInstanceOf[Msg])
}
}
/**
* Receives a message from this Channel within a certain
* time span.
*
* 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.asInstanceOf[Channel[Any]]
receiver.reactWithin(msec) {
case C ! msg if (f.isDefinedAt(msg)) => f(msg)
case TIMEOUT => f(TIMEOUT)
}
}
/**
* Sends a message to this Channel and
* awaits reply.
*
* @param msg the message to be sent
* @return the reply
*/
def !?(msg: Msg): Any = {
val replyChannel = Actor.self.freshReply()
receiver ! scala.actors.!(this, msg)
replyChannel.receive {
case x => x
}
}
/**
* Sends a message to this Channel and
* awaits reply within a certain time span.
*
* @param msec the time span before timeout
* @param msg the message to be sent
* @return None in case of timeout, otherwise
* Some(x) where x is the reply
*/
def !?(msec: long, msg: Msg): Option[Any] = {
val replyChannel = Actor.self.freshReply()
receiver ! scala.actors.!(this, msg)
replyChannel.receiveWithin(msec) {
case TIMEOUT => None
case x => Some(x)
}
}
}