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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2005-2007, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.actors
/** <p>
* This class is used to pattern match on values that were sent
* to some channel <code>Chan<sub>n</sub></code> by the current
* actor <code>self</code>.
* </p>
* <p>
* The following example demonstrates its usage:
* </p><pre>
* receive {
* <b>case</b> Chan1 ! msg1 => ...
* <b>case</b> Chan2 ! msg2 => ...
* }
* </pre>
*
* @version 0.9.8
* @author Philipp Haller
*/
case class ! [a](ch: Channel[a], msg: a)
/**
* This class provides a means for typed communication among
* actors. Only the actor creating an instance of a
* <code>Channel</code> may receive from it.
*
* @version 0.9.17
* @author Philipp Haller
*/
class Channel[Msg] extends InputChannel[Msg] with OutputChannel[Msg] {
private[actors] var recv: Actor = {
// basically Actor.self, but can be null
Actor.tl.get.asInstanceOf[Actor]
}
def receiver: Actor = recv
def this(recv: Actor) = {
this()
this.recv = recv
}
/**
* Sends a message to this <code>Channel</code>.
*
* @param msg the message to be sent
*/
def !(msg: Msg) {
recv ! scala.actors.!(this, msg)
}
/**
* Sends a message to this <code>Channel</code>
* (asynchronous) supplying explicit reply destination.
*
* @param msg the message to send
* @param replyTo the reply destination
*/
def send(msg: Msg, replyTo: OutputChannel[Any]) {
recv.send(scala.actors.!(this, msg), replyTo)
}
/**
* Forwards <code>msg</code> to <code>this</code> keeping the
* last sender as sender instead of <code>self</code>.
*/
def forward(msg: Msg) {
recv forward scala.actors.!(this, msg)
}
/**
* Receives a message from this <code>Channel</code>.
*
* @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]]
recv.receive {
case C ! msg if (f.isDefinedAt(msg.asInstanceOf[Msg])) => f(msg.asInstanceOf[Msg])
}
}
/**
* Receives the next message from this <code>Channel</code>.
*/
def ? : Msg = receive {
case x => x
}
/**
* Receives a message from this <code>Channel</code> 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]]
recv.receiveWithin(msec) {
case C ! msg if (f.isDefinedAt(msg)) => f(msg)
case TIMEOUT => f(TIMEOUT)
}
}
/**
* Receives a message from this <code>Channel</code>.
* <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.asInstanceOf[Channel[Any]]
recv.react {
case C ! msg if (f.isDefinedAt(msg.asInstanceOf[Msg])) => f(msg.asInstanceOf[Msg])
}
}
/**
* Receives a message from this <code>Channel</code> 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.asInstanceOf[Channel[Any]]
recv.reactWithin(msec) {
case C ! msg if (f.isDefinedAt(msg)) => f(msg)
case TIMEOUT => f(TIMEOUT)
}
}
/**
* Sends a message to this <code>Channel</code> and
* awaits reply.
*
* @param msg the message to be sent
* @return the reply
*/
def !?(msg: Msg): Any = {
val replyCh = Actor.self.freshReplyChannel
recv.send(scala.actors.!(this, msg), replyCh)
replyCh.receive {
case x => x
}
}
/**
* Sends a message to this <code>Channel</code> and
* awaits reply within a certain time span.
*
* @param msec the time span before timeout
* @param msg the message to be sent
* @return <code>None</code> in case of timeout, otherwise
* <code>Some(x)</code> where <code>x</code> is the reply
*/
def !?(msec: Long, msg: Msg): Option[Any] = {
val replyCh = Actor.self.freshReplyChannel
recv.send(scala.actors.!(this, msg), replyCh)
replyCh.receiveWithin(msec) {
case TIMEOUT => None
case x => Some(x)
}
}
}
|
