/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2006, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection.mutable
/** This class is typically used as a mixin. It adds a subscription
* mechanism to the <code>Map</code> class into which this abstract
* class is mixed in. Class <code>ObservableMap</code> publishes
* events of the type <code>Message</code>.
*
* @author Matthias Zenger
* @author Martin Odersky
* @version 2.0, 31/12/2006
*/
trait ObservableMap[A, B, This <: ObservableMap[A, B, This]] requires This
extends Map[A, B]
with Publisher[Message[Pair[A, B]]
with Undoable, This]
{
abstract override def update(key: A, value: B): Unit = get(key) match {
case None =>
super.update(key, value)
publish(new Include(Pair(key, value)) with Undoable {
def undo = -=(key)
})
case Some(old) =>
super.update(key, value)
publish(new Update(Pair(key, value)) with Undoable {
def undo = update(key, old)
})
}
abstract override def -= (key: A): Unit = get(key) match {
case None =>
case Some(old) =>
super.-=(key)
publish(new Remove(Pair(key, old)) with Undoable {
def undo = update(key, old)
})
}
abstract override def clear: Unit = {
super.clear
publish(new Reset with Undoable {
def undo: Unit = throw new UnsupportedOperationException("cannot undo")
})
}
}