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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003, 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>ObservableUpdate</code>.
*
* @author Matthias Zenger
* @version 1.0, 08/07/2003
*/
abstract class ObservableMap[A, B, This <: ObservableMap[A, B, This]]: This
extends scala.collection.mutable.Map[A, B]
with Publisher[ObservableUpdate[Pair[A, B]] with Undo, This] {
abstract override def update(key: A, value: B): Unit = get(key) match {
case None => super.update(key, value);
publish(new Inclusion(Pair(key, value)) with Undo {
def undo = -=(key);
});
case Some(old) => super.update(key, value);
publish(new Modification(Pair(key, old), Pair(key, value)) with Undo {
def undo = update(key, old._2);
});
}
abstract override def -=(key: A): Unit = get(key) match {
case None =>
case Some(old) => super.-=(key);
publish(new Removal(Pair(key, old)) with Undo {
def undo = update(key, old);
});
}
abstract override def clear: Unit = {
super.clear;
publish(new Reset() with Undo { def undo: Unit = error("cannot undo"); });
}
}
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