From aedc34d55462a75e329bbf342251ff6504cd117e Mon Sep 17 00:00:00 2001 From: Benjamin Culkin Date: Sun, 19 May 2024 17:56:33 -0400 Subject: Initial import from SVN --- .../net/wotonomy/control/EODelayedObserver.java | 152 +++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODelayedObserver.java (limited to 'projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODelayedObserver.java') diff --git a/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODelayedObserver.java b/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODelayedObserver.java new file mode 100644 index 0000000..758fb40 --- /dev/null +++ b/projects/net.wotonomy.persistence/src/main/java/net/wotonomy/control/EODelayedObserver.java @@ -0,0 +1,152 @@ +/* +Wotonomy: OpenStep design patterns for pure Java applications. +Copyright (C) 2000 Intersect Software Corporation + +This library is free software; you can redistribute it and/or +modify it under the terms of the GNU Lesser General Public +License as published by the Free Software Foundation; either +version 2.1 of the License, or (at your option) any later version. + +This library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Lesser General Public License for more details. + +You should have received a copy of the GNU Lesser General Public +License along with this library; if not, see http://www.gnu.org +*/ + +package net.wotonomy.control; + +import java.util.Observable; +import java.util.Observer; + +/** +* This is an abstract class for receiving coalesced +* notifications of changes from objects. +* This class also implements Observer for greater +* compatibility. +* The point of EODelayedObservers is that when +* they receive a willChange message, they +* queue themselves with a EODelayedObserverQueue +* so they can receive a single subjectChanged() +* after all changes from an observed object take +* place. +* +* @author michael@mpowers.net +* @author $Author: cgruber $ +* @version $Revision: 894 $ +*/ +public abstract class EODelayedObserver + implements EOObserving, Observer +{ + /** + * Notified immediately. + */ + public static final int ObserverPriorityImmediate = 0; + public static final int ObserverPriorityFirst = 1; + public static final int ObserverPrioritySecond = 2; + public static final int ObserverPriorityThird = 3; + public static final int ObserverPriorityFourth = 4; + public static final int ObserverPriorityFifth = 5; + public static final int ObserverPrioritySixth = 6; + public static final int ObserverPriorityLater = 7; + public static final int ObserverNumberOfPriorities = 8; + + /** + * Default constructor. + */ + public EODelayedObserver () + { + } + + /** + * Removes this observer from the observer queue + * for a currently pending notification. + */ + public void discardPendingNotification () + { + observerQueue().dequeueObserver( this ); + } + + /** + * Returns the observer queue to which this observer + * belongs. This implementation returns the default + * EODelayedObserverQueue. + * Override to use a different one. + */ + public EODelayedObserverQueue observerQueue () + { + return EODelayedObserverQueue.defaultObserverQueue(); + } + + /** + * Returns the priority of this observer in the queue. + * This implementation returns ObserverPriorityThird. + * Override to be notified before other observers. + */ + public int priority () + { + return ObserverPriorityThird; + } + + /** + * Notifies observer that one or more objects that + * it is observing have changed. The observer should + * check all objects it is observing for changes. + */ + public abstract void subjectChanged (); + + // interface EOObserving + + /** + * Called when the specified object is about to change. + * This implementation puts this observer on a + * notification queue. + */ + public void objectWillChange ( Object anObject ) + { + observerQueue().enqueueObserver( this ); + } + + // interface Observer + + /** + * Called when the specified object has changed, + * with the specified argument. + * This method is included for interacting with + * the java.lang.Observer pattern. + * This implementation simply objectWillChange(anObject) + * so that the observer still gets a single subjectChanged + * call in response to multiple changes. + */ + public void update ( Observable anObject, Object aValue ) + { + objectWillChange( anObject ); + } + +} + +/* + * $Log$ + * Revision 1.2 2006/02/16 16:47:14 cgruber + * Move some classes in to "internal" packages and re-work imports, etc. + * + * Also use UnsupportedOperationExceptions where appropriate, instead of WotonomyExceptions. + * + * Revision 1.1 2006/02/16 13:19:57 cgruber + * Check in all sources in eclipse-friendly maven-enabled packages. + * + * Revision 1.2 2001/10/26 18:38:10 mpowers + * Reordered priorities. + * + * Revision 1.1.1.1 2000/12/21 15:46:38 mpowers + * Contributing wotonomy. + * + * Revision 1.3 2000/12/20 16:25:35 michael + * Added log to all files. + * + * + */ + + -- cgit v1.2.3