/*
* Copyright (c) 2000, 2007, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package sun.awt;
import java.awt.IllegalComponentStateException;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.HashMap;
import java.util.WeakHashMap;
import java.util.logging.*;
/**
* This class is used to aid in keeping track of DisplayChangedListeners and
* notifying them when a display change has taken place. DisplayChangedListeners
* are notified when the display's bit depth is changed, or when a top-level
* window has been dragged onto another screen.
*
* It is safe for a DisplayChangedListener to be added while the list is being
* iterated.
*
* The displayChanged() call is propagated after some occurrence (either
* due to user action or some other application) causes the display mode
* (e.g., depth or resolution) to change. All heavyweight components need
* to know when this happens because they need to create new surfaceData
* objects based on the new depth.
*
* displayChanged() is also called on Windows when they are moved from one
* screen to another on a system equipped with multiple displays.
*/
public class SunDisplayChanger {
private static final Logger log = Logger.getLogger("sun.awt.multiscreen.SunDisplayChanger");
// Create a new synchronizedMap with initial capacity of one listener.
// It is asserted that the most common case is to have one GraphicsDevice
// and one top-level Window.
private Map listeners = Collections.synchronizedMap(new WeakHashMap(1));
public SunDisplayChanger() {}
/*
* Add a DisplayChangeListener to this SunDisplayChanger so that it is
* notified when the display is changed.
*/
public void add(DisplayChangedListener theListener) {
if (log.isLoggable(Level.FINE)) {
if (theListener == null) {
log.log(Level.FINE, "Assertion (theListener != null) failed");
}
}
if (log.isLoggable(Level.FINER)) {
log.log(Level.FINER, "Adding listener: " + theListener);
}
listeners.put(theListener, null);
}
/*
* Remove the given DisplayChangeListener from this SunDisplayChanger.
*/
public void remove(DisplayChangedListener theListener) {
if (log.isLoggable(Level.FINE)) {
if (theListener == null) {
log.log(Level.FINE, "Assertion (theListener != null) failed");
}
}
if (log.isLoggable(Level.FINER)) {
log.log(Level.FINER, "Removing listener: " + theListener);
}
listeners.remove(theListener);
}
/*
* Notify our list of DisplayChangedListeners that a display change has
* taken place by calling their displayChanged() methods.
*/
public void notifyListeners() {
if (log.isLoggable(Level.FINEST)) {
log.log(Level.FINEST, "notifyListeners");
}
// This method is implemented by making a clone of the set of listeners,
// and then iterating over the clone. This is because during the course
// of responding to a display change, it may be appropriate for a
// DisplayChangedListener to add or remove itself from a SunDisplayChanger.
// If the set itself were iterated over, rather than a clone, it is
// trivial to get a ConcurrentModificationException by having a
// DisplayChangedListener remove itself from its list.
// Because all display change handling is done on the event thread,
// synchronization provides no protection against modifying the listener
// list while in the middle of iterating over it. -bchristi 7/10/2001
HashMap listClone;
Set cloneSet;
synchronized(listeners) {
listClone = new HashMap(listeners);
}
cloneSet = listClone.keySet();
Iterator itr = cloneSet.iterator();
while (itr.hasNext()) {
DisplayChangedListener current =
(DisplayChangedListener) itr.next();
try {
if (log.isLoggable(Level.FINEST)) {
log.log(Level.FINEST, "displayChanged for listener: " + current);
}
current.displayChanged();
} catch (IllegalComponentStateException e) {
// This DisplayChangeListener is no longer valid. Most
// likely, a top-level window was dispose()d, but its
// Java objects have not yet been garbage collected. In any
// case, we no longer need to track this listener, though we
// do need to remove it from the original list, not the clone.
listeners.remove(current);
}
}
}
/*
* Notify our list of DisplayChangedListeners that a palette change has
* taken place by calling their paletteChanged() methods.
*/
public void notifyPaletteChanged() {
if (log.isLoggable(Level.FINEST)) {
log.finest("notifyPaletteChanged");
}
// This method is implemented by making a clone of the set of listeners,
// and then iterating over the clone. This is because during the course
// of responding to a display change, it may be appropriate for a
// DisplayChangedListener to add or remove itself from a SunDisplayChanger.
// If the set itself were iterated over, rather than a clone, it is
// trivial to get a ConcurrentModificationException by having a
// DisplayChangedListener remove itself from its list.
// Because all display change handling is done on the event thread,
// synchronization provides no protection against modifying the listener
// list while in the middle of iterating over it. -bchristi 7/10/2001
HashMap listClone;
Set cloneSet;
synchronized (listeners) {
listClone = new HashMap(listeners);
}
cloneSet = listClone.keySet();
Iterator itr = cloneSet.iterator();
while (itr.hasNext()) {
DisplayChangedListener current =
(DisplayChangedListener) itr.next();
try {
if (log.isLoggable(Level.FINEST)) {
log.log(Level.FINEST, "paletteChanged for listener: " + current);
}
current.paletteChanged();
} catch (IllegalComponentStateException e) {
// This DisplayChangeListener is no longer valid. Most
// likely, a top-level window was dispose()d, but its
// Java objects have not yet been garbage collected. In any
// case, we no longer need to track this listener, though we
// do need to remove it from the original list, not the clone.
listeners.remove(current);
}
}
}
}