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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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*
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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.
/**
* 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);
}
}
}
}