1 /*
2 * Copyright (c) 2000, 2007, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.awt;
27
28 import java.awt.IllegalComponentStateException;
29 import java.util.Collections;
30 import java.util.Iterator;
31 import java.util.HashMap;
32 import java.util.HashSet;
33 import java.util.Map;
34 import java.util.Set;
35 import java.util.WeakHashMap;
36
37 import sun.util.logging.PlatformLogger;
38
39 /**
40 * This class is used to aid in keeping track of DisplayChangedListeners and
41 * notifying them when a display change has taken place. DisplayChangedListeners
42 * are notified when the display's bit depth is changed, or when a top-level
43 * window has been dragged onto another screen.
44 *
45 * It is safe for a DisplayChangedListener to be added while the list is being
46 * iterated.
47 *
48 * The displayChanged() call is propagated after some occurrence (either
49 * due to user action or some other application) causes the display mode
50 * (e.g., depth or resolution) to change. All heavyweight components need
51 * to know when this happens because they need to create new surfaceData
52 * objects based on the new depth.
53 *
54 * displayChanged() is also called on Windows when they are moved from one
55 * screen to another on a system equipped with multiple displays.
56 */
57 public class SunDisplayChanger {
58
59 private static final PlatformLogger log = PlatformLogger.getLogger("sun.awt.multiscreen.SunDisplayChanger");
60
61 // Create a new synchronized map with initial capacity of one listener.
62 // It is asserted that the most common case is to have one GraphicsDevice
63 // and one top-level Window.
64 private Map<DisplayChangedListener, Void> listeners =
65 Collections.synchronizedMap(new WeakHashMap<DisplayChangedListener, Void>(1));
66
67 public SunDisplayChanger() {}
68
69 /*
70 * Add a DisplayChangeListener to this SunDisplayChanger so that it is
71 * notified when the display is changed.
72 */
73 public void add(DisplayChangedListener theListener) {
74 if (log.isLoggable(PlatformLogger.Level.FINE)) {
75 if (theListener == null) {
76 log.fine("Assertion (theListener != null) failed");
77 }
78 }
79 if (log.isLoggable(PlatformLogger.Level.FINER)) {
80 log.finer("Adding listener: " + theListener);
81 }
82 listeners.put(theListener, null);
83 }
84
85 /*
86 * Remove the given DisplayChangeListener from this SunDisplayChanger.
87 */
88 public void remove(DisplayChangedListener theListener) {
89 if (log.isLoggable(PlatformLogger.Level.FINE)) {
90 if (theListener == null) {
91 log.fine("Assertion (theListener != null) failed");
92 }
93 }
94 if (log.isLoggable(PlatformLogger.Level.FINER)) {
95 log.finer("Removing listener: " + theListener);
96 }
97 listeners.remove(theListener);
98 }
99
100 /*
101 * Notify our list of DisplayChangedListeners that a display change has
102 * taken place by calling their displayChanged() methods.
103 */
104 public void notifyListeners() {
105 if (log.isLoggable(PlatformLogger.Level.FINEST)) {
106 log.finest("notifyListeners");
107 }
108 // This method is implemented by making a clone of the set of listeners,
109 // and then iterating over the clone. This is because during the course
110 // of responding to a display change, it may be appropriate for a
111 // DisplayChangedListener to add or remove itself from a SunDisplayChanger.
112 // If the set itself were iterated over, rather than a clone, it is
113 // trivial to get a ConcurrentModificationException by having a
114 // DisplayChangedListener remove itself from its list.
115 // Because all display change handling is done on the event thread,
116 // synchronization provides no protection against modifying the listener
117 // list while in the middle of iterating over it. -bchristi 7/10/2001
118
119 Set<DisplayChangedListener> cloneSet;
120
121 synchronized(listeners) {
122 cloneSet = new HashSet<DisplayChangedListener>(listeners.keySet());
123 }
124
125 Iterator<DisplayChangedListener> itr = cloneSet.iterator();
126 while (itr.hasNext()) {
127 DisplayChangedListener current = itr.next();
128 try {
129 if (log.isLoggable(PlatformLogger.Level.FINEST)) {
130 log.finest("displayChanged for listener: " + current);
131 }
132 current.displayChanged();
133 } catch (IllegalComponentStateException e) {
134 // This DisplayChangeListener is no longer valid. Most
135 // likely, a top-level window was dispose()d, but its
136 // Java objects have not yet been garbage collected. In any
137 // case, we no longer need to track this listener, though we
138 // do need to remove it from the original list, not the clone.
139 listeners.remove(current);
140 }
141 }
142 }
143
144 /*
145 * Notify our list of DisplayChangedListeners that a palette change has
146 * taken place by calling their paletteChanged() methods.
147 */
148 public void notifyPaletteChanged() {
149 if (log.isLoggable(PlatformLogger.Level.FINEST)) {
150 log.finest("notifyPaletteChanged");
151 }
152 // This method is implemented by making a clone of the set of listeners,
153 // and then iterating over the clone. This is because during the course
154 // of responding to a display change, it may be appropriate for a
155 // DisplayChangedListener to add or remove itself from a SunDisplayChanger.
156 // If the set itself were iterated over, rather than a clone, it is
157 // trivial to get a ConcurrentModificationException by having a
158 // DisplayChangedListener remove itself from its list.
159 // Because all display change handling is done on the event thread,
160 // synchronization provides no protection against modifying the listener
161 // list while in the middle of iterating over it. -bchristi 7/10/2001
162
163 Set<DisplayChangedListener> cloneSet;
164
165 synchronized (listeners) {
166 cloneSet = new HashSet<DisplayChangedListener>(listeners.keySet());
167 }
168 Iterator<DisplayChangedListener> itr = cloneSet.iterator();
169 while (itr.hasNext()) {
170 DisplayChangedListener current = itr.next();
171 try {
172 if (log.isLoggable(PlatformLogger.Level.FINEST)) {
173 log.finest("paletteChanged for listener: " + current);
174 }
175 current.paletteChanged();
176 } catch (IllegalComponentStateException e) {
177 // This DisplayChangeListener is no longer valid. Most
178 // likely, a top-level window was dispose()d, but its
179 // Java objects have not yet been garbage collected. In any
180 // case, we no longer need to track this listener, though we
181 // do need to remove it from the original list, not the clone.
182 listeners.remove(current);
183 }
184 }
185 }
186 }