jdk/src/share/classes/sun/awt/SunDisplayChanger.java
changeset 2 90ce3da70b43
child 3938 ef327bd847c0
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/awt/SunDisplayChanger.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,189 @@
+/*
+ * Copyright 2000-2007 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+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);
+            }
+        }
+    }
+}