public SunDisplayChanger() 
{

}

 public  void add(DisplayChangedListener theListener) 
{
        if (log.isLoggable(PlatformLogger.FINE)) {
            if (theListener == null) {
                log.fine("Assertion (theListener != null) failed");
            }
        }
        if (log.isLoggable(PlatformLogger.FINER)) {
            log.finer("Adding listener: " + theListener);
        }
        listeners.put(theListener, null);
}

 public  void notifyListeners() 
{
        if (log.isLoggable(PlatformLogger.FINEST)) {
            log.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(PlatformLogger.FINEST)) {
                    log.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                // This DisplayChangeListener is no longer valid.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);
            }
        }
}

 public  void notifyPaletteChanged() 
{
        if (log.isLoggable(PlatformLogger.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(PlatformLogger.FINEST)) {
                    log.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);
            }
        }
}

 public  void remove(DisplayChangedListener theListener) 
{
        if (log.isLoggable(PlatformLogger.FINE)) {
            if (theListener == null) {
                log.fine("Assertion (theListener != null) failed");
            }
        }
        if (log.isLoggable(PlatformLogger.FINER)) {
            log.finer("Removing listener: " + theListener);
        }
        listeners.remove(theListener);
}