001 /* MenuBar.java -- An AWT menu bar class
002 Copyright (C) 1999, 2000, 2001, 2002, 2004, 2005, 2006
003 Free Software Foundation, Inc.
004
005 This file is part of GNU Classpath.
006
007 GNU Classpath is free software; you can redistribute it and/or modify
008 it under the terms of the GNU General Public License as published by
009 the Free Software Foundation; either version 2, or (at your option)
010 any later version.
011
012 GNU Classpath is distributed in the hope that it will be useful, but
013 WITHOUT ANY WARRANTY; without even the implied warranty of
014 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 General Public License for more details.
016
017 You should have received a copy of the GNU General Public License
018 along with GNU Classpath; see the file COPYING. If not, write to the
019 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
020 02110-1301 USA.
021
022 Linking this library statically or dynamically with other modules is
023 making a combined work based on this library. Thus, the terms and
024 conditions of the GNU General Public License cover the whole
025 combination.
026
027 As a special exception, the copyright holders of this library give you
028 permission to link this library with independent modules to produce an
029 executable, regardless of the license terms of these independent
030 modules, and to copy and distribute the resulting executable under
031 terms of your choice, provided that you also meet, for each linked
032 independent module, the terms and conditions of the license of that
033 module. An independent module is a module which is not derived from
034 or based on this library. If you modify this library, you may extend
035 this exception to your version of the library, but you are not
036 obligated to do so. If you do not wish to do so, delete this
037 exception statement from your version. */
038
039
040 package java.awt;
041
042 import java.awt.peer.MenuBarPeer;
043
044 import java.io.Serializable;
045 import java.util.Enumeration;
046 import java.util.Vector;
047
048 import javax.accessibility.Accessible;
049 import javax.accessibility.AccessibleContext;
050 import javax.accessibility.AccessibleRole;
051
052 /**
053 * This class implements a menu bar in the AWT system.
054 *
055 * @author Aaron M. Renn (arenn@urbanophile.com)
056 * @author Tom Tromey (tromey@redhat.com)
057 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
058 */
059 public class MenuBar extends MenuComponent
060 implements MenuContainer, Serializable, Accessible
061 {
062
063 // Serialization Constant
064 private static final long serialVersionUID = -4930327919388951260L;
065
066 /**
067 * The number used to generate the name returned by getName.
068 */
069 private static transient long next_menubar_number;
070
071 /**
072 * @serial The menu used for providing help information
073 */
074 private Menu helpMenu;
075
076 /**
077 * @serial The menus contained in this menu bar.
078 */
079 private Vector menus = new Vector();
080
081 /**
082 * Initializes a new instance of <code>MenuBar</code>.
083 *
084 * @throws HeadlessException if GraphicsEnvironment.isHeadless() is true
085 */
086 public MenuBar()
087 {
088 if (GraphicsEnvironment.isHeadless())
089 throw new HeadlessException();
090 }
091
092 /**
093 * Returns the help menu for this menu bar. This may be <code>null</code>.
094 *
095 * @return the help menu for this menu bar
096 */
097 public Menu getHelpMenu()
098 {
099 return helpMenu;
100 }
101
102 /**
103 * Sets the help menu for this menu bar.
104 *
105 * @param menu the new help menu for this menu bar
106 */
107 public synchronized void setHelpMenu(Menu menu)
108 {
109 MenuBarPeer myPeer = (MenuBarPeer) getPeer ();
110
111 if (helpMenu != null)
112 {
113 if (myPeer != null)
114 helpMenu.removeNotify();
115 helpMenu.setParent(null);
116 }
117 helpMenu = menu;
118
119 MenuContainer parent = menu.getParent();
120 if (parent != null)
121 parent.remove(menu);
122 menu.setParent(this);
123
124 if (myPeer != null)
125 {
126 menu.addNotify();
127 myPeer.addHelpMenu(menu);
128 }
129 }
130
131 /**
132 * Add a menu to this MenuBar. If the menu has already has a
133 * parent, it is first removed from its old parent before being
134 * added.
135 *
136 * @param menu the menu to add
137 *
138 * @return the menu that was added
139 */
140 public synchronized Menu add(Menu menu)
141 {
142 MenuBarPeer myPeer = (MenuBarPeer) getPeer ();
143
144 MenuContainer parent = menu.getParent();
145 if (parent != null)
146 parent.remove(menu);
147
148 menus.addElement(menu);
149 menu.setParent(this);
150
151 if (myPeer != null)
152 {
153 menu.addNotify();
154 myPeer.addMenu(menu);
155 }
156 return menu;
157 }
158
159 /**
160 * Removes the menu at the specified index.
161 *
162 * @param index the index of the menu to remove from the menu bar
163 */
164 public synchronized void remove(int index)
165 {
166 Menu m = (Menu) menus.remove(index);
167 MenuBarPeer mp = (MenuBarPeer) getPeer();
168
169 if (mp != null)
170 m.removeNotify();
171
172 m.setParent(null);
173
174 if (mp != null)
175 mp.delMenu(index);
176 }
177
178 /**
179 * Removes the specified menu from the menu bar.
180 *
181 * @param menu the menu to remove from the menu bar
182 */
183 public void remove(MenuComponent menu)
184 {
185 int index = menus.indexOf(menu);
186 if (index == -1)
187 return;
188
189 remove(index);
190 }
191
192 /**
193 * Returns the number of elements in this menu bar.
194 *
195 * @return the number of elements in the menu bar
196 */
197 public int getMenuCount()
198 {
199 return countMenus();
200 }
201
202 /**
203 * Returns the number of elements in this menu bar.
204 *
205 * @return the number of elements in the menu bar
206 *
207 * @deprecated This method is deprecated in favor of
208 * <code>getMenuCount()</code>.
209 */
210 public int countMenus()
211 {
212 return menus.size() + (getHelpMenu() == null ? 0 : 1);
213 }
214
215 /**
216 * Returns the menu at the specified index.
217 *
218 * @param index the index of the menu
219 *
220 * @return the requested menu
221 *
222 * @throws ArrayIndexOutOfBoundsException if the index is not valid
223 */
224 public Menu getMenu(int index)
225 {
226 return (Menu) menus.elementAt(index);
227 }
228
229 /**
230 * Creates this object's native peer.
231 */
232 public void addNotify()
233 {
234 MenuBarPeer peer = (MenuBarPeer) getPeer();
235 if (peer == null)
236 {
237 peer = getToolkit().createMenuBar(this);
238 setPeer(peer);
239 }
240
241 Enumeration e = menus.elements();
242 while (e.hasMoreElements())
243 {
244 Menu mi = (Menu)e.nextElement();
245 mi.addNotify();
246 peer.addMenu(mi);
247 }
248
249 if (helpMenu != null)
250 {
251 helpMenu.addNotify();
252 peer.addHelpMenu(helpMenu);
253 }
254 }
255
256 /**
257 * Destroys this object's native peer.
258 */
259 public void removeNotify()
260 {
261 Enumeration e = menus.elements();
262 while (e.hasMoreElements())
263 {
264 Menu mi = (Menu) e.nextElement();
265 mi.removeNotify();
266 }
267 super.removeNotify();
268 }
269
270 /**
271 * Returns a list of all shortcuts for the menus in this menu bar.
272 *
273 * @return a list of all shortcuts for the menus in this menu bar
274 */
275 public synchronized Enumeration<MenuShortcut> shortcuts()
276 {
277 Vector shortcuts = new Vector();
278 Enumeration e = menus.elements();
279
280 while (e.hasMoreElements())
281 {
282 Menu menu = (Menu)e.nextElement();
283 if (menu.getShortcut() != null)
284 shortcuts.addElement(menu.getShortcut());
285 }
286
287 return shortcuts.elements();
288 }
289
290 /**
291 * Returns the menu item for the specified shortcut, or <code>null</code>
292 * if no such item exists.
293 *
294 * @param shortcut the shortcut to return the menu item for
295 *
296 * @return the menu item for the specified shortcut
297 */
298 public MenuItem getShortcutMenuItem(MenuShortcut shortcut)
299 {
300 Enumeration e = menus.elements();
301
302 while (e.hasMoreElements())
303 {
304 Menu menu = (Menu) e.nextElement();
305 MenuShortcut s = menu.getShortcut();
306 if ((s != null) && s.equals(shortcut))
307 return menu;
308 }
309
310 return null;
311 }
312
313 /**
314 * Deletes the specified menu shortcut.
315 *
316 * @param shortcut the shortcut to delete
317 */
318 public void deleteShortcut(MenuShortcut shortcut)
319 {
320 MenuItem it;
321 // This is a slow implementation, but it probably doesn't matter.
322 while ((it = getShortcutMenuItem (shortcut)) != null)
323 it.deleteShortcut();
324 }
325
326 /**
327 * Gets the AccessibleContext associated with this <code>MenuBar</code>.
328 * The context is created, if necessary.
329 *
330 * @return the associated context
331 */
332 public AccessibleContext getAccessibleContext()
333 {
334 // Create the context if this is the first request.
335 if (accessibleContext == null)
336 accessibleContext = new AccessibleAWTMenuBar();
337 return accessibleContext;
338 }
339
340 /**
341 * Generate a unique name for this <code>MenuBar</code>.
342 *
343 * @return A unique name for this <code>MenuBar</code>.
344 */
345 String generateName()
346 {
347 return "menubar" + getUniqueLong();
348 }
349
350 private static synchronized long getUniqueLong()
351 {
352 return next_menubar_number++;
353 }
354
355 /**
356 * This class provides accessibility support for AWT menu bars.
357 *
358 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
359 */
360 protected class AccessibleAWTMenuBar
361 extends AccessibleAWTMenuComponent
362 {
363
364 /**
365 * Compatible with JDK 1.4.2 revision 5
366 */
367 private static final long serialVersionUID = -8577604491830083815L;
368
369 /**
370 * This is the default constructor, which simply calls the default
371 * constructor of the superclass.
372 */
373 protected AccessibleAWTMenuBar()
374 {
375 super();
376 }
377
378 /**
379 * Returns the accessible role relating to the menu bar.
380 *
381 * @return <code>AccessibleRole.MENU_BAR</code>
382 */
383 public AccessibleRole getAccessibleRole()
384 {
385 return AccessibleRole.MENU_BAR;
386 }
387
388 }
389
390 }