Source for java.awt.MenuBar

   1: /* MenuBar.java -- An AWT menu bar class
   2:    Copyright (C) 1999, 2000, 2001, 2002, 2004, 2005  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.awt;
  40: 
  41: import java.awt.peer.MenuBarPeer;
  42: import java.awt.peer.MenuComponentPeer;
  43: 
  44: import java.io.Serializable;
  45: import java.util.Enumeration;
  46: import java.util.Vector;
  47: 
  48: import javax.accessibility.Accessible;
  49: import javax.accessibility.AccessibleContext;
  50: import javax.accessibility.AccessibleRole;
  51: 
  52: /**
  53:   * This class implements a menu bar in the AWT system.
  54:   *
  55:   * @author Aaron M. Renn (arenn@urbanophile.com)
  56:   * @author Tom Tromey (tromey@redhat.com)
  57:   * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  58:   */
  59: public class MenuBar extends MenuComponent
  60:   implements MenuContainer, Serializable, Accessible
  61: {
  62: 
  63: /*
  64:  * Static Variables
  65:  */
  66: 
  67: // Serialization Constant
  68: private static final long serialVersionUID = -4930327919388951260L;
  69: 
  70: /*************************************************************************/
  71: 
  72: /*
  73:  * Instance Variables
  74:  */
  75: 
  76: /**
  77:   * @serial The menu used for providing help information
  78:   */
  79: private Menu helpMenu;
  80: 
  81: /**
  82:   * @serial The menus contained in this menu bar.
  83:   */
  84: private Vector menus = new Vector();
  85: 
  86:   /**
  87:    * The accessible context for this component.
  88:    *
  89:    * @see #getAccessibleContext()
  90:    * @serial ignored.
  91:    */
  92:   private transient AccessibleContext accessibleContext;
  93: 
  94: /*************************************************************************/
  95: 
  96: /*
  97:  * Constructors
  98:  */
  99: 
 100: /**
 101:   * Initializes a new instance of <code>MenuBar</code>.
 102:   *
 103:   * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true.
 104:   */
 105: public
 106: MenuBar()
 107: {
 108:   if (GraphicsEnvironment.isHeadless())
 109:     throw new HeadlessException ();
 110: }
 111: 
 112: /*************************************************************************/
 113: 
 114: /*
 115:  * Instance Methods
 116:  */
 117: 
 118: /**
 119:   * Returns the help menu for this menu bar.  This may be <code>null</code>.
 120:   *
 121:   * @return The help menu for this menu bar.
 122:   */
 123: public Menu
 124: getHelpMenu()
 125: {
 126:   return(helpMenu);
 127: }
 128: 
 129: /*************************************************************************/
 130: 
 131: /**
 132:   * Sets the help menu for this menu bar.
 133:   *
 134:   * @param menu The new help menu for this menu bar.
 135:   */
 136: public synchronized void
 137: setHelpMenu(Menu menu)
 138: {
 139:   if (helpMenu != null)
 140:     {
 141:       helpMenu.removeNotify ();
 142:       helpMenu.parent = null;
 143:     }
 144:   helpMenu = menu;
 145: 
 146:   if (menu.parent != null)
 147:     menu.parent.remove (menu);
 148:   menu.parent = this;
 149: 
 150:   MenuBarPeer peer = (MenuBarPeer) getPeer ();
 151:   if (peer != null)
 152:     {
 153:       menu.addNotify();
 154:       peer.addHelpMenu (menu);
 155:     }
 156: }
 157: 
 158: /*************************************************************************/
 159: 
 160: /** Add a menu to this MenuBar.  If the menu has already has a
 161:  * parent, it is first removed from its old parent before being
 162:  * added.
 163:  *
 164:  * @param menu The menu to add.
 165:  *
 166:  * @return The menu that was added.
 167:  */
 168: public synchronized Menu
 169: add(Menu menu)
 170: {
 171:   if (menu.parent != null)
 172:     menu.parent.remove (menu);
 173: 
 174:   menu.parent = this;
 175:   menus.addElement(menu);
 176: 
 177:   if (peer != null)
 178:     {
 179:       menu.addNotify();
 180:     }
 181: 
 182:   return(menu);
 183: }
 184: 
 185: /*************************************************************************/
 186: 
 187: /**
 188:   * Removes the menu at the specified index.
 189:   *
 190:   * @param index The index of the menu to remove from the menu bar.
 191:   */
 192: public synchronized void
 193: remove(int index)
 194: {
 195:   Menu m = (Menu) menus.get (index);
 196:   menus.remove (index);
 197:   m.removeNotify ();
 198:   m.parent = null;
 199: 
 200:   if (peer != null)
 201:     {
 202:       MenuBarPeer mp = (MenuBarPeer) peer;
 203:       mp.delMenu (index);
 204:     }
 205: }
 206: 
 207: /*************************************************************************/
 208: 
 209: /**
 210:   * Removes the specified menu from the menu bar.
 211:   *
 212:   * @param menu The menu to remove from the menu bar.
 213:   */
 214: public void
 215: remove(MenuComponent menu)
 216: {
 217:   int index = menus.indexOf(menu);
 218:   if (index == -1)
 219:     return;
 220: 
 221:   remove(index);
 222: }
 223: 
 224: /*************************************************************************/
 225: 
 226: /**
 227:   * Returns the number of elements in this menu bar.
 228:   *
 229:   * @return The number of elements in the menu bar.
 230:   */
 231: public int
 232: getMenuCount()
 233: {
 234:   return countMenus ();
 235: }
 236: 
 237: /*************************************************************************/
 238: 
 239: /**
 240:   * Returns the number of elements in this menu bar.
 241:   *
 242:   * @return The number of elements in the menu bar.
 243:   *
 244:   * @deprecated This method is deprecated in favor of <code>getMenuCount()</code>.
 245:   */
 246: public int
 247: countMenus()
 248: {
 249:   return menus.size () + (getHelpMenu () == null ? 0 : 1);
 250: }
 251: 
 252: /*************************************************************************/
 253: 
 254: /**
 255:   * Returns the menu at the specified index.
 256:   *
 257:   * @param index the index of the menu
 258:   *
 259:   * @return The requested menu.
 260:   *
 261:   * @exception ArrayIndexOutOfBoundsException If the index is not valid.
 262:   */
 263: public Menu
 264: getMenu(int index)
 265: {
 266:   return((Menu)menus.elementAt(index));
 267: }
 268: 
 269: /*************************************************************************/
 270: 
 271: /**
 272:   * Creates this object's native peer.
 273:   */
 274: public void
 275: addNotify()
 276: {
 277:   if (getPeer() == null)
 278:     setPeer((MenuComponentPeer)getToolkit().createMenuBar(this));
 279:   Enumeration e = menus.elements();
 280:   while (e.hasMoreElements())
 281:   {
 282:     Menu mi = (Menu)e.nextElement();
 283:     mi.addNotify();
 284:   }
 285:   if (helpMenu != null)
 286:   {
 287:     helpMenu.addNotify();
 288:     ((MenuBarPeer) peer).addHelpMenu(helpMenu);
 289:   }
 290: }
 291: 
 292: /*************************************************************************/
 293: 
 294: /**
 295:   * Destroys this object's native peer.
 296:   */
 297: public void
 298: removeNotify()
 299: {
 300:   Enumeration e = menus.elements();
 301:   while (e.hasMoreElements())
 302:   {
 303:     Menu mi = (Menu) e.nextElement();
 304:     mi.removeNotify();
 305:   }
 306:   super.removeNotify();
 307: }
 308: 
 309: /*************************************************************************/
 310: 
 311: /**
 312:   * Returns a list of all shortcuts for the menus in this menu bar.
 313:   *
 314:   * @return A list of all shortcuts for the menus in this menu bar.
 315:   */
 316: public synchronized Enumeration
 317: shortcuts()
 318: {
 319:   Vector shortcuts = new Vector();
 320:   Enumeration e = menus.elements();
 321: 
 322:   while (e.hasMoreElements())
 323:     {
 324:       Menu menu = (Menu)e.nextElement();
 325:       if (menu.getShortcut() != null)
 326:         shortcuts.addElement(menu.getShortcut());
 327:     }
 328: 
 329:   return(shortcuts.elements());
 330: }
 331: 
 332: /*************************************************************************/
 333: 
 334: /**
 335:   * Returns the menu item for the specified shortcut, or <code>null</code>
 336:   * if no such item exists.
 337:   *
 338:   * @param shortcut The shortcut to return the menu item for.
 339:   *
 340:   * @return The menu item for the specified shortcut.
 341:   */
 342: public MenuItem
 343: getShortcutMenuItem(MenuShortcut shortcut)
 344: {
 345:   Enumeration e = menus.elements();
 346: 
 347:   while (e.hasMoreElements())
 348:     {
 349:       Menu menu = (Menu)e.nextElement();
 350:       MenuShortcut s = menu.getShortcut();
 351:       if ((s != null) && (s.equals(shortcut)))
 352:         return(menu);
 353:     }
 354: 
 355:   return(null);
 356: }
 357: 
 358: /*************************************************************************/
 359: 
 360: /**
 361:   * Deletes the specified menu shortcut.
 362:   *
 363:   * @param shortcut The shortcut to delete.
 364:   */
 365: public void
 366: deleteShortcut(MenuShortcut shortcut)
 367: {
 368:   MenuItem it;
 369:   // This is a slow implementation, but it probably doesn't matter.
 370:   while ((it = getShortcutMenuItem (shortcut)) != null)
 371:     it.deleteShortcut ();
 372: }
 373: 
 374: /**
 375:  * Gets the AccessibleContext associated with this <code>MenuBar</code>.
 376:  * The context is created, if necessary.
 377:  *
 378:  * @return the associated context
 379:  */
 380: public AccessibleContext getAccessibleContext()
 381: {
 382:   /* Create the context if this is the first request */
 383:   if (accessibleContext == null)
 384:     accessibleContext = new AccessibleAWTMenuBar();
 385:   return accessibleContext;
 386: }
 387: 
 388: /**
 389:  * This class provides accessibility support for AWT menu bars.
 390:  *
 391:  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
 392:  */
 393: protected class AccessibleAWTMenuBar
 394:   extends AccessibleAWTMenuComponent
 395: {
 396:   
 397:   /**
 398:    * Compatible with JDK 1.4.2 revision 5
 399:    */
 400:   private static final long serialVersionUID = -8577604491830083815L;
 401: 
 402:   /**
 403:    * This is the default constructor, which simply calls the default
 404:    * constructor of the superclass.
 405:    */
 406:   protected AccessibleAWTMenuBar()
 407:   {
 408:     super();
 409:   }
 410: 
 411:   /**
 412:    * Returns the accessible role relating to the menu bar.
 413:    *
 414:    * @return <code>AccessibleRole.MENU_BAR</code>.
 415:    */
 416:   public AccessibleRole getAccessibleRole()
 417:   {
 418:     return AccessibleRole.MENU_BAR;
 419:   }
 420: 
 421: } // class AccessibleAWTMenuBar
 422: 
 423: } // class MenuBar