libjava/java/awt/MenuBar.java

   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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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