libjava/java/awt/Menu.java

   1 /* Menu.java -- A Java AWT Menu
   2    Copyright (C) 1999, 2002, 2004 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.MenuPeer;
  42 import java.io.Serializable;
  43 import java.util.Enumeration;
  44 import java.util.Vector;
  45
  46 import javax.accessibility.AccessibleContext;
  47 import javax.accessibility.AccessibleRole;
  48
  49 /**
  50   * This class represents a pull down or tear off menu in Java's AWT.
  51   *
  52   * @author Aaron M. Renn (arenn@urbanophile.com)
  53   */
  54 public class Menu extends MenuItem implements MenuContainer, Serializable
  55 {
  56
  57 /*
  58  * Static Variables
  59  */
  60
  61 // Serialization Constant
  62 private static final long serialVersionUID = -8809584163345499784L;
  63
  64 /*************************************************************************/
  65
  66 /*
  67  * Instance Variables
  68  */
  69
  70 /**
  71   * @serial The actual items in the menu
  72   */
  73 private Vector items = new Vector();
  74
  75 /**
  76   * @serial Flag indicating whether or not this menu is a tear off
  77   */
  78 private boolean tearOff;
  79
  80 /**
  81   * @serial Indicates whether or not this is a help menu.
  82   */
  83 private boolean isHelpMenu;
  84
  85   /*
  86    * @serial Unused in this implementation, but present in Sun's
  87    * serialization spec.  Value obtained via reflection.
  88    */
  89   private int menuSerializedDataVersion = 1;
  90
  91 static final transient String separatorLabel = "-";
  92
  93 /*************************************************************************/
  94
  95 /*
  96  * Constructors
  97  */
  98
  99 /**
 100   * Initializes a new instance of <code>Menu</code> with no label and that
 101   * is not a tearoff;
 102   *
 103   * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true.
 104   */
 105 public
 106 Menu()
 107 {
 108 }
 109
 110 /*************************************************************************/
 111
 112 /**
 113   * Initializes a new instance of <code>Menu</code> that is not a tearoff and
 114   * that has the specified label.
 115   *
 116   * @param label The menu label.
 117   *
 118   * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true.
 119   */
 120 public
 121 Menu(String label)
 122 {
 123   this(label, false);
 124 }
 125
 126 /*************************************************************************/
 127
 128 /**
 129   * Initializes a new instance of <code>Menu</code> with the specified
 130   * label and tearoff status.
 131   *
 132   * @param label The label for this menu
 133   * @param isTearOff <code>true</code> if this menu is a tear off menu,
 134   * <code>false</code> otherwise.
 135   *
 136   * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true.
 137   */
 138 public
 139 Menu(String label, boolean isTearOff)
 140 {
 141   super(label);
 142
 143   tearOff = isTearOff;
 144
 145   if (label.equals("Help"))
 146     isHelpMenu = true;
 147
 148   if (GraphicsEnvironment.isHeadless())
 149     throw new HeadlessException ();
 150 }
 151
 152 /*************************************************************************/
 153
 154 /*
 155  * Instance Methods
 156  */
 157
 158 /**
 159   * Tests whether or not this menu is a tearoff.
 160   *
 161   * @return <code>true</code> if this menu is a tearoff, <code>false</code>
 162   * otherwise.
 163   */
 164 public boolean
 165 isTearOff()
 166 {
 167   return(tearOff);
 168 }
 169
 170 /*************************************************************************/
 171
 172 /**
 173   * Returns the number of items in this menu.
 174   *
 175   * @return The number of items in this menu.
 176   */
 177 public int
 178 getItemCount()
 179 {
 180   return countItems ();
 181 }
 182
 183 /**
 184  * Returns the number of items in this menu.
 185  *
 186  * @return The number of items in this menu.
 187  *
 188  * @deprecated As of JDK 1.1, replaced by getItemCount().
 189  */
 190 public int countItems ()
 191 {
 192   return items.size ();
 193 }
 194
 195 /*************************************************************************/
 196
 197 /**
 198   * Returns the item at the specified index.
 199   *
 200   * @return The item at the specified index.
 201   *
 202   * @exception ArrayIndexOutOfBoundsException If the index value is not valid.
 203   */
 204 public MenuItem
 205 getItem(int index)
 206 {
 207   return((MenuItem)items.elementAt(index));
 208 }
 209
 210 /*************************************************************************/
 211
 212 /**
 213   * Adds the specified item to this menu.  If it was previously part of
 214   * another menu, it is first removed from that menu.
 215   *
 216   * @param item The new item to add.
 217   *
 218   * @return The item that was added.
 219   */
 220 public MenuItem
 221 add(MenuItem item)
 222 {
 223   items.addElement(item);
 224   if (item.parent != null)
 225     {
 226       item.parent.remove(item);
 227     }
 228   item.parent = this;
 229
 230   if (peer != null)
 231     {
 232       MenuPeer mp = (MenuPeer) peer;
 233       mp.addItem(item);
 234     }
 235
 236   return item;
 237 }
 238
 239 /*************************************************************************/
 240
 241 /**
 242   * Add an item with the specified label to this menu.
 243   *
 244   * @param label The label of the menu item to add.
 245   */
 246 public void
 247 add(String label)
 248 {
 249   add(new MenuItem(label));
 250 }
 251
 252 /*************************************************************************/
 253
 254 /**
 255   * Inserts the specified menu item into this menu at the specified index.
 256   *
 257   * @param item The menu item to add.
 258   * @param index The index of the menu item.
 259   *
 260   * @exception IllegalArgumentException If the index is less than zero.
 261   * @exception ArrayIndexOutOfBoundsException If the index is otherwise invalid.
 262   */
 263 public void
 264 insert(MenuItem item, int index)
 265 {
 266   if (index < 0)
 267     throw new IllegalArgumentException("Index is less than zero");
 268
 269   MenuPeer peer = (MenuPeer) getPeer();
 270   if (peer == null)
 271     return;
 272
 273   int count = getItemCount ();
 274
 275   if (index >= count)
 276     peer.addItem (item);
 277   else
 278     {
 279       for (int i = count - 1; i >= index; i--)
 280         peer.delItem (i);
 281
 282       peer.addItem (item);
 283
 284       for (int i = index; i < count; i++)
 285         peer.addItem ((MenuItem) items.elementAt (i));
 286     }
 287
 288   items.insertElementAt(item, index);
 289 }
 290
 291 /*************************************************************************/
 292
 293 /**
 294   * Inserts an item with the specified label into this menu at the specified index.
 295   *
 296   * @param label The label of the item to add.
 297   * @param index The index of the menu item.
 298   *
 299   * @exception IllegalArgumentException If the index is less than zero.
 300   * @exception ArrayIndexOutOfBoundsException If the index is otherwise invalid.
 301   */
 302 public void
 303 insert(String label, int index)
 304 {
 305   insert(new MenuItem(label), index);
 306 }
 307
 308 /*************************************************************************/
 309
 310 /**
 311   * Adds a separator bar at the current menu location.
 312   */
 313 public void
 314 addSeparator()
 315 {
 316   add(new MenuItem(separatorLabel));
 317 }
 318
 319 /*************************************************************************/
 320
 321 /**
 322   * Inserts a separator bar at the specified index value.
 323   *
 324   * @param index The index at which to insert a separator bar.
 325   *
 326   * @exception IllegalArgumentException If the index is less than zero.
 327   * @exception ArrayIndexOutOfBoundsException If the index is otherwise invalid.
 328   */
 329 public void
 330 insertSeparator(int index)
 331 {
 332   insert(new MenuItem(separatorLabel), index);
 333 }
 334
 335 /*************************************************************************/
 336
 337 /**
 338   * Deletes the item at the specified index from this menu.
 339   *
 340   * @param index The index of the item to remove.
 341   *
 342   * @exception ArrayIndexOutOfBoundsException If the index is otherwise invalid.
 343   */
 344 public synchronized void
 345 remove(int index)
 346 {
 347   items.removeElementAt(index);
 348
 349   MenuPeer mp = (MenuPeer)getPeer();
 350   if (mp != null)
 351     mp.delItem(index);
 352 }
 353
 354 /*************************************************************************/
 355
 356 /**
 357   * Removes the specifed item from the menu.  If the specified component
 358   * does not exist, this method does nothing.
 359   *
 360   * @param item The component to remove.
 361   */
 362 public void
 363 remove(MenuComponent item)
 364 {
 365   int index = items.indexOf(item);
 366   if (index == -1)
 367     return;
 368
 369   remove(index);
 370 }
 371
 372 /*************************************************************************/
 373
 374 /**
 375   * Removes all the elements from this menu.
 376   */
 377 public synchronized void
 378 removeAll()
 379 {
 380   int count = getItemCount();
 381   for(int i = 0; i < count; i++)
 382     {
 383       // We must always remove item 0.
 384       remove(0);
 385     }
 386 }
 387
 388 /*************************************************************************/
 389
 390 /**
 391   * Creates the native peer for this object.
 392   */
 393 public void
 394 addNotify()
 395 {
 396   if (peer == null)
 397     peer = getToolkit().createMenu(this);
 398   Enumeration e = items.elements();
 399   while (e.hasMoreElements())
 400   {
 401     MenuItem mi = (MenuItem)e.nextElement();
 402     mi.addNotify();
 403   }
 404   super.addNotify ();
 405 }
 406
 407 /*************************************************************************/
 408
 409 /**
 410   * Destroys the native peer for this object.
 411   */
 412 public void
 413 removeNotify()
 414 {
 415   Enumeration e = items.elements();
 416   while (e.hasMoreElements())
 417   {
 418     MenuItem mi = (MenuItem) e.nextElement();
 419     mi.removeNotify();
 420   }
 421   super.removeNotify();
 422 }
 423
 424 /*************************************************************************/
 425
 426 /**
 427   * Returns a debugging string for this menu.
 428   *
 429   * @return A debugging string for this menu.
 430   */
 431 public String
 432 paramString()
 433 {
 434   return (",tearOff=" + tearOff + ",isHelpMenu=" + isHelpMenu
 435           + super.paramString());
 436 }
 437
 438   /**
 439    * Basic Accessibility class for Menu.  Details get provided in derived
 440    * classes.
 441    */
 442   protected class AccessibleAWTMenu extends AccessibleAWTMenuItem
 443   {
 444     protected AccessibleAWTMenu()
 445     {
 446     }
 447
 448     public AccessibleRole getAccessibleRole()
 449     {
 450       return AccessibleRole.MENU;
 451     }
 452   }
 453
 454   /**
 455    * Gets the AccessibleContext associated with this <code>Menu</code>.
 456    * The context is created, if necessary.
 457    *
 458    * @return the associated context
 459    */
 460   public AccessibleContext getAccessibleContext()
 461   {
 462     /* Create the context if this is the first request */
 463     if (accessibleContext == null)
 464       accessibleContext = new AccessibleAWTMenu();
 465     return accessibleContext;
 466   }
 467
 468 } // class Menu