libjava/java/awt/MenuItem.java

   1 /* MenuItem.java -- An item in a menu
   2    Copyright (C) 1999, 2000, 2001, 2002, 2003 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.event.ActionEvent;
  42 import java.awt.event.ActionListener;
  43 import java.awt.peer.MenuItemPeer;
  44 import java.io.Serializable;
  45 import java.lang.reflect.Array;
  46 import java.util.EventListener;
  47
  48 /**
  49   * This class represents an item in a menu.
  50   *
  51   * @author Aaron M. Renn (arenn@urbanophile.com)
  52   */
  53 public class MenuItem extends MenuComponent
  54   implements Serializable
  55 {
  56
  57 // FIXME: The enabled event mask is not used at this time.
  58
  59 /*
  60  * Static Variables
  61  */
  62
  63 // Serialization Constant
  64 private static final long serialVersionUID = -21757335363267194L;
  65
  66 /*************************************************************************/
  67
  68 /*
  69  * Instance Variables
  70  */
  71
  72 /**
  73   * @serial The name of the action command generated by this item.
  74   */
  75 private String actionCommand;
  76
  77 /**
  78   * @serial Indicates whether or not this menu item is enabled.
  79   */
  80 private boolean enabled;
  81
  82 /**
  83   * @serial The mask of events that are enabled for this menu item.
  84   */
  85 long eventMask;
  86
  87 /**
  88   * @serial This menu item's label
  89   */
  90 private String label;
  91
  92 /**
  93   * @serial The shortcut for this menu item, if any
  94   */
  95 private MenuShortcut shortcut;
  96
  97 // The list of action listeners for this menu item.
  98 private transient ActionListener action_listeners;
  99
 100 /*************************************************************************/
 101
 102 /*
 103  * Constructors
 104  */
 105
 106 /**
 107   * Initializes a new instance of <code>MenuItem</code> with no label
 108   * and no shortcut.
 109   */
 110 public
 111 MenuItem()
 112 {
 113 }
 114
 115 /*************************************************************************/
 116
 117 /**
 118   * Initializes a new instance of <code>MenuItem</code> with the specified
 119   * label and no shortcut.
 120   *
 121   * @param label The label for this menu item.
 122   */
 123 public
 124 MenuItem(String label)
 125 {
 126   this.label = label;
 127 }
 128
 129 /*************************************************************************/
 130
 131 /**
 132   * Initializes a new instance of <code>MenuItem</code> with the specified
 133   * label and shortcut.
 134   *
 135   * @param label The label for this menu item.
 136   * @param shortcut The shortcut for this menu item.
 137   */
 138 public
 139 MenuItem(String label, MenuShortcut shortcut)
 140 {
 141   this.label = label;
 142   this.shortcut = shortcut;
 143 }
 144
 145 /*************************************************************************/
 146
 147 /*
 148  * Instance Methods
 149  */
 150
 151 /**
 152   * Returns the label for this menu item, which may be <code>null</code>.
 153   *
 154   * @return The label for this menu item.
 155   */
 156 public String
 157 getLabel()
 158 {
 159   return(label);
 160 }
 161
 162 /*************************************************************************/
 163
 164 /**
 165   * This method sets the label for this menu to the specified value.
 166   *
 167   * @param label The new label for this menu item.
 168   */
 169 public synchronized void
 170 setLabel(String label)
 171 {
 172   this.label = label;
 173   if (peer != null)
 174     {
 175       MenuItemPeer mp = (MenuItemPeer) peer;
 176       mp.setLabel (label);
 177     }
 178 }
 179
 180 /*************************************************************************/
 181
 182 /**
 183   * Tests whether or not this menu item is enabled.
 184   *
 185   * @return <code>true</code> if this menu item is enabled, <code>false</code>
 186   * otherwise.
 187   */
 188 public boolean
 189 isEnabled()
 190 {
 191   return(enabled);
 192 }
 193
 194 /*************************************************************************/
 195
 196 /**
 197   * Sets the enabled status of this menu item.
 198   *
 199   * @param enabled <code>true</code> to enable this menu item,
 200   * <code>false</code> otherwise.
 201   */
 202 public synchronized void
 203 setEnabled(boolean enabled)
 204 {
 205   if (enabled == this.enabled)
 206     return;
 207
 208   this.enabled = enabled;
 209   if (peer != null)
 210     {
 211       MenuItemPeer mp = (MenuItemPeer) peer;
 212       mp.setEnabled (enabled);
 213     }
 214 }
 215
 216 /*************************************************************************/
 217
 218 /**
 219   * Sets the enabled status of this menu item.
 220   *
 221   * @param enabled <code>true</code> to enable this menu item,
 222   * <code>false</code> otherwise.
 223   *
 224   * @deprecated This method is deprecated in favor of <code>setEnabled()</code>.
 225   */
 226 public void
 227 enable(boolean enabled)
 228 {
 229   setEnabled(enabled);
 230 }
 231
 232 /*************************************************************************/
 233
 234 /**
 235   * Enables this menu item.
 236   *
 237   * @deprecated This method is deprecated in favor of <code>setEnabled()</code>.
 238   */
 239 public void
 240 enable()
 241 {
 242   setEnabled(true);
 243 }
 244
 245 /*************************************************************************/
 246
 247 /**
 248   * Disables this menu item.
 249   *
 250   * @deprecated This method is deprecated in favor of <code>setEnabled()</code>.
 251   */
 252 public void
 253 disable()
 254 {
 255   setEnabled(false);
 256 }
 257
 258 /*************************************************************************/
 259
 260 /**
 261   * Returns the shortcut for this menu item, which may be <code>null</code>.
 262   *
 263   * @return The shortcut for this menu item.
 264   */
 265 public MenuShortcut
 266 getShortcut()
 267 {
 268   return(shortcut);
 269 }
 270
 271 /*************************************************************************/
 272
 273 /**
 274   * Sets the shortcut for this menu item to the specified value.  This
 275   * must be done before the native peer is created.
 276   *
 277   * @param shortcut The new shortcut for this menu item.
 278   */
 279 public void
 280 setShortcut(MenuShortcut shortcut)
 281 {
 282   this.shortcut = shortcut;
 283 }
 284
 285 /*************************************************************************/
 286
 287 /**
 288   * Deletes the shortcut for this menu item if one exists.  This must be
 289   * done before the native peer is created.
 290   */
 291 public void
 292 deleteShortcut()
 293 {
 294   shortcut = null;
 295 }
 296
 297 /*************************************************************************/
 298
 299 /**
 300   * Returns the name of the action command in the action events
 301   * generated by this menu item.
 302   *
 303   * @return The action command name
 304   */
 305 public String
 306 getActionCommand()
 307 {
 308   return(actionCommand);
 309 }
 310
 311 /*************************************************************************/
 312
 313 /**
 314   * Sets the name of the action command in the action events generated by
 315   * this menu item.
 316   *
 317   * @param actionCommand The new action command name.
 318   */
 319 public void
 320 setActionCommand(String actionCommand)
 321 {
 322   this.actionCommand = actionCommand;
 323 }
 324
 325 /*************************************************************************/
 326
 327 /**
 328   * Enables the specified events.  This is done automatically when a
 329   * listener is added and does not normally need to be done by
 330   * application code.
 331   *
 332   * @param events The events to enable, which should be the bit masks
 333   * from <code>AWTEvent</code>.
 334   */
 335 protected final void
 336 enableEvents(long events)
 337 {
 338   eventMask |= events;
 339   // TODO: see comment in Component.enableEvents().
 340 }
 341
 342 /*************************************************************************/
 343
 344 /**
 345   * Disables the specified events.
 346   *
 347   * @param events The events to enable, which should be the bit masks
 348   * from <code>AWTEvent</code>.
 349   */
 350 protected final void
 351 disableEvents(long events)
 352 {
 353   eventMask &= ~events;
 354 }
 355
 356 /*************************************************************************/
 357
 358 /**
 359   * Creates the native peer for this object.
 360   */
 361 public void
 362 addNotify()
 363 {
 364   if (peer != null)
 365     peer = getToolkit ().createMenuItem (this);
 366 }
 367
 368 /*************************************************************************/
 369
 370 /**
 371   * Adds the specified listener to the list of registered action listeners
 372   * for this component.
 373   *
 374   * @param listener The listener to add.
 375   */
 376 public synchronized void
 377 addActionListener(ActionListener listener)
 378 {
 379   action_listeners = AWTEventMulticaster.add(action_listeners, listener);
 380
 381   enableEvents(AWTEvent.ACTION_EVENT_MASK);
 382 }
 383
 384 public synchronized void
 385 removeActionListener(ActionListener l)
 386 {
 387   action_listeners = AWTEventMulticaster.remove(action_listeners, l);
 388 }
 389
 390   public synchronized ActionListener[] getActionListeners()
 391   {
 392     return (ActionListener[])
 393       AWTEventMulticaster.getListeners(action_listeners,
 394                                        ActionListener.class);
 395   }
 396
 397 /** Returns all registered EventListers of the given listenerType.
 398  * listenerType must be a subclass of EventListener, or a
 399  * ClassClassException is thrown.
 400  * @since 1.3
 401  */
 402   public EventListener[] getListeners(Class listenerType)
 403   {
 404     if (listenerType == ActionListener.class)
 405       return getActionListeners();
 406     return (EventListener[]) Array.newInstance(listenerType, 0);
 407   }
 408
 409 /*************************************************************************/
 410
 411 void
 412 dispatchEventImpl(AWTEvent e)
 413 {
 414   if (e.id <= ActionEvent.ACTION_LAST
 415       && e.id >= ActionEvent.ACTION_FIRST
 416       && (action_listeners != null
 417           || (eventMask & AWTEvent.ACTION_EVENT_MASK) != 0))
 418     processEvent(e);
 419 }
 420
 421 /**
 422   * Processes the specified event by calling <code>processActionEvent()</code>
 423   * if it is an instance of <code>ActionEvent</code>.
 424   *
 425   * @param event The event to process.
 426   */
 427 protected void
 428 processEvent(AWTEvent event)
 429 {
 430   if (event instanceof ActionEvent)
 431     processActionEvent((ActionEvent)event);
 432 }
 433
 434 /*************************************************************************/
 435
 436 /**
 437   * Processes the specified event by dispatching it to any registered listeners.
 438   *
 439   * @param event The event to process.
 440   */
 441 protected void
 442 processActionEvent(ActionEvent event)
 443 {
 444   if (action_listeners != null)
 445     action_listeners.actionPerformed(event);
 446 }
 447
 448 /*************************************************************************/
 449
 450 /**
 451   * Returns a debugging string for this object.
 452   *
 453   * @return A debugging string for this object.
 454   */
 455 public String
 456 paramString()
 457 {
 458   return ("label=" + label + ",enabled=" + enabled +
 459           ",actionCommand=" + actionCommand + "," + super.paramString());
 460 }
 461
 462 // Accessibility API not yet implemented.
 463 // public AccessibleContext getAccessibleContext()
 464
 465 } // class MenuItem