jmenu.java

gcc的组建

   * @param x x-coordinate of the menu location
   * @param y y-coordinate of the menu location
   */
  public void setMenuLocation(int x, int y)
  {
    menuLocation = new Point(x, y);
  }

  /**
   * Creates and returns JMenuItem associated with the given action
   *
   * @param action Action to use for creation of JMenuItem
   *
   * @return JMenuItem that was creted with given action
   */
  protected JMenuItem createActionComponent(Action action)
  {
    return new JMenuItem(action);
  }

  /**
   * Creates ActionChangeListener to listen for PropertyChangeEvents occuring
   * in the action that is associated with this menu
   *
   * @param item menu that contains action to listen to
   *
   * @return The PropertyChangeListener
   */
  protected PropertyChangeListener createActionChangeListener(JMenuItem item)
  {
    return new ActionChangedListener(item);
  }

  /**
   * Adds separator to the end of the menu items in the menu.
   */
  public void addSeparator()
  {
    getPopupMenu().addSeparator();
  }

  /**
   * Inserts separator in the menu at the specified index.
   *
   * @param index Index at which separator should be inserted
   */
  public void insertSeparator(int index)
  {
    if (index < 0)
      throw new IllegalArgumentException("index less than 0");

    getPopupMenu().insert(new JPopupMenu.Separator(), index);
  }

  /**
   * Returns menu item located at the specified index in the menu
   *
   * @param index Index at which to look for the menu item
   *
   * @return menu item located at the specified index in the menu
   */
  public JMenuItem getItem(int index)
  {
    if (index < 0)
      throw new IllegalArgumentException("index less than 0");

    Component c = popupMenu.getComponentAtIndex(index);

    if (c instanceof JMenuItem)
      return (JMenuItem) c;
    else
      return null;
  }

  /**
   * Returns number of items in the menu including separators.
   *
   * @return number of items in the menu
   *
   * @see #getMenuComponentCount()
   */
  public int getItemCount()
  {
    return getMenuComponentCount();
  }

  /**
   * Checks if this menu is a tear-off menu.
   *
   * @return true if this menu is a tear-off menu and false otherwise
   */
  public boolean isTearOff()
  {
    // NOT YET IMPLEMENTED 
    return false;
  }

  /**
   * Returns number of menu components in this menu
   *
   * @return number of menu components in this menu
   */
  public int getMenuComponentCount()
  {
    return popupMenu.getComponentCount();
  }

  /**
   * Returns menu component located at the givent index
   * in the menu
   *
   * @param index index at which to get the menu component in the menu
   *
   * @return Menu Component located in the menu at the specified index
   */
  public Component getMenuComponent(int index)
  {
    return (Component) popupMenu.getComponentAtIndex(index);
  }

  /**
   * Return components belonging to this menu
   *
   * @return components belonging to this menu
   */
  public Component[] getMenuComponents()
  {
    return popupMenu.getComponents();
  }

  /**
   * Checks if this menu is a top level menu. The menu is top
   * level menu if it is inside the menu bar. While if the menu
   * inside some other menu, it is considered to be a pull-right menu.
   *
   * @return true if this menu is top level menu, and false otherwise
   */
  public boolean isTopLevelMenu()
  {
    return getParent() instanceof JMenuBar;
  }

  /**
   * Checks if given component exists in this menu. The submenus of
   * this menu are checked as well
   *
   * @param component Component to look for
   *
   * @return true if the given component exists in this menu, and false otherwise
   */
  public boolean isMenuComponent(Component component)
  {
    return false;
  }

  /**
   * Returns popup menu associated with the menu.
   *
   * @return popup menu associated with the menu.
   */
  public JPopupMenu getPopupMenu()
  {
    return popupMenu;
  }

  /**
   * Adds MenuListener to the menu
   *
   * @param listener MenuListener to add
   */
  public void addMenuListener(MenuListener listener)
  {
    listenerList.add(MenuListener.class, listener);
  }

  /**
   * Removes MenuListener from the menu
   *
   * @param listener MenuListener to remove
   */
  public void removeMenuListener(MenuListener listener)
  {
    listenerList.remove(MenuListener.class, listener);
  }

  /**
   * Returns all registered <code>MenuListener</code> objects.
   *
   * @return an array of listeners
   * 
   * @since 1.4
   */
  public MenuListener[] getMenuListeners()
  {
    return (MenuListener[]) listenerList.getListeners(MenuListener.class);
  }

  /**
   * This method fires MenuEvents to all menu's MenuListeners. In this case
   * menuSelected() method of MenuListeners is called to indicated that the menu
   * was selected.
   */
  protected void fireMenuSelected()
  {
    MenuListener[] listeners = getMenuListeners();

    for (int index = 0; index < listeners.length; ++index)
      listeners[index].menuSelected(menuEvent);
  }

  /**
   * This method fires MenuEvents to all menu's MenuListeners. In this case
   * menuDeselected() method of MenuListeners is called to indicated that the menu
   * was deselected.
   */
  protected void fireMenuDeselected()
  {
    EventListener[] ll = listenerList.getListeners(MenuListener.class);

    for (int i = 0; i < ll.length; i++)
      ((MenuListener) ll[i]).menuDeselected(menuEvent);
  }

  /**
   * This method fires MenuEvents to all menu's MenuListeners. In this case
   * menuSelected() method of MenuListeners is called to indicated that the menu
   * was cancelled. The menu is cancelled when it's popup menu is close without selection.
   */
  protected void fireMenuCanceled()
  {
    EventListener[] ll = listenerList.getListeners(MenuListener.class);

    for (int i = 0; i < ll.length; i++)
      ((MenuListener) ll[i]).menuCanceled(menuEvent);
  }

  /**
   * Creates WinListener that listens to the menu;s popup menu.
   *
   * @param popup JPopupMenu to listen to
   *
   * @return The WinListener
   */
  protected WinListener createWinListener(JPopupMenu popup)
  {
    return new WinListener(popup);
  }

  /**
   * Method of the MenuElementInterface. It reacts to the selection
   * changes in the menu. If this menu was selected, then it
   * displayes popup menu associated with it and if this menu was
   * deselected it hides the popup menu.
   *
   * @param changed true if the menu was selected and false otherwise
   */
  public void menuSelectionChanged(boolean changed)
  {
    // if this menu selection is true, then activate this menu and 
    // display popup associated with this menu
    setSelectedHelper(changed, isEnabled(), true);
  }

  /**
   * Method of MenuElement interface. Returns sub components of
   * this menu.
   *
   * @return array containing popupMenu that is associated with this menu
   */
  public MenuElement[] getSubElements()
  {
    return new MenuElement[] { popupMenu };
  }

  /**
   * @return Returns reference to itself
   */
  public Component getComponent()
  {
    return this;
  }

  /**
   * This method is overriden with empty implementation, s.t the
   * accelerator couldn't be set for the menu. The mnemonic should
   * be used for the menu instead.
   *
   * @param keystroke accelerator for this menu
   */
  public void setAccelerator(KeyStroke keystroke)
  {
    throw new Error("setAccelerator() is not defined for JMenu.  Use setMnemonic() instead.");
  }

  /**
   * This method process KeyEvent occuring when the menu is visible
   *
   * @param event The KeyEvent
   */
  protected void processKeyEvent(KeyEvent event)
  {
    // TODO: Implement this properly.
  }

  /**
   * Programatically performs click
   *
   * @param time Number of milliseconds for which this menu stays pressed
   */
  public void doClick(int time)
  {
    getModel().setArmed(true);
    getModel().setPressed(true);
    try
      {
	java.lang.Thread.sleep(time);
      }
    catch (java.lang.InterruptedException e)
      {
	// probably harmless
      }

    getModel().setPressed(false);
    getModel().setArmed(false);
    popupMenu.show(this, this.getWidth(), 0);
  }

  /**
   * A string that describes this JMenu. Normally only used
   * for debugging.
   *
   * @return A string describing this JMenu
   */
  protected String paramString()
  {
    return super.paramString();
  }

  public AccessibleContext getAccessibleContext()
  {
    if (accessibleContext == null)
      accessibleContext = new AccessibleJMenu();

    return accessibleContext;
  }

  // FIXME: This inner class is a complete stub and needs to be implemented.
  protected class AccessibleJMenu extends AccessibleJMenuItem
    implements AccessibleSelection
  {
    private static final long serialVersionUID = -8131864021059524309L;

    protected AccessibleJMenu()
    {
      // Nothing to do here.
    }

    public int getAccessibleChildrenCount()
    {
      return 0;
    }

    public Accessible getAccessibleChild(int value0)
    {
      return null;
    }

    public AccessibleSelection getAccessibleSelection()
    {
      return null;
    }

    public Accessible getAccessibleSelection(int value0)
    {
      return null;
    }

    public boolean isAccessibleChildSelected(int value0)
    {
      return false;
    }

    public AccessibleRole getAccessibleRole()
    {
      return AccessibleRole.MENU;
    }

    public int getAccessibleSelectionCount()
    {
      return 0;
    }

    public void addAccessibleSelection(int value0)
    {
      // TODO: Implement this properly.
    }

    public void removeAccessibleSelection(int value0)
    {
      // TODO: Implement this properly.
    }

    public void clearAccessibleSelection()
    {
      // TODO: Implement this properly.
    }

    public void selectAllAccessibleSelection()
    {
      // TODO: Implement this properly.
    }
  }

  protected class WinListener extends WindowAdapter implements Serializable
  {
    private static final long serialVersionUID = -6415815570638474823L;

    /**
     * Creates a new <code>WinListener</code>.
     *
     * @param popup the popup menu which is observed
     */
    public WinListener(JPopupMenu popup)
    {
      // TODO: What should we do with the popup argument?
    }

    /**
     * Receives notification when the popup menu is closing and deselects
     * the menu.
     *
     * @param event the window event
     */
    public void windowClosing(WindowEvent event)
    {
      setSelected(false);
    }
  }

  /**
   * This class listens to PropertyChangeEvents occuring in menu's action
   */
  protected class ActionChangedListener implements PropertyChangeListener
  {
    /** menu item associated with the action */
    private JMenuItem menuItem;

    /** Creates new ActionChangedListener and adds it to menuItem's action */
    public ActionChangedListener(JMenuItem menuItem)
    {
      this.menuItem = menuItem;

      Action a = menuItem.getAction();
      if (a != null)
	a.addPropertyChangeListener(this);
    }

    /**This method is invoked when some change occures in menuItem's action*/
    public void propertyChange(PropertyChangeEvent evt)
    {
      // FIXME: Need to implement
    }
  }

}