Back to index...

	/*
	* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.swing;

	import java.awt.AWTEvent;
	import java.awt.Component;
	import java.awt.ComponentOrientation;
	import java.awt.Container;
	import java.awt.Dimension;
	import java.awt.Frame;
	import java.awt.Graphics;
	import java.awt.GraphicsConfiguration;
	import java.awt.GraphicsDevice;
	import java.awt.GraphicsEnvironment;
	import java.awt.Insets;
	import java.awt.Point;
	import java.awt.Polygon;
	import java.awt.Rectangle;
	import java.awt.Toolkit;
	import java.awt.event.*;
	import java.beans.*;

	import java.util.*;

	import java.io.Serializable;
	import java.io.ObjectOutputStream;
	import java.io.ObjectInputStream;
	import java.io.IOException;

	import javax.swing.event.*;
	import javax.swing.plaf.*;
	import javax.swing.plaf.basic.*;
	import javax.accessibility.*;

	import java.lang.ref.WeakReference;

	/**
	* An implementation of a menu -- a popup window containing
	* <code>JMenuItem</code>s that
	* is displayed when the user selects an item on the <code>JMenuBar</code>.
	* In addition to <code>JMenuItem</code>s, a <code>JMenu</code> can
	* also contain <code>JSeparator</code>s.
	* <p>
	* In essence, a menu is a button with an associated <code>JPopupMenu</code>.
	* When the "button" is pressed, the <code>JPopupMenu</code> appears. If the
	* "button" is on the <code>JMenuBar</code>, the menu is a top-level window.
	* If the "button" is another menu item, then the <code>JPopupMenu</code> is
	* "pull-right" menu.
	* <p>
	* Menus can be configured, and to some degree controlled, by
	* <code><a href="Action.html">Action</a></code>s. Using an
	* <code>Action</code> with a menu has many benefits beyond directly
	* configuring a menu. Refer to <a href="Action.html#buttonActions">
	* Swing Components Supporting <code>Action</code></a> for more
	* details, and you can find more information in <a
	* href="https://docs.oracle.com/javase/tutorial/uiswing/misc/action.html">How
	* to Use Actions</a>, a section in <em>The Java Tutorial</em>.
	* <p>
	* For information and examples of using menus see
	* <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
	* a section in <em>The Java Tutorial.</em>
	* <p>
	* <strong>Warning:</strong> Swing is not thread safe. For more
	* information see <a
	* href="package-summary.html#threading">Swing's Threading
	* Policy</a>.
	* <p>
	* <strong>Warning:</strong>
	* Serialized objects of this class will not be compatible with
	* future Swing releases. The current serialization support is
	* appropriate for short term storage or RMI between applications running
	* the same version of Swing. As of 1.4, support for long term storage
	* of all JavaBeans™
	* has been added to the <code>java.beans</code> package.
	* Please see {@link java.beans.XMLEncoder}.
	*
	* @beaninfo
	* attribute: isContainer true
	* description: A popup window containing menu items displayed in a menu bar.
	*
	* @author Georges Saab
	* @author David Karlton
	* @author Arnaud Weber
	* @see JMenuItem
	* @see JSeparator
	* @see JMenuBar
	* @see JPopupMenu
	*/
	@SuppressWarnings("serial")
	public class JMenu extends JMenuItem implements Accessible,MenuElement
	{
	/**
	* @see #getUIClassID
	* @see #readObject
	*/
	private static final String uiClassID = "MenuUI";

	/*
	* The popup menu portion of the menu.
	*/
	private JPopupMenu popupMenu;

	/*
	* The button's model listeners. Default is <code>null</code>.
	*/
	private ChangeListener menuChangeListener = null;

	/*
	* Only one <code>MenuEvent</code> is needed for each menu since the
	* event's only state is the source property. The source of events
	* generated is always "this". Default is <code>null</code>.
	*/
	private MenuEvent menuEvent = null;

	/*
	* Used by the look and feel (L&F) code to handle
	* implementation specific menu behaviors.
	*/
	private int delay;

	/*
	* Location of the popup component. Location is <code>null</code>
	* if it was not customized by <code>setMenuLocation</code>
	*/
	private Point customMenuLocation = null;

	/* Diagnostic aids -- should be false for production builds. */
	private static final boolean TRACE = false; // trace creates and disposes
	private static final boolean VERBOSE = false; // show reuse hits/misses
	private static final boolean DEBUG = false; // show bad params, misc.

	/**
	* Constructs a new <code>JMenu</code> with no text.
	*/
	public JMenu() {
	this("");
	}

	/**
	* Constructs a new <code>JMenu</code> with the supplied string
	* as its text.
	*
	* @param s the text for the menu label
	*/
	public JMenu(String s) {
	super(s);
	}

	/**
	* Constructs a menu whose properties are taken from the
	* <code>Action</code> supplied.
	* @param a an <code>Action</code>
	*
	* @since 1.3
	*/
	public JMenu(Action a) {
	this();
	setAction(a);
	}

	/**
	* Constructs a new <code>JMenu</code> with the supplied string as
	* its text and specified as a tear-off menu or not.
	*
	* @param s the text for the menu label
	* @param b can the menu be torn off (not yet implemented)
	*/
	public JMenu(String s, boolean b) {
	this(s);
	}


	/**
	* Overriden to do nothing. We want JMenu to be focusable, but
	* <code>JMenuItem</code> doesn't want to be, thus we override this
	* do nothing. We don't invoke <code>setFocusable(true)</code> after
	* super's constructor has completed as this has the side effect that
	* <code>JMenu</code> will be considered traversable via the
	* keyboard, which we don't want. Making a Component traversable by
	* the keyboard after invoking <code>setFocusable(true)</code> is OK,
	* as <code>setFocusable</code> is new API
	* and is speced as such, but internally we don't want to use it like
	* this else we change the keyboard traversability.
	*/
	void initFocusability() {
	}

	/**
	* Resets the UI property with a value from the current look and feel.
	*
	* @see JComponent#updateUI
	*/
	public void updateUI() {
	setUI((MenuItemUI)UIManager.getUI(this));

	if ( popupMenu != null )
	{
	popupMenu.setUI((PopupMenuUI)UIManager.getUI(popupMenu));
	}

	}


	/**
	* Returns the name of the L&F class that renders this component.
	*
	* @return the string "MenuUI"
	* @see JComponent#getUIClassID
	* @see UIDefaults#getUI
	*/
	public String getUIClassID() {
	return uiClassID;
	}

	// public void repaint(long tm, int x, int y, int width, int height) {
	// Thread.currentThread().dumpStack();
	// super.repaint(tm,x,y,width,height);
	// }

	/**
	* Sets the data model for the "menu button" -- the label
	* that the user clicks to open or close the menu.
	*
	* @param newModel the <code>ButtonModel</code>
	* @see #getModel
	* @beaninfo
	* description: The menu's model
	* bound: true
	* expert: true
	* hidden: true
	*/
	public void setModel(ButtonModel newModel) {
	ButtonModel oldModel = getModel();

	super.setModel(newModel);

	if (oldModel != null && menuChangeListener != null) {
	oldModel.removeChangeListener(menuChangeListener);
	menuChangeListener = null;
	}

	model = newModel;

	if (newModel != null) {
	menuChangeListener = createMenuChangeListener();
	newModel.addChangeListener(menuChangeListener);
	}
	}

	/**
	* Returns true if the menu is currently selected (highlighted).
	*
	* @return true if the menu is selected, else false
	*/
	public boolean isSelected() {
	return getModel().isSelected();
	}

	/**
	* Sets the selection status of the menu.
	*
	* @param b true to select (highlight) the menu; false to de-select
	* the menu
	* @beaninfo
	* description: When the menu is selected, its popup child is shown.
	* expert: true
	* hidden: true
	*/
	public void setSelected(boolean b) {
	ButtonModel model = getModel();
	boolean oldValue = model.isSelected();

	// TIGER - 4840653
	// Removed code which fired an AccessibleState.SELECTED
	// PropertyChangeEvent since this resulted in two
	// identical events being fired since
	// AbstractButton.fireItemStateChanged also fires the
	// same event. This caused screen readers to speak the
	// name of the item twice.

	if (b != model.isSelected()) {
	getModel().setSelected(b);
	}
	}

	/**
	* Returns true if the menu's popup window is visible.
	*
	* @return true if the menu is visible, else false
	*/
	public boolean isPopupMenuVisible() {
	ensurePopupMenuCreated();
	return popupMenu.isVisible();
	}

	/**
	* Sets the visibility of the menu's popup. If the menu is
	* not enabled, this method will have no effect.
	*
	* @param b a boolean value -- true to make the menu visible,
	* false to hide it
	* @beaninfo
	* description: The popup menu's visibility
	* expert: true
	* hidden: true
	*/
	public void setPopupMenuVisible(boolean b) {
	if (DEBUG) {
	System.out.println("in JMenu.setPopupMenuVisible " + b);
	// Thread.dumpStack();
	}

	boolean isVisible = isPopupMenuVisible();
	if (b != isVisible && (isEnabled() \|\| !b)) {
	ensurePopupMenuCreated();
	if ((b==true) && isShowing()) {
	// Set location of popupMenu (pulldown or pullright)
	Point p = getCustomMenuLocation();
	if (p == null) {
	p = getPopupMenuOrigin();
	}
	getPopupMenu().show(this, p.x, p.y);
	} else {
	getPopupMenu().setVisible(false);
	}
	}
	}

	/**
	* Computes the origin for the <code>JMenu</code>'s popup menu.
	* This method uses Look and Feel properties named
	* <code>Menu.menuPopupOffsetX</code>,
	* <code>Menu.menuPopupOffsetY</code>,
	* <code>Menu.submenuPopupOffsetX</code>, and
	* <code>Menu.submenuPopupOffsetY</code>
	* to adjust the exact location of popup.
	*
	* @return a <code>Point</code> in the coordinate space of the
	* menu which should be used as the origin
	* of the <code>JMenu</code>'s popup menu
	*
	* @since 1.3
	*/
	protected Point getPopupMenuOrigin() {
	int x;
	int y;
	JPopupMenu pm = getPopupMenu();
	// Figure out the sizes needed to caclulate the menu position
	Dimension s = getSize();
	Dimension pmSize = pm.getSize();
	// For the first time the menu is popped up,
	// the size has not yet been initiated
	if (pmSize.width==0) {
	pmSize = pm.getPreferredSize();
	}
	Point position = getLocationOnScreen();
	Toolkit toolkit = Toolkit.getDefaultToolkit();
	GraphicsConfiguration gc = getGraphicsConfiguration();
	Rectangle screenBounds = new Rectangle(toolkit.getScreenSize());
	GraphicsEnvironment ge =
	GraphicsEnvironment.getLocalGraphicsEnvironment();
	GraphicsDevice[] gd = ge.getScreenDevices();
	for(int i = 0; i < gd.length; i++) {
	if(gd[i].getType() == GraphicsDevice.TYPE_RASTER_SCREEN) {
	GraphicsConfiguration dgc =
	gd[i].getDefaultConfiguration();
	if(dgc.getBounds().contains(position)) {
	gc = dgc;
	break;
	}
	}
	}


	if (gc != null) {
	screenBounds = gc.getBounds();
	// take screen insets (e.g. taskbar) into account
	Insets screenInsets = toolkit.getScreenInsets(gc);

	screenBounds.width -=
	Math.abs(screenInsets.left + screenInsets.right);
	screenBounds.height -=
	Math.abs(screenInsets.top + screenInsets.bottom);
	position.x -= Math.abs(screenInsets.left);
	position.y -= Math.abs(screenInsets.top);
	}

	Container parent = getParent();
	if (parent instanceof JPopupMenu) {
	// We are a submenu (pull-right)
	int xOffset = UIManager.getInt("Menu.submenuPopupOffsetX");
	int yOffset = UIManager.getInt("Menu.submenuPopupOffsetY");

	if( SwingUtilities.isLeftToRight(this) ) {
	// First determine x:
	x = s.width + xOffset; // Prefer placement to the right
	if (position.x + x + pmSize.width >= screenBounds.width
	+ screenBounds.x &&
	// popup doesn't fit - place it wherever there's more room
	screenBounds.width - s.width < 2*(position.x
	- screenBounds.x)) {

	x = 0 - xOffset - pmSize.width;
	}
	} else {
	// First determine x:
	x = 0 - xOffset - pmSize.width; // Prefer placement to the left
	if (position.x + x < screenBounds.x &&
	// popup doesn't fit - place it wherever there's more room
	screenBounds.width - s.width > 2*(position.x -
	screenBounds.x)) {

	x = s.width + xOffset;
	}
	}
	// Then the y:
	y = yOffset; // Prefer dropping down
	if (position.y + y + pmSize.height >= screenBounds.height
	+ screenBounds.y &&
	// popup doesn't fit - place it wherever there's more room
	screenBounds.height - s.height < 2*(position.y
	- screenBounds.y)) {

	y = s.height - yOffset - pmSize.height;
	}
	} else {
	// We are a toplevel menu (pull-down)
	int xOffset = UIManager.getInt("Menu.menuPopupOffsetX");
	int yOffset = UIManager.getInt("Menu.menuPopupOffsetY");

	if( SwingUtilities.isLeftToRight(this) ) {
	// First determine the x:
	x = xOffset; // Extend to the right
	if (position.x + x + pmSize.width >= screenBounds.width
	+ screenBounds.x &&
	// popup doesn't fit - place it wherever there's more room
	screenBounds.width - s.width < 2*(position.x
	- screenBounds.x)) {

	x = s.width - xOffset - pmSize.width;
	}
	} else {
	// First determine the x:
	x = s.width - xOffset - pmSize.width; // Extend to the left
	if (position.x + x < screenBounds.x &&
	// popup doesn't fit - place it wherever there's more room
	screenBounds.width - s.width > 2*(position.x
	- screenBounds.x)) {

	x = xOffset;
	}
	}
	// Then the y:
	y = s.height + yOffset; // Prefer dropping down
	if (position.y + y + pmSize.height >= screenBounds.height
	+ screenBounds.y &&
	// popup doesn't fit - place it wherever there's more room
	screenBounds.height - s.height < 2*(position.y
	- screenBounds.y)) {

	y = 0 - yOffset - pmSize.height; // Otherwise drop 'up'
	}
	}
	return new Point(x,y);
	}


	/**
	* Returns the suggested delay, in milliseconds, before submenus
	* are popped up or down.
	* Each look and feel (L&F) may determine its own policy for
	* observing the <code>delay</code> property.
	* In most cases, the delay is not observed for top level menus
	* or while dragging. The default for <code>delay</code> is 0.
	* This method is a property of the look and feel code and is used
	* to manage the idiosyncrasies of the various UI implementations.
	*
	*
	* @return the <code>delay</code> property
	*/
	public int getDelay() {
	return delay;
	}

	/**
	* Sets the suggested delay before the menu's <code>PopupMenu</code>
	* is popped up or down. Each look and feel (L&F) may determine
	* it's own policy for observing the delay property. In most cases,
	* the delay is not observed for top level menus or while dragging.
	* This method is a property of the look and feel code and is used
	* to manage the idiosyncrasies of the various UI implementations.
	*
	* @param d the number of milliseconds to delay
	* @exception IllegalArgumentException if <code>d</code>
	* is less than 0
	* @beaninfo
	* description: The delay between menu selection and making the popup menu visible
	* expert: true
	*/
	public void setDelay(int d) {
	if (d < 0)
	throw new IllegalArgumentException("Delay must be a positive integer");

	delay = d;
	}

	/**
	* The window-closing listener for the popup.
	*
	* @see WinListener
	*/
	protected WinListener popupListener;

	private void ensurePopupMenuCreated() {
	if (popupMenu == null) {
	final JMenu thisMenu = this;
	this.popupMenu = new JPopupMenu();
	popupMenu.setInvoker(this);
	popupListener = createWinListener(popupMenu);
	}
	}

	/*
	* Return the customized location of the popup component.
	*/
	private Point getCustomMenuLocation() {
	return customMenuLocation;
	}

	/**
	* Sets the location of the popup component.
	*
	* @param x the x coordinate of the popup's new position
	* @param y the y coordinate of the popup's new position
	*/
	public void setMenuLocation(int x, int y) {
	customMenuLocation = new Point(x, y);
	if (popupMenu != null)
	popupMenu.setLocation(x, y);
	}

	/**
	* Appends a menu item to the end of this menu.
	* Returns the menu item added.
	*
	* @param menuItem the <code>JMenuitem</code> to be added
	* @return the <code>JMenuItem</code> added
	*/
	public JMenuItem add(JMenuItem menuItem) {
	ensurePopupMenuCreated();
	return popupMenu.add(menuItem);
	}

	/**
	* Appends a component to the end of this menu.
	* Returns the component added.
	*
	* @param c the <code>Component</code> to add
	* @return the <code>Component</code> added
	*/
	public Component add(Component c) {
	ensurePopupMenuCreated();
	popupMenu.add(c);
	return c;
	}

	/**
	* Adds the specified component to this container at the given
	* position. If <code>index</code> equals -1, the component will
	* be appended to the end.
	* @param c the <code>Component</code> to add
	* @param index the position at which to insert the component
	* @return the <code>Component</code> added
	* @see #remove
	* @see java.awt.Container#add(Component, int)
	*/
	public Component add(Component c, int index) {
	ensurePopupMenuCreated();
	popupMenu.add(c, index);
	return c;
	}

	/**
	* Creates a new menu item with the specified text and appends
	* it to the end of this menu.
	*
	* @param s the string for the menu item to be added
	*/
	public JMenuItem add(String s) {
	return add(new JMenuItem(s));
	}

	/**
	* Creates a new menu item attached to the specified
	* <code>Action</code> object and appends it to the end of this menu.
	*
	* @param a the <code>Action</code> for the menu item to be added
	* @see Action
	*/
	public JMenuItem add(Action a) {
	JMenuItem mi = createActionComponent(a);
	mi.setAction(a);
	add(mi);
	return mi;
	}

	/**
	* Factory method which creates the <code>JMenuItem</code> for
	* <code>Action</code>s added to the <code>JMenu</code>.
	*
	* @param a the <code>Action</code> for the menu item to be added
	* @return the new menu item
	* @see Action
	*
	* @since 1.3
	*/
	protected JMenuItem createActionComponent(Action a) {
	JMenuItem mi = new JMenuItem() {
	protected PropertyChangeListener createActionPropertyChangeListener(Action a) {
	PropertyChangeListener pcl = createActionChangeListener(this);
	if (pcl == null) {
	pcl = super.createActionPropertyChangeListener(a);
	}
	return pcl;
	}
	};
	mi.setHorizontalTextPosition(JButton.TRAILING);
	mi.setVerticalTextPosition(JButton.CENTER);
	return mi;
	}

	/**
	* Returns a properly configured <code>PropertyChangeListener</code>
	* which updates the control as changes to the <code>Action</code> occur.
	*/
	protected PropertyChangeListener createActionChangeListener(JMenuItem b) {
	return b.createActionPropertyChangeListener0(b.getAction());
	}

	/**
	* Appends a new separator to the end of the menu.
	*/
	public void addSeparator()
	{
	ensurePopupMenuCreated();
	popupMenu.addSeparator();
	}

	/**
	* Inserts a new menu item with the specified text at a
	* given position.
	*
	* @param s the text for the menu item to add
	* @param pos an integer specifying the position at which to add the
	* new menu item
	* @exception IllegalArgumentException when the value of
	* <code>pos</code> < 0
	*/
	public void insert(String s, int pos) {
	if (pos < 0) {
	throw new IllegalArgumentException("index less than zero.");
	}

	ensurePopupMenuCreated();
	popupMenu.insert(new JMenuItem(s), pos);
	}

	/**
	* Inserts the specified <code>JMenuitem</code> at a given position.
	*
	* @param mi the <code>JMenuitem</code> to add
	* @param pos an integer specifying the position at which to add the
	* new <code>JMenuitem</code>
	* @return the new menu item
	* @exception IllegalArgumentException if the value of
	* <code>pos</code> < 0
	*/
	public JMenuItem insert(JMenuItem mi, int pos) {
	if (pos < 0) {
	throw new IllegalArgumentException("index less than zero.");
	}
	ensurePopupMenuCreated();
	popupMenu.insert(mi, pos);
	return mi;
	}

	/**
	* Inserts a new menu item attached to the specified <code>Action</code>
	* object at a given position.
	*
	* @param a the <code>Action</code> object for the menu item to add
	* @param pos an integer specifying the position at which to add the
	* new menu item
	* @exception IllegalArgumentException if the value of
	* <code>pos</code> < 0
	*/
	public JMenuItem insert(Action a, int pos) {
	if (pos < 0) {
	throw new IllegalArgumentException("index less than zero.");
	}

	ensurePopupMenuCreated();
	JMenuItem mi = new JMenuItem(a);
	mi.setHorizontalTextPosition(JButton.TRAILING);
	mi.setVerticalTextPosition(JButton.CENTER);
	popupMenu.insert(mi, pos);
	return mi;
	}

	/**
	* Inserts a separator at the specified position.
	*
	* @param index an integer specifying the position at which to
	* insert the menu separator
	* @exception IllegalArgumentException if the value of
	* <code>index</code> < 0
	*/
	public void insertSeparator(int index) {
	if (index < 0) {
	throw new IllegalArgumentException("index less than zero.");
	}

	ensurePopupMenuCreated();
	popupMenu.insert( new JPopupMenu.Separator(), index );
	}

	/**
	* Returns the <code>JMenuItem</code> at the specified position.
	* If the component at <code>pos</code> is not a menu item,
	* <code>null</code> is returned.
	* This method is included for AWT compatibility.
	*
	* @param pos an integer specifying the position
	* @exception IllegalArgumentException if the value of
	* <code>pos</code> < 0
	* @return the menu item at the specified position; or <code>null</code>
	* if the item as the specified position is not a menu item
	*/
	public JMenuItem getItem(int pos) {
	if (pos < 0) {
	throw new IllegalArgumentException("index less than zero.");
	}

	Component c = getMenuComponent(pos);
	if (c instanceof JMenuItem) {
	JMenuItem mi = (JMenuItem) c;
	return mi;
	}

	// 4173633
	return null;
	}

	/**
	* Returns the number of items on the menu, including separators.
	* This method is included for AWT compatibility.
	*
	* @return an integer equal to the number of items on the menu
	* @see #getMenuComponentCount
	*/
	public int getItemCount() {
	return getMenuComponentCount();
	}

	/**
	* Returns true if the menu can be torn off. This method is not
	* yet implemented.
	*
	* @return true if the menu can be torn off, else false
	* @exception Error if invoked -- this method is not yet implemented
	*/
	public boolean isTearOff() {
	throw new Error("boolean isTearOff() {} not yet implemented");
	}

	/**
	* Removes the specified menu item from this menu. If there is no
	* popup menu, this method will have no effect.
	*
	* @param item the <code>JMenuItem</code> to be removed from the menu
	*/
	public void remove(JMenuItem item) {
	if (popupMenu != null)
	popupMenu.remove(item);
	}

	/**
	* Removes the menu item at the specified index from this menu.
	*
	* @param pos the position of the item to be removed
	* @exception IllegalArgumentException if the value of
	* <code>pos</code> < 0, or if <code>pos</code>
	* is greater than the number of menu items
	*/
	public void remove(int pos) {
	if (pos < 0) {
	throw new IllegalArgumentException("index less than zero.");
	}
	if (pos > getItemCount()) {
	throw new IllegalArgumentException("index greater than the number of items.");
	}
	if (popupMenu != null)
	popupMenu.remove(pos);
	}

	/**
	* Removes the component <code>c</code> from this menu.
	*
	* @param c the component to be removed
	*/
	public void remove(Component c) {
	if (popupMenu != null)
	popupMenu.remove(c);
	}

	/**
	* Removes all menu items from this menu.
	*/
	public void removeAll() {
	if (popupMenu != null)
	popupMenu.removeAll();
	}

	/**
	* Returns the number of components on the menu.
	*
	* @return an integer containing the number of components on the menu
	*/
	public int getMenuComponentCount() {
	int componentCount = 0;
	if (popupMenu != null)
	componentCount = popupMenu.getComponentCount();
	return componentCount;
	}

	/**
	* Returns the component at position <code>n</code>.
	*
	* @param n the position of the component to be returned
	* @return the component requested, or <code>null</code>
	* if there is no popup menu
	*
	*/
	public Component getMenuComponent(int n) {
	if (popupMenu != null)
	return popupMenu.getComponent(n);

	return null;
	}

	/**
	* Returns an array of <code>Component</code>s of the menu's
	* subcomponents. Note that this returns all <code>Component</code>s
	* in the popup menu, including separators.
	*
	* @return an array of <code>Component</code>s or an empty array
	* if there is no popup menu
	*/
	public Component[] getMenuComponents() {
	if (popupMenu != null)
	return popupMenu.getComponents();

	return new Component[0];
	}

	/**
	* Returns true if the menu is a 'top-level menu', that is, if it is
	* the direct child of a menubar.
	*
	* @return true if the menu is activated from the menu bar;
	* false if the menu is activated from a menu item
	* on another menu
	*/
	public boolean isTopLevelMenu() {
	return getParent() instanceof JMenuBar;

	}

	/**
	* Returns true if the specified component exists in the
	* submenu hierarchy.
	*
	* @param c the <code>Component</code> to be tested
	* @return true if the <code>Component</code> exists, false otherwise
	*/
	public boolean isMenuComponent(Component c) {
	// Are we in the MenuItem part of the menu
	if (c == this)
	return true;
	// Are we in the PopupMenu?
	if (c instanceof JPopupMenu) {
	JPopupMenu comp = (JPopupMenu) c;
	if (comp == this.getPopupMenu())
	return true;
	}
	// Are we in a Component on the PopupMenu
	int ncomponents = this.getMenuComponentCount();
	Component[] component = this.getMenuComponents();
	for (int i = 0 ; i < ncomponents ; i++) {
	Component comp = component[i];
	// Are we in the current component?
	if (comp == c)
	return true;
	// Hmmm, what about Non-menu containers?

	// Recursive call for the Menu case
	if (comp instanceof JMenu) {
	JMenu subMenu = (JMenu) comp;
	if (subMenu.isMenuComponent(c))
	return true;
	}
	}
	return false;
	}


	/*
	* Returns a point in the coordinate space of this menu's popupmenu
	* which corresponds to the point <code>p</code> in the menu's
	* coordinate space.
	*
	* @param p the point to be translated
	* @return the point in the coordinate space of this menu's popupmenu
	*/
	private Point translateToPopupMenu(Point p) {
	return translateToPopupMenu(p.x, p.y);
	}

	/*
	* Returns a point in the coordinate space of this menu's popupmenu
	* which corresponds to the point (x,y) in the menu's coordinate space.
	*
	* @param x the x coordinate of the point to be translated
	* @param y the y coordinate of the point to be translated
	* @return the point in the coordinate space of this menu's popupmenu
	*/
	private Point translateToPopupMenu(int x, int y) {
	int newX;
	int newY;

	if (getParent() instanceof JPopupMenu) {
	newX = x - getSize().width;
	newY = y;
	} else {
	newX = x;
	newY = y - getSize().height;
	}

	return new Point(newX, newY);
	}

	/**
	* Returns the popupmenu associated with this menu. If there is
	* no popupmenu, it will create one.
	*/
	public JPopupMenu getPopupMenu() {
	ensurePopupMenuCreated();
	return popupMenu;
	}

	/**
	* Adds a listener for menu events.
	*
	* @param l the listener to be added
	*/
	public void addMenuListener(MenuListener l) {
	listenerList.add(MenuListener.class, l);
	}

	/**
	* Removes a listener for menu events.
	*
	* @param l the listener to be removed
	*/
	public void removeMenuListener(MenuListener l) {
	listenerList.remove(MenuListener.class, l);
	}

	/**
	* Returns an array of all the <code>MenuListener</code>s added
	* to this JMenu with addMenuListener().
	*
	* @return all of the <code>MenuListener</code>s added or an empty
	* array if no listeners have been added
	* @since 1.4
	*/
	public MenuListener[] getMenuListeners() {
	return listenerList.getListeners(MenuListener.class);
	}

	/**
	* Notifies all listeners that have registered interest for
	* notification on this event type. The event instance
	* is created lazily.
	*
	* @exception Error if there is a <code>null</code> listener
	* @see EventListenerList
	*/
	protected void fireMenuSelected() {
	if (DEBUG) {
	System.out.println("In JMenu.fireMenuSelected");
	}
	// Guaranteed to return a non-null array
	Object[] listeners = listenerList.getListenerList();
	// Process the listeners last to first, notifying
	// those that are interested in this event
	for (int i = listeners.length-2; i>=0; i-=2) {
	if (listeners[i]==MenuListener.class) {
	if (listeners[i+1]== null) {
	throw new Error(getText() +" has a NULL Listener!! " + i);
	} else {
	// Lazily create the event:
	if (menuEvent == null)
	menuEvent = new MenuEvent(this);
	((MenuListener)listeners[i+1]).menuSelected(menuEvent);
	}
	}
	}
	}

	/**
	* Notifies all listeners that have registered interest for
	* notification on this event type. The event instance
	* is created lazily.
	*
	* @exception Error if there is a <code>null</code> listener
	* @see EventListenerList
	*/
	protected void fireMenuDeselected() {
	if (DEBUG) {
	System.out.println("In JMenu.fireMenuDeselected");
	}
	// Guaranteed to return a non-null array
	Object[] listeners = listenerList.getListenerList();
	// Process the listeners last to first, notifying
	// those that are interested in this event
	for (int i = listeners.length-2; i>=0; i-=2) {
	if (listeners[i]==MenuListener.class) {
	if (listeners[i+1]== null) {
	throw new Error(getText() +" has a NULL Listener!! " + i);
	} else {
	// Lazily create the event:
	if (menuEvent == null)
	menuEvent = new MenuEvent(this);
	((MenuListener)listeners[i+1]).menuDeselected(menuEvent);
	}
	}
	}
	}

	/**
	* Notifies all listeners that have registered interest for
	* notification on this event type. The event instance
	* is created lazily.
	*
	* @exception Error if there is a <code>null</code> listener
	* @see EventListenerList
	*/
	protected void fireMenuCanceled() {
	if (DEBUG) {
	System.out.println("In JMenu.fireMenuCanceled");
	}
	// Guaranteed to return a non-null array
	Object[] listeners = listenerList.getListenerList();
	// Process the listeners last to first, notifying
	// those that are interested in this event
	for (int i = listeners.length-2; i>=0; i-=2) {
	if (listeners[i]==MenuListener.class) {
	if (listeners[i+1]== null) {
	throw new Error(getText() +" has a NULL Listener!! "
	+ i);
	} else {
	// Lazily create the event:
	if (menuEvent == null)
	menuEvent = new MenuEvent(this);
	((MenuListener)listeners[i+1]).menuCanceled(menuEvent);
	}
	}
	}
	}

	// Overriden to do nothing, JMenu doesn't support an accelerator
	void configureAcceleratorFromAction(Action a) {
	}

	@SuppressWarnings("serial")
	class MenuChangeListener implements ChangeListener, Serializable {
	boolean isSelected = false;
	public void stateChanged(ChangeEvent e) {
	ButtonModel model = (ButtonModel) e.getSource();
	boolean modelSelected = model.isSelected();

	if (modelSelected != isSelected) {
	if (modelSelected == true) {
	fireMenuSelected();
	} else {
	fireMenuDeselected();
	}
	isSelected = modelSelected;
	}
	}
	}

	private ChangeListener createMenuChangeListener() {
	return new MenuChangeListener();
	}


	/**
	* Creates a window-closing listener for the popup.
	*
	* @param p the <code>JPopupMenu</code>
	* @return the new window-closing listener
	*
	* @see WinListener
	*/
	protected WinListener createWinListener(JPopupMenu p) {
	return new WinListener(p);
	}

	/**
	* A listener class that watches for a popup window closing.
	* When the popup is closing, the listener deselects the menu.
	* <p>
	* <strong>Warning:</strong>
	* Serialized objects of this class will not be compatible with
	* future Swing releases. The current serialization support is
	* appropriate for short term storage or RMI between applications running
	* the same version of Swing. As of 1.4, support for long term storage
	* of all JavaBeans™
	* has been added to the <code>java.beans</code> package.
	* Please see {@link java.beans.XMLEncoder}.
	*/
	@SuppressWarnings("serial")
	protected class WinListener extends WindowAdapter implements Serializable {
	JPopupMenu popupMenu;
	/**
	* Create the window listener for the specified popup.
	* @since 1.4
	*/
	public WinListener(JPopupMenu p) {
	this.popupMenu = p;
	}
	/**
	* Deselect the menu when the popup is closed from outside.
	*/
	public void windowClosing(WindowEvent e) {
	setSelected(false);
	}
	}

	/**
	* Messaged when the menubar selection changes to activate or
	* deactivate this menu.
	* Overrides <code>JMenuItem.menuSelectionChanged</code>.
	*
	* @param isIncluded true if this menu is active, false if
	* it is not
	*/
	public void menuSelectionChanged(boolean isIncluded) {
	if (DEBUG) {
	System.out.println("In JMenu.menuSelectionChanged to " + isIncluded);
	}
	setSelected(isIncluded);
	}

	/**
	* Returns an array of <code>MenuElement</code>s containing the submenu
	* for this menu component. If popup menu is <code>null</code> returns
	* an empty array. This method is required to conform to the
	* <code>MenuElement</code> interface. Note that since
	* <code>JSeparator</code>s do not conform to the <code>MenuElement</code>
	* interface, this array will only contain <code>JMenuItem</code>s.
	*
	* @return an array of <code>MenuElement</code> objects
	*/
	public MenuElement[] getSubElements() {
	if(popupMenu == null)
	return new MenuElement[0];
	else {
	MenuElement result[] = new MenuElement[1];
	result[0] = popupMenu;
	return result;
	}
	}


	// implements javax.swing.MenuElement
	/**
	* Returns the <code>java.awt.Component</code> used to
	* paint this <code>MenuElement</code>.
	* The returned component is used to convert events and detect if
	* an event is inside a menu component.
	*/
	public Component getComponent() {
	return this;
	}


	/**
	* Sets the <code>ComponentOrientation</code> property of this menu
	* and all components contained within it. This includes all
	* components returned by {@link #getMenuComponents getMenuComponents}.
	*
	* @param o the new component orientation of this menu and
	* the components contained within it.
	* @exception NullPointerException if <code>orientation</code> is null.
	* @see java.awt.Component#setComponentOrientation
	* @see java.awt.Component#getComponentOrientation
	* @since 1.4
	*/
	public void applyComponentOrientation(ComponentOrientation o) {
	super.applyComponentOrientation(o);

	if ( popupMenu != null ) {
	int ncomponents = getMenuComponentCount();
	for (int i = 0 ; i < ncomponents ; ++i) {
	getMenuComponent(i).applyComponentOrientation(o);
	}
	popupMenu.setComponentOrientation(o);
	}
	}

	public void setComponentOrientation(ComponentOrientation o) {
	super.setComponentOrientation(o);
	if ( popupMenu != null ) {
	popupMenu.setComponentOrientation(o);
	}
	}

	/**
	* <code>setAccelerator</code> is not defined for <code>JMenu</code>.
	* Use <code>setMnemonic</code> instead.
	* @param keyStroke the keystroke combination which will invoke
	* the <code>JMenuItem</code>'s actionlisteners
	* without navigating the menu hierarchy
	* @exception Error if invoked -- this method is not defined for JMenu.
	* Use <code>setMnemonic</code> instead
	*
	* @beaninfo
	* description: The keystroke combination which will invoke the JMenuItem's
	* actionlisteners without navigating the menu hierarchy
	* hidden: true
	*/
	public void setAccelerator(KeyStroke keyStroke) {
	throw new Error("setAccelerator() is not defined for JMenu. Use setMnemonic() instead.");
	}

	/**
	* Processes key stroke events such as mnemonics and accelerators.
	*
	* @param evt the key event to be processed
	*/
	protected void processKeyEvent(KeyEvent evt) {
	MenuSelectionManager.defaultManager().processKeyEvent(evt);
	if (evt.isConsumed())
	return;

	super.processKeyEvent(evt);
	}

	/**
	* Programmatically performs a "click". This overrides the method
	* <code>AbstractButton.doClick</code> in order to make the menu pop up.
	* @param pressTime indicates the number of milliseconds the
	* button was pressed for
	*/
	public void doClick(int pressTime) {
	MenuElement me[] = buildMenuElementArray(this);
	MenuSelectionManager.defaultManager().setSelectedPath(me);
	}

	/*
	* Build an array of menu elements - from <code>PopupMenu</code> to
	* the root <code>JMenuBar</code>.
	* @param leaf the leaf node from which to start building up the array
	* @return the array of menu items
	*/
	private MenuElement[] buildMenuElementArray(JMenu leaf) {
	Vector<MenuElement> elements = new Vector<MenuElement>();
	Component current = leaf.getPopupMenu();
	JPopupMenu pop;
	JMenu menu;
	JMenuBar bar;

	while (true) {
	if (current instanceof JPopupMenu) {
	pop = (JPopupMenu) current;
	elements.insertElementAt(pop, 0);
	current = pop.getInvoker();
	} else if (current instanceof JMenu) {
	menu = (JMenu) current;
	elements.insertElementAt(menu, 0);
	current = menu.getParent();
	} else if (current instanceof JMenuBar) {
	bar = (JMenuBar) current;
	elements.insertElementAt(bar, 0);
	MenuElement me[] = new MenuElement[elements.size()];
	elements.copyInto(me);
	return me;
	}
	}
	}


	/**
	* See <code>readObject</code> and <code>writeObject</code> in
	* <code>JComponent</code> for more
	* information about serialization in Swing.
	*/
	private void writeObject(ObjectOutputStream s) throws IOException {
	s.defaultWriteObject();
	if (getUIClassID().equals(uiClassID)) {
	byte count = JComponent.getWriteObjCounter(this);
	JComponent.setWriteObjCounter(this, --count);
	if (count == 0 && ui != null) {
	ui.installUI(this);
	}
	}
	}


	/**
	* Returns a string representation of this <code>JMenu</code>. This
	* method is intended to be used only for debugging purposes, and the
	* content and format of the returned string may vary between
	* implementations. The returned string may be empty but may not
	* be <code>null</code>.
	*
	* @return a string representation of this JMenu.
	*/
	protected String paramString() {
	return super.paramString();
	}


	/////////////////
	// Accessibility support
	////////////////

	/**
	* Gets the AccessibleContext associated with this JMenu.
	* For JMenus, the AccessibleContext takes the form of an
	* AccessibleJMenu.
	* A new AccessibleJMenu instance is created if necessary.
	*
	* @return an AccessibleJMenu that serves as the
	* AccessibleContext of this JMenu
	*/
	public AccessibleContext getAccessibleContext() {
	if (accessibleContext == null) {
	accessibleContext = new AccessibleJMenu();
	}
	return accessibleContext;
	}

	/**
	* This class implements accessibility support for the
	* <code>JMenu</code> class. It provides an implementation of the
	* Java Accessibility API appropriate to menu user-interface elements.
	* <p>
	* <strong>Warning:</strong>
	* Serialized objects of this class will not be compatible with
	* future Swing releases. The current serialization support is
	* appropriate for short term storage or RMI between applications running
	* the same version of Swing. As of 1.4, support for long term storage
	* of all JavaBeans™
	* has been added to the <code>java.beans</code> package.
	* Please see {@link java.beans.XMLEncoder}.
	*/
	@SuppressWarnings("serial")
	protected class AccessibleJMenu extends AccessibleJMenuItem
	implements AccessibleSelection {

	/**
	* Returns the number of accessible children in the object. If all
	* of the children of this object implement Accessible, than this
	* method should return the number of children of this object.
	*
	* @return the number of accessible children in the object.
	*/
	public int getAccessibleChildrenCount() {
	Component[] children = getMenuComponents();
	int count = 0;
	for (Component child : children) {
	if (child instanceof Accessible) {
	count++;
	}
	}
	return count;
	}

	/**
	* Returns the nth Accessible child of the object.
	*
	* @param i zero-based index of child
	* @return the nth Accessible child of the object
	*/
	public Accessible getAccessibleChild(int i) {
	Component[] children = getMenuComponents();
	int count = 0;
	for (Component child : children) {
	if (child instanceof Accessible) {
	if (count == i) {
	if (child instanceof JComponent) {
	// FIXME: [[[WDW - probably should set this when
	// the component is added to the menu. I tried
	// to do this in most cases, but the separators
	// added by addSeparator are hard to get to.]]]
	AccessibleContext ac = child.getAccessibleContext();
	ac.setAccessibleParent(JMenu.this);
	}
	return (Accessible) child;
	} else {
	count++;
	}
	}
	}
	return null;
	}

	/**
	* Get the role of this object.
	*
	* @return an instance of AccessibleRole describing the role of the
	* object
	* @see AccessibleRole
	*/
	public AccessibleRole getAccessibleRole() {
	return AccessibleRole.MENU;
	}

	/**
	* Get the AccessibleSelection associated with this object. In the
	* implementation of the Java Accessibility API for this class,
	* return this object, which is responsible for implementing the
	* AccessibleSelection interface on behalf of itself.
	*
	* @return this object
	*/
	public AccessibleSelection getAccessibleSelection() {
	return this;
	}

	/**
	* Returns 1 if a sub-menu is currently selected in this menu.
	*
	* @return 1 if a menu is currently selected, else 0
	*/
	public int getAccessibleSelectionCount() {
	MenuElement me[] =
	MenuSelectionManager.defaultManager().getSelectedPath();
	if (me != null) {
	for (int i = 0; i < me.length; i++) {
	if (me[i] == JMenu.this) { // this menu is selected
	if (i+1 < me.length) {
	return 1;
	}
	}
	}
	}
	return 0;
	}

	/**
	* Returns the currently selected sub-menu if one is selected,
	* otherwise null (there can only be one selection, and it can
	* only be a sub-menu, as otherwise menu items don't remain
	* selected).
	*/
	public Accessible getAccessibleSelection(int i) {
	// if i is a sub-menu & popped, return it
	if (i < 0 \|\| i >= getItemCount()) {
	return null;
	}
	MenuElement me[] =
	MenuSelectionManager.defaultManager().getSelectedPath();
	if (me != null) {
	for (int j = 0; j < me.length; j++) {
	if (me[j] == JMenu.this) { // this menu is selected
	// so find the next JMenuItem in the MenuElement
	// array, and return it!
	while (++j < me.length) {
	if (me[j] instanceof JMenuItem) {
	return (Accessible) me[j];
	}
	}
	}
	}
	}
	return null;
	}

	/**
	* Returns true if the current child of this object is selected
	* (that is, if this child is a popped-up submenu).
	*
	* @param i the zero-based index of the child in this Accessible
	* object.
	* @see AccessibleContext#getAccessibleChild
	*/
	public boolean isAccessibleChildSelected(int i) {
	// if i is a sub-menu and is pop-ed up, return true, else false
	MenuElement me[] =
	MenuSelectionManager.defaultManager().getSelectedPath();
	if (me != null) {
	JMenuItem mi = JMenu.this.getItem(i);
	for (int j = 0; j < me.length; j++) {
	if (me[j] == mi) {
	return true;
	}
	}
	}
	return false;
	}


	/**
	* Selects the <code>i</code>th menu in the menu.
	* If that item is a submenu,
	* it will pop up in response. If a different item is already
	* popped up, this will force it to close. If this is a sub-menu
	* that is already popped up (selected), this method has no
	* effect.
	*
	* @param i the index of the item to be selected
	* @see #getAccessibleStateSet
	*/
	public void addAccessibleSelection(int i) {
	if (i < 0 \|\| i >= getItemCount()) {
	return;
	}
	JMenuItem mi = getItem(i);
	if (mi != null) {
	if (mi instanceof JMenu) {
	MenuElement me[] = buildMenuElementArray((JMenu) mi);
	MenuSelectionManager.defaultManager().setSelectedPath(me);
	} else {
	MenuSelectionManager.defaultManager().setSelectedPath(null);
	}
	}
	}

	/**
	* Removes the nth item from the selection. In general, menus
	* can only have one item within them selected at a time
	* (e.g. one sub-menu popped open).
	*
	* @param i the zero-based index of the selected item
	*/
	public void removeAccessibleSelection(int i) {
	if (i < 0 \|\| i >= getItemCount()) {
	return;
	}
	JMenuItem mi = getItem(i);
	if (mi != null && mi instanceof JMenu) {
	if (mi.isSelected()) {
	MenuElement old[] =
	MenuSelectionManager.defaultManager().getSelectedPath();
	MenuElement me[] = new MenuElement[old.length-2];
	for (int j = 0; j < old.length -2; j++) {
	me[j] = old[j];
	}
	MenuSelectionManager.defaultManager().setSelectedPath(me);
	}
	}
	}

	/**
	* Clears the selection in the object, so that nothing in the
	* object is selected. This will close any open sub-menu.
	*/
	public void clearAccessibleSelection() {
	// if this menu is selected, reset selection to only go
	// to this menu; else do nothing
	MenuElement old[] =
	MenuSelectionManager.defaultManager().getSelectedPath();
	if (old != null) {
	for (int j = 0; j < old.length; j++) {
	if (old[j] == JMenu.this) { // menu is in the selection!
	MenuElement me[] = new MenuElement[j+1];
	System.arraycopy(old, 0, me, 0, j);
	me[j] = JMenu.this.getPopupMenu();
	MenuSelectionManager.defaultManager().setSelectedPath(me);
	}
	}
	}
	}

	/**
	* Normally causes every selected item in the object to be selected
	* if the object supports multiple selections. This method
	* makes no sense in a menu bar, and so does nothing.
	*/
	public void selectAllAccessibleSelection() {
	}
	} // inner class AccessibleJMenu

	}

Back to index...