/*
 * Copyright (c) 1997, 2019, 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
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 */
package javax.swing;

import java.awt.*;
import java.awt.event.*;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.beans.JavaBean;
import java.beans.BeanProperty;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import java.util.Vector;
import javax.accessibility.*;
import javax.swing.plaf.PopupMenuUI;
import javax.swing.plaf.basic.BasicComboPopup;
import javax.swing.event.*;

import sun.awt.SunToolkit;

An implementation of a popup menu -- a small window that pops up
and displays a series of choices. A JPopupMenu is used for the
menu that appears when the user selects an item on the menu bar.
It is also used for "pull-right" menu that appears when the
selects a menu item that activates it. Finally, a JPopupMenu
can also be used anywhere else you want a menu to appear.  For
example, when the user right-clicks in a specified area.

For information and examples of using popup menus, see
How to Use Menus
in The Java Tutorial.

Warning: Swing is not thread safe. For more
information see Swing's Threading
Policy.

Warning:
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 java.beans package. Please see XMLEncoder. 
Author:
Georges Saab, David Karlton, Arnaud Weber
Since:
1.2/**
 * An implementation of a popup menu -- a small window that pops up
 * and displays a series of choices. A <code>JPopupMenu</code> is used for the
 * menu that appears when the user selects an item on the menu bar.
 * It is also used for "pull-right" menu that appears when the
 * selects a menu item that activates it. Finally, a <code>JPopupMenu</code>
 * can also be used anywhere else you want a menu to appear.  For
 * example, when the user right-clicks in a specified area.
 * <p>
 * For information and examples of using popup menus, see
 * <a
 href="http://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>
 * 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&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Georges Saab
 * @author David Karlton
 * @author Arnaud Weber
 * @since 1.2
 */
@JavaBean(defaultProperty = "UI", description = "A small window that pops up and displays a series of choices.")
@SwingContainer(false)
@SuppressWarnings("serial")
public class JPopupMenu extends JComponent implements Accessible,MenuElement {

    
See Also:
getUIClassID
readObject/**
     * @see #getUIClassID
     * @see #readObject
     */
    private static final String uiClassID = "PopupMenuUI";

    
Key used in AppContext to determine if light way popups are the default.
/**
     * Key used in AppContext to determine if light way popups are the default.
     */
    private static final Object defaultLWPopupEnabledKey =
        new StringBuffer("JPopupMenu.defaultLWPopupEnabledKey");

    
Bug#4425878-Property javax.swing.adjustPopupLocationToFit introduced /** Bug#4425878-Property javax.swing.adjustPopupLocationToFit introduced */
    static boolean popupPostionFixDisabled = false;

    static {
        popupPostionFixDisabled = java.security.AccessController.doPrivileged(
                new sun.security.action.GetPropertyAction(
                "javax.swing.adjustPopupLocationToFit","")).equals("false");

    }

    transient  Component invoker;
    transient  Popup popup;
    transient  Frame frame;
    private    int desiredLocationX,desiredLocationY;

    private    String     label                   = null;
    private    boolean   paintBorder              = true;
    private    Insets    margin                   = null;

    
Used to indicate if lightweight popups should be used.
/**
     * Used to indicate if lightweight popups should be used.
     */
    private    boolean   lightWeightPopup         = true;

    /*
     * Model for the selected subcontrol.
     */
    private SingleSelectionModel selectionModel;

    /* Lock object used in place of class object for synchronization.
     * (4187686)
     */
    private static final Object classLock = new Object();

    /* 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.

    
 Sets the default value of the lightWeightPopupEnabled
 property.
 @param aFlag true if popups can be lightweight,
              otherwise false
 @see #getDefaultLightWeightPopupEnabled
 @see #setLightWeightPopupEnabled
/**
     *  Sets the default value of the <code>lightWeightPopupEnabled</code>
     *  property.
     *
     *  @param aFlag <code>true</code> if popups can be lightweight,
     *               otherwise <code>false</code>
     *  @see #getDefaultLightWeightPopupEnabled
     *  @see #setLightWeightPopupEnabled
     */
    public static void setDefaultLightWeightPopupEnabled(boolean aFlag) {
        SwingUtilities.appContextPut(defaultLWPopupEnabledKey,
                                     Boolean.valueOf(aFlag));
    }

    
 Gets the defaultLightWeightPopupEnabled property,
 which by default is true.
 @return the value of the defaultLightWeightPopupEnabled
         property
 @see #setDefaultLightWeightPopupEnabled
/**
     *  Gets the <code>defaultLightWeightPopupEnabled</code> property,
     *  which by default is <code>true</code>.
     *
     *  @return the value of the <code>defaultLightWeightPopupEnabled</code>
     *          property
     *
     *  @see #setDefaultLightWeightPopupEnabled
     */
    public static boolean getDefaultLightWeightPopupEnabled() {
        Boolean b = (Boolean)
            SwingUtilities.appContextGet(defaultLWPopupEnabledKey);
        if (b == null) {
            SwingUtilities.appContextPut(defaultLWPopupEnabledKey,
                                         Boolean.TRUE);
            return true;
        }
        return b.booleanValue();
    }

    
Constructs a JPopupMenu without an "invoker".
/**
     * Constructs a <code>JPopupMenu</code> without an "invoker".
     */
    public JPopupMenu() {
        this(null);
    }

    
Constructs a JPopupMenu with the specified title.
Params:
label –  the string that a UI may use to display as a title
for the popup menu./**
     * Constructs a <code>JPopupMenu</code> with the specified title.
     *
     * @param label  the string that a UI may use to display as a title
     * for the popup menu.
     */
    public JPopupMenu(String label) {
        this.label = label;
        lightWeightPopup = getDefaultLightWeightPopupEnabled();
        setSelectionModel(new DefaultSingleSelectionModel());
        enableEvents(AWTEvent.MOUSE_EVENT_MASK);
        setFocusTraversalKeysEnabled(false);
        updateUI();
    }



    
Returns the look and feel (L&F) object that renders this component.
Returns:
the PopupMenuUI object that renders this component/**
     * Returns the look and feel (L&amp;F) object that renders this component.
     *
     * @return the <code>PopupMenuUI</code> object that renders this component
     */
    public PopupMenuUI getUI() {
        return (PopupMenuUI)ui;
    }

    
Sets the L&F object that renders this component.
Params:
ui – the new PopupMenuUI L&F object
See Also:
UIDefaults.getUI/**
     * Sets the L&amp;F object that renders this component.
     *
     * @param ui the new <code>PopupMenuUI</code> L&amp;F object
     * @see UIDefaults#getUI
     */
    @BeanProperty(hidden = true, visualUpdate = true, description
            = "The UI object that implements the Component's LookAndFeel.")
    public void setUI(PopupMenuUI ui) {
        super.setUI(ui);
    }

    
Resets the UI property to a value from the current look and feel.
See Also:
updateUI.updateUI/**
     * Resets the UI property to a value from the current look and feel.
     *
     * @see JComponent#updateUI
     */
    public void updateUI() {
        setUI((PopupMenuUI)UIManager.getUI(this));
    }


    
Returns the name of the L&F class that renders this component.
See Also:
JComponent.getUIClassID
UIDefaults.getUI
Returns:
the string "PopupMenuUI"/**
     * Returns the name of the L&amp;F class that renders this component.
     *
     * @return the string "PopupMenuUI"
     * @see JComponent#getUIClassID
     * @see UIDefaults#getUI
     */
    @BeanProperty(bound = false)
    public String getUIClassID() {
        return uiClassID;
    }

    protected void processFocusEvent(FocusEvent evt) {
        super.processFocusEvent(evt);
    }

    
Processes key stroke events such as mnemonics and accelerators.
Params:
evt –  the key event to be processed/**
     * 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);
    }


    
Returns the model object that handles single selections.
See Also:
SingleSelectionModel
Returns:
the selectionModel property/**
     * Returns the model object that handles single selections.
     *
     * @return the <code>selectionModel</code> property
     * @see SingleSelectionModel
     */
    public SingleSelectionModel getSelectionModel() {
        return selectionModel;
    }

    
Sets the model object to handle single selections.
Params:
model – the new SingleSelectionModel
See Also:
SingleSelectionModel/**
     * Sets the model object to handle single selections.
     *
     * @param model the new <code>SingleSelectionModel</code>
     * @see SingleSelectionModel
     */
    @BeanProperty(bound = false, expert = true, description
            = "The selection model for the popup menu")
    public void setSelectionModel(SingleSelectionModel model) {
        selectionModel = model;
    }

    
Appends the specified menu item to the end of this menu.
Params:
menuItem – the JMenuItem to add
Returns:
the JMenuItem added/**
     * Appends the specified menu item to the end of this menu.
     *
     * @param menuItem the <code>JMenuItem</code> to add
     * @return the <code>JMenuItem</code> added
     */
    public JMenuItem add(JMenuItem menuItem) {
        super.add(menuItem);
        return menuItem;
    }

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

    
Appends a new menu item to the end of the menu which
dispatches the specified Action object.
Params:
a – the Action to add to the menu
See Also:
Action
Returns:
the new menu item/**
     * Appends a new menu item to the end of the menu which
     * dispatches the specified <code>Action</code> object.
     *
     * @param a the <code>Action</code> to add to the menu
     * @return the new menu item
     * @see Action
     */
    public JMenuItem add(Action a) {
        JMenuItem mi = createActionComponent(a);
        mi.setAction(a);
        add(mi);
        return mi;
    }

    
Returns an point which has been adjusted to take into account of the
desktop bounds, taskbar and multi-monitor configuration.

This adustment may be cancelled by invoking the application with
-Djavax.swing.adjustPopupLocationToFit=false
/**
     * Returns an point which has been adjusted to take into account of the
     * desktop bounds, taskbar and multi-monitor configuration.
     * <p>
     * This adustment may be cancelled by invoking the application with
     * -Djavax.swing.adjustPopupLocationToFit=false
     */
    Point adjustPopupLocationToFitScreen(int xPosition, int yPosition) {
        Point popupLocation = new Point(xPosition, yPosition);

        if(popupPostionFixDisabled == true || GraphicsEnvironment.isHeadless()) {
            return popupLocation;
        }

        // Get screen bounds
        GraphicsConfiguration gc = getCurrentGraphicsConfiguration(popupLocation);
        if (gc == null) {
            // If we don't have GraphicsConfiguration use primary screen
            gc = GraphicsEnvironment.getLocalGraphicsEnvironment().
                            getDefaultScreenDevice().getDefaultConfiguration();
        }
        Rectangle scrBounds = gc.getBounds();

        // Calculate the screen size that popup should fit
        Dimension popupSize = JPopupMenu.this.getPreferredSize();
        long popupRightX = (long)popupLocation.x + (long)popupSize.width;
        long popupBottomY = (long)popupLocation.y + (long)popupSize.height;
        int scrWidth = scrBounds.width;
        int scrHeight = scrBounds.height;

        if (!canPopupOverlapTaskBar()) {
            // Insets include the task bar. Take them into account.
            Toolkit toolkit = Toolkit.getDefaultToolkit();
            Insets scrInsets = toolkit.getScreenInsets(gc);
            scrBounds.x += scrInsets.left;
            scrBounds.y += scrInsets.top;
            scrWidth -= scrInsets.left + scrInsets.right;
            scrHeight -= scrInsets.top + scrInsets.bottom;
        }
        int scrRightX = scrBounds.x + scrWidth;
        int scrBottomY = scrBounds.y + scrHeight;

        // Ensure that popup menu fits the screen
        if (popupRightX > (long) scrRightX) {
            popupLocation.x = scrRightX - popupSize.width;
        }

        if (popupBottomY > (long) scrBottomY) {
            popupLocation.y = scrBottomY - popupSize.height;
        }

        if (popupLocation.x < scrBounds.x) {
            popupLocation.x = scrBounds.x;
        }

        if (popupLocation.y < scrBounds.y) {
            popupLocation.y = scrBounds.y;
        }

        return popupLocation;
    }

    
Tries to find GraphicsConfiguration
that contains the mouse cursor position.
Can return null.
/**
     * Tries to find GraphicsConfiguration
     * that contains the mouse cursor position.
     * Can return null.
     */
    private GraphicsConfiguration getCurrentGraphicsConfiguration(
            Point popupLocation) {
        GraphicsConfiguration gc = null;
        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(popupLocation)) {
                    gc = dgc;
                    break;
                }
            }
        }
        // If not found and we have invoker, ask invoker about his gc
        if(gc == null && getInvoker() != null) {
            gc = getInvoker().getGraphicsConfiguration();
        }
        return gc;
    }

    
Returns whether popup is allowed to be shown above the task bar.
/**
     * Returns whether popup is allowed to be shown above the task bar.
     */
    static boolean canPopupOverlapTaskBar() {
        boolean result = true;

        Toolkit tk = Toolkit.getDefaultToolkit();
        if (tk instanceof SunToolkit) {
            result = ((SunToolkit)tk).canPopupOverlapTaskBar();
        }

        return result;
    }

    
Factory method which creates the JMenuItem for
Actions added to the JPopupMenu.
Params:
a – the Action for the menu item to be added
See Also:
Action
Returns:
the new menu item
Since:
1.3/**
     * Factory method which creates the <code>JMenuItem</code> for
     * <code>Actions</code> added to the <code>JPopupMenu</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 PropertyChangeListener
which updates the control as changes to the Action occur.
Params:
b – the menu item for which to create a listener
Returns:
a properly configured PropertyChangeListener/**
     * Returns a properly configured <code>PropertyChangeListener</code>
     * which updates the control as changes to the <code>Action</code> occur.
     *
     * @param b the menu item for which to create a listener
     * @return a properly configured {@code PropertyChangeListener}
     */
    protected PropertyChangeListener createActionChangeListener(JMenuItem b) {
        return b.createActionPropertyChangeListener0(b.getAction());
    }

    
Removes the component at the specified index from this popup menu.
Params:
pos – the position of the item to be removed
Throws:
IllegalArgumentException – if the value of
                         pos < 0, or if the value of
                         pos is greater than the
                         number of items/**
     * Removes the component at the specified index from this popup menu.
     *
     * @param       pos the position of the item to be removed
     * @exception   IllegalArgumentException if the value of
     *                          <code>pos</code> &lt; 0, or if the value of
     *                          <code>pos</code> is greater than the
     *                          number of items
     */
    public void remove(int pos) {
        if (pos < 0) {
            throw new IllegalArgumentException("index less than zero.");
        }
        if (pos > getComponentCount() -1) {
            throw new IllegalArgumentException("index greater than the number of items.");
        }
        super.remove(pos);
    }

    
Sets the value of the lightWeightPopupEnabled property,
which by default is true.
By default, when a look and feel displays a popup,
it can choose to
use a lightweight (all-Java) popup.
Lightweight popup windows are more efficient than heavyweight
(native peer) windows,
but lightweight and heavyweight components do not mix well in a GUI.
If your application mixes lightweight and heavyweight components,
you should disable lightweight popups.
Some look and feels might always use heavyweight popups,
no matter what the value of this property.
Params:
aFlag –  false to disable lightweight popups
See Also:
isLightWeightPopupEnabled/**
     * Sets the value of the <code>lightWeightPopupEnabled</code> property,
     * which by default is <code>true</code>.
     * By default, when a look and feel displays a popup,
     * it can choose to
     * use a lightweight (all-Java) popup.
     * Lightweight popup windows are more efficient than heavyweight
     * (native peer) windows,
     * but lightweight and heavyweight components do not mix well in a GUI.
     * If your application mixes lightweight and heavyweight components,
     * you should disable lightweight popups.
     * Some look and feels might always use heavyweight popups,
     * no matter what the value of this property.
     *
     * @param aFlag  <code>false</code> to disable lightweight popups
     *
     * @see #isLightWeightPopupEnabled
     */
    @BeanProperty(bound = false, expert = true, description
            = "Determines whether lightweight popups are used when possible")
    public void setLightWeightPopupEnabled(boolean aFlag) {
        // NOTE: this use to set the flag on a shared JPopupMenu, which meant
        // this effected ALL JPopupMenus.
        lightWeightPopup = aFlag;
    }

    
Gets the lightWeightPopupEnabled property.
See Also:
setLightWeightPopupEnabled
Returns:
the value of the lightWeightPopupEnabled property/**
     * Gets the <code>lightWeightPopupEnabled</code> property.
     *
     * @return the value of the <code>lightWeightPopupEnabled</code> property
     * @see #setLightWeightPopupEnabled
     */
    public boolean isLightWeightPopupEnabled() {
        return lightWeightPopup;
    }

    
Returns the popup menu's label
See Also:
setLabel
Returns:
a string containing the popup menu's label/**
     * Returns the popup menu's label
     *
     * @return a string containing the popup menu's label
     * @see #setLabel
     */
    public String getLabel() {
        return label;
    }

    
Sets the popup menu's label.  Different look and feels may choose
to display or not display this.
Params:
label – a string specifying the label for the popup menu
See Also:
setLabel/**
     * Sets the popup menu's label.  Different look and feels may choose
     * to display or not display this.
     *
     * @param label a string specifying the label for the popup menu
     *
     * @see #setLabel
     */
    @BeanProperty(description
            = "The label for the popup menu.")
    public void setLabel(String label) {
        String oldValue = this.label;
        this.label = label;
        firePropertyChange("label", oldValue, label);
        if (accessibleContext != null) {
            accessibleContext.firePropertyChange(
                AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
                oldValue, label);
        }
        invalidate();
        repaint();
    }

    
Appends a new separator at the end of the menu.
/**
     * Appends a new separator at the end of the menu.
     */
    public void addSeparator() {
        add( new JPopupMenu.Separator() );
    }

    
Inserts a menu item for the specified Action object at
a given position.
Params:
a –  the Action object to insert
index –      specifies the position at which to insert the
                  Action, where 0 is the first
Throws:
IllegalArgumentException – if index < 0
See Also:
Action/**
     * Inserts a menu item for the specified <code>Action</code> object at
     * a given position.
     *
     * @param a  the <code>Action</code> object to insert
     * @param index      specifies the position at which to insert the
     *                   <code>Action</code>, where 0 is the first
     * @exception IllegalArgumentException if <code>index</code> &lt; 0
     * @see Action
     */
    public void insert(Action a, int index) {
        JMenuItem mi = createActionComponent(a);
        mi.setAction(a);
        insert(mi, index);
    }

    
Inserts the specified component into the menu at a given
position.
Params:
component –  the Component to insert
index –      specifies the position at which
                  to insert the component, where 0 is the first
Throws:
IllegalArgumentException – if index < 0/**
     * Inserts the specified component into the menu at a given
     * position.
     *
     * @param component  the <code>Component</code> to insert
     * @param index      specifies the position at which
     *                   to insert the component, where 0 is the first
     * @exception IllegalArgumentException if <code>index</code> &lt; 0
     */
    public void insert(Component component, int index) {
        if (index < 0) {
            throw new IllegalArgumentException("index less than zero.");
        }

        int nitems = getComponentCount();
        // PENDING(ges): Why not use an array?
        Vector<Component> tempItems = new Vector<Component>();

        /* Remove the item at index, nitems-index times
           storing them in a temporary vector in the
           order they appear on the menu.
           */
        for (int i = index ; i < nitems; i++) {
            tempItems.addElement(getComponent(index));
            remove(index);
        }

        add(component);

        /* Add the removed items back to the menu, they are
           already in the correct order in the temp vector.
           */
        for (Component tempItem : tempItems) {
            add(tempItem);
        }
    }

    
 Adds a PopupMenu listener.
 @param l  the PopupMenuListener to add
/**
     *  Adds a <code>PopupMenu</code> listener.
     *
     *  @param l  the <code>PopupMenuListener</code> to add
     */
    public void addPopupMenuListener(PopupMenuListener l) {
        listenerList.add(PopupMenuListener.class,l);
    }

    
Removes a PopupMenu listener.
Params:
l –  the PopupMenuListener to remove/**
     * Removes a <code>PopupMenu</code> listener.
     *
     * @param l  the <code>PopupMenuListener</code> to remove
     */
    public void removePopupMenuListener(PopupMenuListener l) {
        listenerList.remove(PopupMenuListener.class,l);
    }

    
Returns an array of all the PopupMenuListeners added
to this JMenuItem with addPopupMenuListener().
Returns:
all of the PopupMenuListeners added or an empty
        array if no listeners have been added
Since:
1.4/**
     * Returns an array of all the <code>PopupMenuListener</code>s added
     * to this JMenuItem with addPopupMenuListener().
     *
     * @return all of the <code>PopupMenuListener</code>s added or an empty
     *         array if no listeners have been added
     * @since 1.4
     */
    @BeanProperty(bound = false)
    public PopupMenuListener[] getPopupMenuListeners() {
        return listenerList.getListeners(PopupMenuListener.class);
    }

    
Adds a MenuKeyListener to the popup menu.
Params:
l – the MenuKeyListener to be added
Since:
1.5/**
     * Adds a <code>MenuKeyListener</code> to the popup menu.
     *
     * @param l the <code>MenuKeyListener</code> to be added
     * @since 1.5
     */
    public void addMenuKeyListener(MenuKeyListener l) {
        listenerList.add(MenuKeyListener.class, l);
    }

    
Removes a MenuKeyListener from the popup menu.
Params:
l – the MenuKeyListener to be removed
Since:
1.5/**
     * Removes a <code>MenuKeyListener</code> from the popup menu.
     *
     * @param l the <code>MenuKeyListener</code> to be removed
     * @since 1.5
     */
    public void removeMenuKeyListener(MenuKeyListener l) {
        listenerList.remove(MenuKeyListener.class, l);
    }

    
Returns an array of all the MenuKeyListeners added
to this JPopupMenu with addMenuKeyListener().
Returns:
all of the MenuKeyListeners added or an empty
        array if no listeners have been added
Since:
1.5/**
     * Returns an array of all the <code>MenuKeyListener</code>s added
     * to this JPopupMenu with addMenuKeyListener().
     *
     * @return all of the <code>MenuKeyListener</code>s added or an empty
     *         array if no listeners have been added
     * @since 1.5
     */
    @BeanProperty(bound = false)
    public MenuKeyListener[] getMenuKeyListeners() {
        return listenerList.getListeners(MenuKeyListener.class);
    }

    
Notifies PopupMenuListeners that this popup menu will
become visible.
/**
     * Notifies <code>PopupMenuListener</code>s that this popup menu will
     * become visible.
     */
    protected void firePopupMenuWillBecomeVisible() {
        Object[] listeners = listenerList.getListenerList();
        PopupMenuEvent e=null;
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==PopupMenuListener.class) {
                if (e == null)
                    e = new PopupMenuEvent(this);
                ((PopupMenuListener)listeners[i+1]).popupMenuWillBecomeVisible(e);
            }
        }
    }

    
Notifies PopupMenuListeners that this popup menu will
become invisible.
/**
     * Notifies <code>PopupMenuListener</code>s that this popup menu will
     * become invisible.
     */
    protected void firePopupMenuWillBecomeInvisible() {
        Object[] listeners = listenerList.getListenerList();
        PopupMenuEvent e=null;
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==PopupMenuListener.class) {
                if (e == null)
                    e = new PopupMenuEvent(this);
                ((PopupMenuListener)listeners[i+1]).popupMenuWillBecomeInvisible(e);
            }
        }
    }

    
Notifies PopupMenuListeners that this popup menu is
cancelled.
/**
     * Notifies <code>PopupMenuListeners</code> that this popup menu is
     * cancelled.
     */
    protected void firePopupMenuCanceled() {
        Object[] listeners = listenerList.getListenerList();
        PopupMenuEvent e=null;
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==PopupMenuListener.class) {
                if (e == null)
                    e = new PopupMenuEvent(this);
                ((PopupMenuListener)listeners[i+1]).popupMenuCanceled(e);
            }
        }
    }

    
Always returns true since popups, by definition, should always
be on top of all other windows.
Returns:
true/**
     * Always returns true since popups, by definition, should always
     * be on top of all other windows.
     * @return true
     */
    // package private
    boolean alwaysOnTop() {
        return true;
    }

    
Lays out the container so that it uses the minimum space
needed to display its contents.
/**
     * Lays out the container so that it uses the minimum space
     * needed to display its contents.
     */
    public void pack() {
        if(popup != null) {
            Dimension pref = getPreferredSize();

            if (pref == null || pref.width != getWidth() ||
                                pref.height != getHeight()) {
                showPopup();
            } else {
                validate();
            }
        }
    }

    
Sets the visibility of the popup menu.
Params:
b – true to make the popup visible, or false to
         hide it/**
     * Sets the visibility of the popup menu.
     *
     * @param b true to make the popup visible, or false to
     *          hide it
     */
    @BeanProperty(description
            = "Makes the popup visible")
    public void setVisible(boolean b) {
        if (DEBUG) {
            System.out.println("JPopupMenu.setVisible " + b);
        }

        // Is it a no-op?
        if (b == isVisible())
            return;

        // if closing, first close all Submenus
        if (b == false) {

            // 4234793: This is a workaround because JPopupMenu.firePopupMenuCanceled is
            // a protected method and cannot be called from BasicPopupMenuUI directly
            // The real solution could be to make
            // firePopupMenuCanceled public and call it directly.
            Boolean doCanceled = (Boolean)getClientProperty("JPopupMenu.firePopupMenuCanceled");
            if (doCanceled != null && doCanceled == Boolean.TRUE) {
                putClientProperty("JPopupMenu.firePopupMenuCanceled", Boolean.FALSE);
                firePopupMenuCanceled();
            }
            getSelectionModel().clearSelection();

        } else {
            // This is a popup menu with MenuElement children,
            // set selection path before popping up!
            if (isPopupMenu()) {
                MenuElement me[] = new MenuElement[1];
                me[0] = this;
                MenuSelectionManager.defaultManager().setSelectedPath(me);
            }
        }

        if(b) {
            firePopupMenuWillBecomeVisible();
            showPopup();
            firePropertyChange("visible", Boolean.FALSE, Boolean.TRUE);


        } else if(popup != null) {
            firePopupMenuWillBecomeInvisible();
            popup.hide();
            popup = null;
            firePropertyChange("visible", Boolean.TRUE, Boolean.FALSE);
            // 4694797: When popup menu is made invisible, selected path
            // should be cleared
            if (isPopupMenu()) {
                MenuSelectionManager.defaultManager().clearSelectedPath();
            }
        }
    }

    
Retrieves Popup instance from the
PopupMenuUI that has had show invoked on
it. If the current popup is non-null,
this will invoke dispose of it, and then
show the new one.

This does NOT fire any events, it is up the caller to dispatch
the necessary events.
/**
     * Retrieves <code>Popup</code> instance from the
     * <code>PopupMenuUI</code> that has had <code>show</code> invoked on
     * it. If the current <code>popup</code> is non-null,
     * this will invoke <code>dispose</code> of it, and then
     * <code>show</code> the new one.
     * <p>
     * This does NOT fire any events, it is up the caller to dispatch
     * the necessary events.
     */
    private void showPopup() {
        Popup oldPopup = popup;

        if (oldPopup != null) {
            oldPopup.hide();
        }
        PopupFactory popupFactory = PopupFactory.getSharedInstance();

        if (isLightWeightPopupEnabled()) {
            popupFactory.setPopupType(PopupFactory.LIGHT_WEIGHT_POPUP);
        }
        else {
            popupFactory.setPopupType(PopupFactory.HEAVY_WEIGHT_POPUP);
        }

        // adjust the location of the popup
        Point p = adjustPopupLocationToFitScreen(desiredLocationX,desiredLocationY);
        desiredLocationX = p.x;
        desiredLocationY = p.y;

        Popup newPopup = getUI().getPopup(this, desiredLocationX,
                                          desiredLocationY);

        popupFactory.setPopupType(PopupFactory.LIGHT_WEIGHT_POPUP);
        popup = newPopup;
        newPopup.show();
    }

    
Returns true if the popup menu is visible (currently
being displayed).
/**
     * Returns true if the popup menu is visible (currently
     * being displayed).
     */
    public boolean isVisible() {
        return popup != null;
    }

    
Sets the location of the upper left corner of the
popup menu using x, y coordinates.
 The method changes the geometry-related data. Therefore, the native windowing system may ignore such requests, or it may modify the requested data, so that the JPopupMenu object is placed and sized in a way that corresponds closely to the desktop settings. 
Params:
x – the x coordinate of the popup's new position
         in the screen's coordinate space
y – the y coordinate of the popup's new position
         in the screen's coordinate space/**
     * Sets the location of the upper left corner of the
     * popup menu using x, y coordinates.
     * <p>
     * The method changes the geometry-related data. Therefore,
     * the native windowing system may ignore such requests, or it may modify
     * the requested data, so that the {@code JPopupMenu} object is placed and sized
     * in a way that corresponds closely to the desktop settings.
     *
     * @param x the x coordinate of the popup's new position
     *          in the screen's coordinate space
     * @param y the y coordinate of the popup's new position
     *          in the screen's coordinate space
     */
    @BeanProperty(description
            = "The location of the popup menu.")
    public void setLocation(int x, int y) {
        int oldX = desiredLocationX;
        int oldY = desiredLocationY;

        desiredLocationX = x;
        desiredLocationY = y;
        if(popup != null && (x != oldX || y != oldY)) {
            showPopup();
        }
    }

    
Returns true if the popup menu is a standalone popup menu
rather than the submenu of a JMenu.
Returns:
true if this menu is a standalone popup menu, otherwise false/**
     * Returns true if the popup menu is a standalone popup menu
     * rather than the submenu of a <code>JMenu</code>.
     *
     * @return true if this menu is a standalone popup menu, otherwise false
     */
    private boolean isPopupMenu() {
        return  ((invoker != null) && !(invoker instanceof JMenu));
    }

    
Returns the component which is the 'invoker' of this
popup menu.
Returns:
the Component in which the popup menu is displayed/**
     * Returns the component which is the 'invoker' of this
     * popup menu.
     *
     * @return the <code>Component</code> in which the popup menu is displayed
     */
    public Component getInvoker() {
        return this.invoker;
    }

    
Sets the invoker of this popup menu -- the component in which
the popup menu menu is to be displayed.
Params:
invoker – the Component in which the popup
         menu is displayed/**
     * Sets the invoker of this popup menu -- the component in which
     * the popup menu menu is to be displayed.
     *
     * @param invoker the <code>Component</code> in which the popup
     *          menu is displayed
     */
    @BeanProperty(bound = false, expert = true, description
            = "The invoking component for the popup menu")
    public void setInvoker(Component invoker) {
        Component oldInvoker = this.invoker;
        this.invoker = invoker;
        if ((oldInvoker != this.invoker) && (ui != null)) {
            ui.uninstallUI(this);
            ui.installUI(this);
        }
        invalidate();
    }

    
Displays the popup menu at the position x,y in the coordinate
space of the component invoker.
Params:
invoker – the component in whose space the popup menu is to appear
x – the x coordinate in invoker's coordinate space at which
the popup menu is to be displayed
y – the y coordinate in invoker's coordinate space at which
the popup menu is to be displayed/**
     * Displays the popup menu at the position x,y in the coordinate
     * space of the component invoker.
     *
     * @param invoker the component in whose space the popup menu is to appear
     * @param x the x coordinate in invoker's coordinate space at which
     * the popup menu is to be displayed
     * @param y the y coordinate in invoker's coordinate space at which
     * the popup menu is to be displayed
     */
    public void show(Component invoker, int x, int y) {
        if (DEBUG) {
            System.out.println("in JPopupMenu.show " );
        }
        setInvoker(invoker);
        Frame newFrame = getFrame(invoker);
        if (newFrame != frame) {
            // Use the invoker's frame so that events
            // are propagated properly
            if (newFrame!=null) {
                this.frame = newFrame;
                if(popup != null) {
                    setVisible(false);
                }
            }
        }
        Point invokerOrigin;
        if (invoker != null) {
            invokerOrigin = invoker.getLocationOnScreen();

            // To avoid integer overflow
            long lx, ly;
            lx = ((long) invokerOrigin.x) +
                 ((long) x);
            ly = ((long) invokerOrigin.y) +
                 ((long) y);
            if(lx > Integer.MAX_VALUE) lx = Integer.MAX_VALUE;
            if(lx < Integer.MIN_VALUE) lx = Integer.MIN_VALUE;
            if(ly > Integer.MAX_VALUE) ly = Integer.MAX_VALUE;
            if(ly < Integer.MIN_VALUE) ly = Integer.MIN_VALUE;

            setLocation((int) lx, (int) ly);
        } else {
            setLocation(x, y);
        }
        setVisible(true);
    }

    
Returns the popup menu which is at the root of the menu system
for this popup menu.
Returns:
the topmost grandparent JPopupMenu/**
     * Returns the popup menu which is at the root of the menu system
     * for this popup menu.
     *
     * @return the topmost grandparent <code>JPopupMenu</code>
     */
    JPopupMenu getRootPopupMenu() {
        JPopupMenu mp = this;
        while((mp!=null) && (mp.isPopupMenu()!=true) &&
              (mp.getInvoker() != null) &&
              (mp.getInvoker().getParent() != null) &&
              (mp.getInvoker().getParent() instanceof JPopupMenu)
              ) {
            mp = (JPopupMenu) mp.getInvoker().getParent();
        }
        return mp;
    }

    
Returns the component at the specified index.
Params:
i –  the index of the component, where 0 is the first
Returns:
the Component at that index
Deprecated:
replaced by Container.getComponent(int)/**
     * Returns the component at the specified index.
     *
     * @param i  the index of the component, where 0 is the first
     * @return the <code>Component</code> at that index
     * @deprecated replaced by {@link java.awt.Container#getComponent(int)}
     */
    @Deprecated
    public Component getComponentAtIndex(int i) {
        return getComponent(i);
    }

    
Returns the index of the specified component.
Params:
c – the Component to find
Returns:
the index of the component, where 0 is the first;
        or -1 if the component is not found/**
     * Returns the index of the specified component.
     *
     * @param  c the <code>Component</code> to find
     * @return the index of the component, where 0 is the first;
     *         or -1 if the component is not found
     */
    public int getComponentIndex(Component c) {
        int ncomponents = this.getComponentCount();
        Component[] component = this.getComponents();
        for (int i = 0 ; i < ncomponents ; i++) {
            Component comp = component[i];
            if (comp == c)
                return i;
        }
        return -1;
    }

    
Sets the size of the Popup window using a Dimension object.
This is equivalent to setPreferredSize(d).
Params:
d –   the Dimension specifying the new size
of this component./**
     * Sets the size of the Popup window using a <code>Dimension</code> object.
     * This is equivalent to <code>setPreferredSize(d)</code>.
     *
     * @param d   the <code>Dimension</code> specifying the new size
     * of this component.
     */
    @BeanProperty(description
            = "The size of the popup menu")
    public void setPopupSize(Dimension d) {
        Dimension oldSize = getPreferredSize();

        setPreferredSize(d);
        if (popup != null) {
            Dimension newSize = getPreferredSize();

            if (!oldSize.equals(newSize)) {
                showPopup();
            }
        }
    }

    
Sets the size of the Popup window to the specified width and
height. This is equivalent to
 setPreferredSize(new Dimension(width, height)).
Params:
width – the new width of the Popup in pixels
height – the new height of the Popup in pixels/**
     * Sets the size of the Popup window to the specified width and
     * height. This is equivalent to
     *  <code>setPreferredSize(new Dimension(width, height))</code>.
     *
     * @param width the new width of the Popup in pixels
     * @param height the new height of the Popup in pixels
     */
    @BeanProperty(description
            = "The size of the popup menu")
    public void setPopupSize(int width, int height) {
        setPopupSize(new Dimension(width, height));
    }

    
Sets the currently selected component,  This will result
in a change to the selection model.
Params:
sel – the Component to select/**
     * Sets the currently selected component,  This will result
     * in a change to the selection model.
     *
     * @param sel the <code>Component</code> to select
     */
    @BeanProperty(expert = true, hidden = true, description
            = "The selected component on the popup menu")
    public void setSelected(Component sel) {
        SingleSelectionModel model = getSelectionModel();
        int index = getComponentIndex(sel);
        model.setSelectedIndex(index);
    }

    
Checks whether the border should be painted.
See Also:
setBorderPainted
Returns:
true if the border is painted, false otherwise/**
     * Checks whether the border should be painted.
     *
     * @return true if the border is painted, false otherwise
     * @see #setBorderPainted
     */
    public boolean isBorderPainted() {
        return paintBorder;
    }

    
Sets whether the border should be painted.
Params:
b – if true, the border is painted.
See Also:
isBorderPainted/**
     * Sets whether the border should be painted.
     *
     * @param b if true, the border is painted.
     * @see #isBorderPainted
     */
    @BeanProperty(bound = false, description
            = "Is the border of the popup menu painted")
    public void setBorderPainted(boolean b) {
        paintBorder = b;
        repaint();
    }

    
Paints the popup menu's border if the borderPainted
property is true.
Params:
g –  the Graphics object
See Also:
JComponent.paint
JComponent.setBorder/**
     * Paints the popup menu's border if the <code>borderPainted</code>
     * property is <code>true</code>.
     * @param g  the <code>Graphics</code> object
     *
     * @see JComponent#paint
     * @see JComponent#setBorder
     */
    protected void paintBorder(Graphics g) {
        if (isBorderPainted()) {
            super.paintBorder(g);
        }
    }

    
Returns the margin, in pixels, between the popup menu's border and
its containers.
Returns:
an Insets object containing the margin values./**
     * Returns the margin, in pixels, between the popup menu's border and
     * its containers.
     *
     * @return an <code>Insets</code> object containing the margin values.
     */
    @BeanProperty(bound = false)
    public Insets getMargin() {
        if(margin == null) {
            return new Insets(0,0,0,0);
        } else {
            return margin;
        }
    }


    
Examines the list of menu items to determine whether
popup is a popup menu.
Params:
popup –  a JPopupMenu
Returns:
true if popup/**
     * Examines the list of menu items to determine whether
     * <code>popup</code> is a popup menu.
     *
     * @param popup  a <code>JPopupMenu</code>
     * @return true if <code>popup</code>
     */
    boolean isSubPopupMenu(JPopupMenu popup) {
        int ncomponents = this.getComponentCount();
        Component[] component = this.getComponents();
        for (int i = 0 ; i < ncomponents ; i++) {
            Component comp = component[i];
            if (comp instanceof JMenu) {
                JMenu menu = (JMenu)comp;
                JPopupMenu subPopup = menu.getPopupMenu();
                if (subPopup == popup)
                    return true;
                if (subPopup.isSubPopupMenu(popup))
                    return true;
            }
        }
        return false;
    }


    private static Frame getFrame(Component c) {
        Component w = c;

        while(!(w instanceof Frame) && (w!=null)) {
            w = w.getParent();
        }
        return (Frame)w;
    }


    
Returns a string representation of this JPopupMenu.
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 null.
Returns:
 a string representation of this JPopupMenu./**
     * Returns a string representation of this <code>JPopupMenu</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 <code>JPopupMenu</code>.
     */
    protected String paramString() {
        String labelString = (label != null ?
                              label : "");
        String paintBorderString = (paintBorder ?
                                    "true" : "false");
        String marginString = (margin != null ?
                              margin.toString() : "");
        String lightWeightPopupEnabledString = (isLightWeightPopupEnabled() ?
                                                "true" : "false");
        return super.paramString() +
            ",desiredLocationX=" + desiredLocationX +
            ",desiredLocationY=" + desiredLocationY +
        ",label=" + labelString +
        ",lightWeightPopupEnabled=" + lightWeightPopupEnabledString +
        ",margin=" + marginString +
        ",paintBorder=" + paintBorderString;
    }

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

    
Gets the AccessibleContext associated with this JPopupMenu.
For JPopupMenus, the AccessibleContext takes the form of an
AccessibleJPopupMenu.
A new AccessibleJPopupMenu instance is created if necessary.
Returns:
an AccessibleJPopupMenu that serves as the
        AccessibleContext of this JPopupMenu/**
     * Gets the AccessibleContext associated with this JPopupMenu.
     * For JPopupMenus, the AccessibleContext takes the form of an
     * AccessibleJPopupMenu.
     * A new AccessibleJPopupMenu instance is created if necessary.
     *
     * @return an AccessibleJPopupMenu that serves as the
     *         AccessibleContext of this JPopupMenu
     */
    @BeanProperty(bound = false)
    public AccessibleContext getAccessibleContext() {
        if (accessibleContext == null) {
            accessibleContext = new AccessibleJPopupMenu();
        }
        return accessibleContext;
    }

    
This class implements accessibility support for the
JPopupMenu class.  It provides an implementation of the
Java Accessibility API appropriate to popup menu user-interface
elements.
/**
     * This class implements accessibility support for the
     * <code>JPopupMenu</code> class.  It provides an implementation of the
     * Java Accessibility API appropriate to popup menu user-interface
     * elements.
     */
    @SuppressWarnings("serial")
    protected class AccessibleJPopupMenu extends AccessibleJComponent
        implements PropertyChangeListener {

        
AccessibleJPopupMenu constructor
Since:
1.5/**
         * AccessibleJPopupMenu constructor
         *
         * @since 1.5
         */
        protected AccessibleJPopupMenu() {
            JPopupMenu.this.addPropertyChangeListener(this);
        }

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

        
This method gets called when a bound property is changed.
Params:
e – A PropertyChangeEvent object describing
the event source and the property that has changed. Must not be null.
Throws:
NullPointerException – if the parameter is null.
Since:
1.5/**
         * This method gets called when a bound property is changed.
         * @param e A <code>PropertyChangeEvent</code> object describing
         * the event source and the property that has changed. Must not be null.
         *
         * @throws NullPointerException if the parameter is null.
         * @since 1.5
         */
        public void propertyChange(PropertyChangeEvent e) {
            String propertyName = e.getPropertyName();
            if (propertyName == "visible") {
                if (e.getOldValue() == Boolean.FALSE &&
                    e.getNewValue() == Boolean.TRUE) {
                    handlePopupIsVisibleEvent(true);

                } else if (e.getOldValue() == Boolean.TRUE &&
                           e.getNewValue() == Boolean.FALSE) {
                    handlePopupIsVisibleEvent(false);
                }
            }
        }

        /*
         * Handles popup "visible" PropertyChangeEvent
         */
        private void handlePopupIsVisibleEvent(boolean visible) {
            if (visible) {
                // notify listeners that the popup became visible
                firePropertyChange(ACCESSIBLE_STATE_PROPERTY,
                                   null, AccessibleState.VISIBLE);
                // notify listeners that a popup list item is selected
                fireActiveDescendant();
            } else {
                // notify listeners that the popup became hidden
                firePropertyChange(ACCESSIBLE_STATE_PROPERTY,
                                   AccessibleState.VISIBLE, null);
            }
        }

        /*
         * Fires AccessibleActiveDescendant PropertyChangeEvent to notify listeners
         * on the popup menu invoker that a popup list item has been selected
         */
        private void fireActiveDescendant() {
            if (JPopupMenu.this instanceof BasicComboPopup) {
                // get the popup list
                JList<?> popupList = ((BasicComboPopup)JPopupMenu.this).getList();
                if (popupList == null) {
                    return;
                }

                // get the first selected item
                AccessibleContext ac = popupList.getAccessibleContext();
                AccessibleSelection selection = ac.getAccessibleSelection();
                if (selection == null) {
                    return;
                }
                Accessible a = selection.getAccessibleSelection(0);
                if (a == null) {
                    return;
                }
                AccessibleContext selectedItem = a.getAccessibleContext();

                // fire the event with the popup invoker as the source.
                if (selectedItem != null && invoker != null) {
                    AccessibleContext invokerContext = invoker.getAccessibleContext();
                    if (invokerContext != null) {
                        // Check invokerContext because Component.getAccessibleContext
                        // returns null. Classes that extend Component are responsible
                        // for returning a non-null AccessibleContext.
                        invokerContext.firePropertyChange(
                            ACCESSIBLE_ACTIVE_DESCENDANT_PROPERTY,
                            null, selectedItem);
                    }
                }
            }
        }
    } // inner class AccessibleJPopupMenu


////////////
// Serialization support.
////////////
    private void writeObject(ObjectOutputStream s) throws IOException {
        Vector<Object> values = new Vector<Object>();

        s.defaultWriteObject();
        // Save the invoker, if its Serializable.
        if(invoker != null && invoker instanceof Serializable) {
            values.addElement("invoker");
            values.addElement(invoker);
        }
        // Save the popup, if its Serializable.
        if(popup != null && popup instanceof Serializable) {
            values.addElement("popup");
            values.addElement(popup);
        }
        s.writeObject(values);

        if (getUIClassID().equals(uiClassID)) {
            byte count = JComponent.getWriteObjCounter(this);
            JComponent.setWriteObjCounter(this, --count);
            if (count == 0 && ui != null) {
                ui.installUI(this);
            }
        }
    }

    // implements javax.swing.MenuElement
    private void readObject(ObjectInputStream s)
        throws IOException, ClassNotFoundException {
        ObjectInputStream.GetField f = s.readFields();

        int newDesiredLocationX = f.get("desiredLocationX", 0);
        int newDesiredLocationY = f.get("desiredLocationY", 0);
        Point p = adjustPopupLocationToFitScreen(
                newDesiredLocationX, newDesiredLocationY);
        desiredLocationX = p.x;
        desiredLocationY = p.y;

        label = (String) f.get("label", null);
        paintBorder = f.get("paintBorder", false);
        margin = (Insets) f.get("margin", null);
        lightWeightPopup = f.get("lightWeightPopup", false);
        selectionModel = (SingleSelectionModel) f.get("selectionModel", null);

        Vector<?>          values = (Vector)s.readObject();
        int             indexCounter = 0;
        int             maxCounter = values.size();

        if(indexCounter < maxCounter && values.elementAt(indexCounter).
           equals("invoker")) {
            invoker = (Component)values.elementAt(++indexCounter);
            indexCounter++;
        }
        if(indexCounter < maxCounter && values.elementAt(indexCounter).
           equals("popup")) {
            popup = (Popup)values.elementAt(++indexCounter);
            indexCounter++;
        }
    }


    
This method is required to conform to the
MenuElement interface, but it not implemented.
See Also:
processMouseEvent.processMouseEvent(MouseEvent, MenuElement[], MenuSelectionManager)/**
     * This method is required to conform to the
     * <code>MenuElement</code> interface, but it not implemented.
     * @see MenuElement#processMouseEvent(MouseEvent, MenuElement[], MenuSelectionManager)
     */
    public void processMouseEvent(MouseEvent event,MenuElement path[],MenuSelectionManager manager) {}

    
Processes a key event forwarded from the
MenuSelectionManager and changes the menu selection,
if necessary, by using MenuSelectionManager's API.

Note: you do not have to forward the event to sub-components.
This is done automatically by the MenuSelectionManager.
Params:
e –  a KeyEvent
path – the MenuElement path array
manager –   the MenuSelectionManager/**
     * Processes a key event forwarded from the
     * <code>MenuSelectionManager</code> and changes the menu selection,
     * if necessary, by using <code>MenuSelectionManager</code>'s API.
     * <p>
     * Note: you do not have to forward the event to sub-components.
     * This is done automatically by the <code>MenuSelectionManager</code>.
     *
     * @param e  a <code>KeyEvent</code>
     * @param path the <code>MenuElement</code> path array
     * @param manager   the <code>MenuSelectionManager</code>
     */
    @SuppressWarnings("deprecation")
    public void processKeyEvent(KeyEvent e, MenuElement path[],
                                MenuSelectionManager manager) {
        MenuKeyEvent mke = new MenuKeyEvent(e.getComponent(), e.getID(),
                                             e.getWhen(), e.getModifiers(),
                                             e.getKeyCode(), e.getKeyChar(),
                                             path, manager);
        processMenuKeyEvent(mke);

        if (mke.isConsumed())  {
            e.consume();
    }
    }

    
Handles a keystroke in a menu.
Params:
e –  a MenuKeyEvent object
Since:
1.5/**
     * Handles a keystroke in a menu.
     *
     * @param e  a <code>MenuKeyEvent</code> object
     * @since 1.5
     */
    private void processMenuKeyEvent(MenuKeyEvent e) {
        switch (e.getID()) {
        case KeyEvent.KEY_PRESSED:
            fireMenuKeyPressed(e); break;
        case KeyEvent.KEY_RELEASED:
            fireMenuKeyReleased(e); break;
        case KeyEvent.KEY_TYPED:
            fireMenuKeyTyped(e); break;
        default:
            break;
        }
    }

    
Notifies all listeners that have registered interest for
notification on this event type.
Params:
event – a MenuKeyEvent
See Also:
EventListenerList/**
     * Notifies all listeners that have registered interest for
     * notification on this event type.
     *
     * @param event a <code>MenuKeyEvent</code>
     * @see EventListenerList
     */
    private void fireMenuKeyPressed(MenuKeyEvent event) {
        Object[] listeners = listenerList.getListenerList();
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==MenuKeyListener.class) {
                ((MenuKeyListener)listeners[i+1]).menuKeyPressed(event);
            }
        }
    }

    
Notifies all listeners that have registered interest for
notification on this event type.
Params:
event – a MenuKeyEvent
See Also:
EventListenerList/**
     * Notifies all listeners that have registered interest for
     * notification on this event type.
     *
     * @param event a <code>MenuKeyEvent</code>
     * @see EventListenerList
     */
    private void fireMenuKeyReleased(MenuKeyEvent event) {
        Object[] listeners = listenerList.getListenerList();
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==MenuKeyListener.class) {
                ((MenuKeyListener)listeners[i+1]).menuKeyReleased(event);
            }
        }
    }

    
Notifies all listeners that have registered interest for
notification on this event type.
Params:
event – a MenuKeyEvent
See Also:
EventListenerList/**
     * Notifies all listeners that have registered interest for
     * notification on this event type.
     *
     * @param event a <code>MenuKeyEvent</code>
     * @see EventListenerList
     */
    private void fireMenuKeyTyped(MenuKeyEvent event) {
        Object[] listeners = listenerList.getListenerList();
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==MenuKeyListener.class) {
                ((MenuKeyListener)listeners[i+1]).menuKeyTyped(event);
            }
        }
    }

    
Messaged when the menubar selection changes to activate or
deactivate this menu. This implements the
javax.swing.MenuElement interface.
Overrides MenuElement.menuSelectionChanged.
Params:
isIncluded –  true if this menu is active, false if
       it is not
See Also:
MenuElement.menuSelectionChanged(boolean)/**
     * Messaged when the menubar selection changes to activate or
     * deactivate this menu. This implements the
     * <code>javax.swing.MenuElement</code> interface.
     * Overrides <code>MenuElement.menuSelectionChanged</code>.
     *
     * @param isIncluded  true if this menu is active, false if
     *        it is not
     * @see MenuElement#menuSelectionChanged(boolean)
     */
    public void menuSelectionChanged(boolean isIncluded) {
        if (DEBUG) {
            System.out.println("In JPopupMenu.menuSelectionChanged " + isIncluded);
        }
        if(invoker instanceof JMenu) {
            JMenu m = (JMenu) invoker;
            if(isIncluded)
                m.setPopupMenuVisible(true);
            else
                m.setPopupMenuVisible(false);
        }
        if (isPopupMenu() && !isIncluded)
          setVisible(false);
    }

    
Returns an array of MenuElements containing the submenu
for this menu component.  It will only return items conforming to
the JMenuElement interface.
If popup menu is null returns
an empty array.  This method is required to conform to the
MenuElement interface.
See Also:
MenuElement.getSubElements
Returns:
an array of MenuElement objects/**
     * Returns an array of <code>MenuElement</code>s containing the submenu
     * for this menu component.  It will only return items conforming to
     * the <code>JMenuElement</code> interface.
     * If popup menu is <code>null</code> returns
     * an empty array.  This method is required to conform to the
     * <code>MenuElement</code> interface.
     *
     * @return an array of <code>MenuElement</code> objects
     * @see MenuElement#getSubElements
     */
    @BeanProperty(bound = false)
    public MenuElement[] getSubElements() {
        MenuElement result[];
        Vector<MenuElement> tmp = new Vector<MenuElement>();
        int c = getComponentCount();
        int i;
        Component m;

        for(i=0 ; i < c ; i++) {
            m = getComponent(i);
            if(m instanceof MenuElement)
                tmp.addElement((MenuElement) m);
        }

        result = new MenuElement[tmp.size()];
        for(i=0,c=tmp.size() ; i < c ; i++)
            result[i] = tmp.elementAt(i);
        return result;
    }

    
Returns this JPopupMenu component.
See Also:
MenuElement.getComponent
Returns:
this JPopupMenu object/**
     * Returns this <code>JPopupMenu</code> component.
     * @return this <code>JPopupMenu</code> object
     * @see MenuElement#getComponent
     */
    public Component getComponent() {
        return this;
    }


    
A popup menu-specific separator.
/**
     * A popup menu-specific separator.
     */
    @SuppressWarnings("serial")
    public static class Separator extends JSeparator
    {
        
Constructs a popup menu-specific Separator.
/**
         * Constructs a popup menu-specific Separator.
         */
        public Separator( )
        {
            super( JSeparator.HORIZONTAL );
        }

        
Returns the name of the L&F class that renders this component.
See Also:
JComponent.getUIClassID
UIDefaults.getUI
Returns:
the string "PopupMenuSeparatorUI"/**
         * Returns the name of the L&amp;F class that renders this component.
         *
         * @return the string "PopupMenuSeparatorUI"
         * @see JComponent#getUIClassID
         * @see UIDefaults#getUI
         */
        public String getUIClassID()
        {
            return "PopupMenuSeparatorUI";

        }
    }

    
Returns true if the MouseEvent is considered a popup trigger
by the JPopupMenu's currently installed UI.
Params:
e – a MouseEvent
Returns:
true if the mouse event is a popup trigger
Since:
1.3/**
     * Returns true if the <code>MouseEvent</code> is considered a popup trigger
     * by the <code>JPopupMenu</code>'s currently installed UI.
     *
     * @param e a {@code MouseEvent}
     * @return true if the mouse event is a popup trigger
     * @since 1.3
     */
    public boolean isPopupTrigger(MouseEvent e) {
        return getUI().isPopupTrigger(e);
    }
}