/*

 * Copyright (c) 1997, 2008, 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.Component;

import java.awt.Dimension;

import java.awt.Graphics;

import java.awt.Insets;

import java.awt.Point;

import java.awt.Rectangle;

import java.awt.event.*;

import java.beans.Transient;

import java.util.Vector;

import java.util.Enumeration;

import java.io.Serializable;

import java.io.ObjectOutputStream;

import java.io.ObjectInputStream;

import java.io.IOException;

import javax.swing.event.*;

import javax.swing.border.Border;

import javax.swing.plaf.*;

import javax.accessibility.*;

/**

 * An implementation of a menu bar. You add <code>JMenu</code> objects to the

 * menu bar to construct a menu. When the user selects a <code>JMenu</code>

 * object, its associated <code>JPopupMenu</code> is displayed, allowing the

 * user to select one of the <code>JMenuItems</code> on it.

 * <p>

 * For information and examples of using menu bars see

 * <a

 href="http://java.sun.com/docs/books/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<sup><font size="-2">TM</font></sup>

 * has been added to the <code>java.beans</code> package.

 * Please see {@link java.beans.XMLEncoder}.

 * @beaninfo

 *   attribute: isContainer true

 * description: A container for holding and displaying menus.

 *

 * @author Georges Saab

 * @author David Karlton

 * @author Arnaud Weber

 * @see JMenu

 * @see JPopupMenu

 * @see JMenuItem

 */

@SuppressWarnings("serial")

public class JMenuBar extends JComponent implements Accessible,MenuElement

{

    /**

     * @see #getUIClassID

     * @see #readObject

     */

    private static final String uiClassID = "MenuBarUI";

    /*

     * Model for the selected subcontrol.

     */

    private transient SingleSelectionModel selectionModel;

    private boolean paintBorder           = true;

    private Insets     margin             = 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.

    /**

     * Creates a new menu bar.

     */

    public JMenuBar() {

        super();

        setFocusTraversalKeysEnabled(false);

        setSelectionModel(new DefaultSingleSelectionModel());

        updateUI();

    }

    /**

     * Returns the menubar's current UI.

     * @see #setUI

     */

    public MenuBarUI getUI() {

        return (MenuBarUI)ui;

    }

    /**

     * Sets the L&F object that renders this component.

     *

     * @param ui the new MenuBarUI L&F object

     * @see UIDefaults#getUI

     * @beaninfo

     *        bound: true

     *       hidden: true

     *    attribute: visualUpdate true

     *  description: The UI object that implements the Component's LookAndFeel.

     */

    public void setUI(MenuBarUI ui) {

        super.setUI(ui);

    }

    /**

     * Resets the UI property with a value from the current look and feel.

     *

     * @see JComponent#updateUI

     */

    public void updateUI() {

        setUI((MenuBarUI)UIManager.getUI(this));

    }

    /**

     * Returns the name of the L&F class that renders this component.

     *

     * @return the string "MenuBarUI"

     * @see JComponent#getUIClassID

     * @see UIDefaults#getUI

     */

    public String getUIClassID() {

        return uiClassID;

    }

    /**

     * Returns the model object that handles single selections.

     *

     * @return the <code>SingleSelectionModel</code> property

     * @see SingleSelectionModel

     */

    public SingleSelectionModel getSelectionModel() {

        return selectionModel;

    }

    /**

     * Sets the model object to handle single selections.

     *

     * @param model the <code>SingleSelectionModel</code> to use

     * @see SingleSelectionModel

     * @beaninfo

     *       bound: true

     * description: The selection model, recording which child is selected.

     */

    public void setSelectionModel(SingleSelectionModel model) {

        SingleSelectionModel oldValue = selectionModel;

        this.selectionModel = model;

        firePropertyChange("selectionModel", oldValue, selectionModel);

    }

    /**

     * Appends the specified menu to the end of the menu bar.

     *

     * @param c the <code>JMenu</code> component to add

     * @return the menu component

     */

    public JMenu add(JMenu c) {

        super.add(c);

        return c;

    }

    /**

     * Returns the menu at the specified position in the menu bar.

     *

     * @param index  an integer giving the position in the menu bar, where

     *               0 is the first position

     * @return the <code>JMenu</code> at that position, or <code>null</code> if

     *          if there is no <code>JMenu</code> at that position (ie. if

     *          it is a <code>JMenuItem</code>)

     */

    public JMenu getMenu(int index) {

        Component c = getComponentAtIndex(index);

        if (c instanceof JMenu)

            return (JMenu) c;

        return null;

    }

    /**

     * Returns the number of items in the menu bar.

     *

     * @return the number of items in the menu bar

     */

    public int getMenuCount() {

        return getComponentCount();

    }

    /**

     * Sets the help menu that appears when the user selects the

     * "help" option in the menu bar. This method is not yet implemented

     * and will throw an exception.

     *

     * @param menu the JMenu that delivers help to the user

     */

    public void setHelpMenu(JMenu menu) {

        throw new Error("setHelpMenu() not yet implemented.");

    }

    /**

     * Gets the help menu for the menu bar.  This method is not yet

     * implemented and will throw an exception.

     *

     * @return the <code>JMenu</code> that delivers help to the user

     */

    @Transient

    public JMenu getHelpMenu() {

        throw new Error("getHelpMenu() not yet implemented.");

    }

    /**

     * Returns the component at the specified index.

     *

     * @param i an integer specifying the position, where 0 is first

     * @return the <code>Component</code> at the position,

     *          or <code>null</code> for an invalid index

     * @deprecated replaced by <code>getComponent(int i)</code>

     */

    @Deprecated

    public Component getComponentAtIndex(int i) {

        if(i < 0 || i >= getComponentCount()) {

            return null;

        }

        return getComponent(i);

    }

    /**

     * Returns the index of the specified component.

     *

     * @param c  the <code>Component</code> to find

     * @return an integer giving the component's position, where 0 is first;

     *          or -1 if it can't be 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 currently selected component, producing a

     * a change to the selection model.

     *

     * @param sel the <code>Component</code> to select

     */

    public void setSelected(Component sel) {

        SingleSelectionModel model = getSelectionModel();

        int index = getComponentIndex(sel);

        model.setSelectedIndex(index);

    }

    /**

     * Returns true if the menu bar currently has a component selected.

     *

     * @return true if a selection has been made, else false

     */

    public boolean isSelected() {

        return selectionModel.isSelected();

    }

    /**

     * Returns true if the menu bars border should be painted.

     *

     * @return  true if the border should be painted, else false

     */

    public boolean isBorderPainted() {

        return paintBorder;

    }

    /**

     * Sets whether the border should be painted.

     *

     * @param b if true and border property is not <code>null</code>,

     *          the border is painted.

     * @see #isBorderPainted

     * @beaninfo

     *        bound: true

     *    attribute: visualUpdate true

     *  description: Whether the border should be painted.

     */

    public void setBorderPainted(boolean b) {

        boolean oldValue = paintBorder;

        paintBorder = b;

        firePropertyChange("borderPainted", oldValue, paintBorder);

        if (b != oldValue) {

            revalidate();

            repaint();

        }

    }

    /**

     * Paints the menubar's border if <code>BorderPainted</code>

     * property is true.

     *

     * @param g the <code>Graphics</code> context to use for painting

     * @see JComponent#paint

     * @see JComponent#setBorder

     */

    protected void paintBorder(Graphics g) {

        if (isBorderPainted()) {

            super.paintBorder(g);

        }

    }

    /**

     * Sets the margin between the menubar's border and

     * its menus. Setting to <code>null</code> will cause the menubar to

     * use the default margins.

     *

     * @param m an Insets object containing the margin values

     * @see Insets

     * @beaninfo

     *        bound: true

     *    attribute: visualUpdate true

     *  description: The space between the menubar's border and its contents

     */

    public void setMargin(Insets m) {

        Insets old = margin;

        this.margin = m;

        firePropertyChange("margin", old, m);

        if (old == null || !old.equals(m)) {

            revalidate();

            repaint();

        }

    }

    /**

     * Returns the margin between the menubar's border and

     * its menus.  If there is no previous margin, it will create

     * a default margin with zero size.

     *

     * @return an <code>Insets</code> object containing the margin values

     * @see Insets

     */

    public Insets getMargin() {

        if(margin == null) {

            return new Insets(0,0,0,0);

        } else {

            return margin;

        }

    }

    /**

     * Implemented to be a <code>MenuElement</code> -- does nothing.

     *

     * @see #getSubElements

     */

    public void processMouseEvent(MouseEvent event,MenuElement path[],MenuSelectionManager manager) {

    }

    /**

     * Implemented to be a <code>MenuElement</code> -- does nothing.

     *

     * @see #getSubElements

     */

    public void processKeyEvent(KeyEvent e,MenuElement path[],MenuSelectionManager manager) {

    }

    /**

     * Implemented to be a <code>MenuElement</code> -- does nothing.

     *

     * @see #getSubElements

     */

    public void menuSelectionChanged(boolean isIncluded) {

    }

    /**

     * Implemented to be a <code>MenuElement</code> -- returns the

     * menus in this menu bar.

     * This is the reason for implementing the <code>MenuElement</code>

     * interface -- so that the menu bar can be treated the same as

     * other menu elements.

     * @return an array of menu items in the menu bar.

     */

    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;

    }

    /**

     * Implemented to be a <code>MenuElement</code>. Returns this object.

     *

     * @return the current <code>Component</code> (this)

     * @see #getSubElements

     */

    public Component getComponent() {

        return this;

    }

    /**

     * Returns a string representation of this <code>JMenuBar</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>JMenuBar</code>

     */

    protected String paramString() {

        String paintBorderString = (paintBorder ?

                                    "true" : "false");

        String marginString = (margin != null ?

                               margin.toString() : "");

        return super.paramString() +

        ",margin=" + marginString +

        ",paintBorder=" + paintBorderString;

    }

/////////////////

// Accessibility support

////////////////

    /**

     * Gets the AccessibleContext associated with this JMenuBar.

     * For JMenuBars, the AccessibleContext takes the form of an

     * AccessibleJMenuBar.

     * A new AccessibleJMenuBar instance is created if necessary.

     *

     * @return an AccessibleJMenuBar that serves as the

     *         AccessibleContext of this JMenuBar

     */

    public AccessibleContext getAccessibleContext() {

        if (accessibleContext == null) {

            accessibleContext = new AccessibleJMenuBar();

        }

        return accessibleContext;

    }

    /**

     * This class implements accessibility support for the

     * <code>JMenuBar</code> class.  It provides an implementation of the

     * Java Accessibility API appropriate to menu bar 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<sup><font size="-2">TM</font></sup>

     * has been added to the <code>java.beans</code> package.

     * Please see {@link java.beans.XMLEncoder}.

     */

    @SuppressWarnings("serial")

    protected class AccessibleJMenuBar extends AccessibleJComponent

        implements AccessibleSelection {

        /**

         * Get the accessible state set of this object.

         *

         * @return an instance of AccessibleState containing the current state

         *         of the object

         */

        public AccessibleStateSet getAccessibleStateSet() {

            AccessibleStateSet states = super.getAccessibleStateSet();

            return states;

        }

        /**

         * Get the role of this object.