/*

 * Copyright 1997-2006 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.swing;

import java.util.EventListener;

import java.awt.*;

import java.awt.event.*;

import java.awt.image.*;

import java.beans.PropertyChangeEvent;

import java.beans.PropertyChangeListener;

import java.io.Serializable;

import java.io.ObjectOutputStream;

import java.io.ObjectInputStream;

import java.io.IOException;

import javax.swing.plaf.*;

import javax.swing.plaf.basic.*;

import javax.swing.event.*;

import javax.accessibility.*;

/**

 * An implementation of an item in a menu. A menu item is essentially a button

 * sitting in a list. When the user selects the "button", the action

 * associated with the menu item is performed. A <code>JMenuItem</code>

 * contained in a <code>JPopupMenu</code> performs exactly that function.

 * <p>

 * Menu items 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 item has many benefits beyond directly

 * configuring a menu item.  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="http://java.sun.com/docs/books/tutorial/uiswing/misc/action.html">How

 * to Use Actions</a>, a section in <em>The Java Tutorial</em>.

 * <p>

 * For further documentation and for examples, see

 * <a

 href="http://java.sun.com/docs/books/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<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 false

 * description: An item which can be selected in a menu.

 *

 * @author Georges Saab

 * @author David Karlton

 * @see JPopupMenu

 * @see JMenu

 * @see JCheckBoxMenuItem

 * @see JRadioButtonMenuItem

 */

public class JMenuItem extends AbstractButton implements Accessible,MenuElement  {

    /**

     * @see #getUIClassID

     * @see #readObject

     */

    private static final String uiClassID = "MenuItemUI";

    /* 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.

    private boolean isMouseDragged = false;

    /**

     * Creates a <code>JMenuItem</code> with no set text or icon.

     */

    public JMenuItem() {

        this(null, (Icon)null);

    }

    /**

     * Creates a <code>JMenuItem</code> with the specified icon.

     *

     * @param icon the icon of the <code>JMenuItem</code>

     */

    public JMenuItem(Icon icon) {

        this(null, icon);

    }

    /**

     * Creates a <code>JMenuItem</code> with the specified text.

     *

     * @param text the text of the <code>JMenuItem</code>

     */

    public JMenuItem(String text) {

        this(text, (Icon)null);

    }

    /**

     * Creates a menu item whose properties are taken from the

     * specified <code>Action</code>.

     *

     * @param a the action of the <code>JMenuItem</code>

     * @since 1.3

     */

    public JMenuItem(Action a) {

        this();

        setAction(a);

    }

    /**

     * Creates a <code>JMenuItem</code> with the specified text and icon.

     *

     * @param text the text of the <code>JMenuItem</code>

     * @param icon the icon of the <code>JMenuItem</code>

     */

    public JMenuItem(String text, Icon icon) {

        setModel(new DefaultButtonModel());

        init(text, icon);

        initFocusability();

    }

    /**

     * Creates a <code>JMenuItem</code> with the specified text and

     * keyboard mnemonic.

     *

     * @param text the text of the <code>JMenuItem</code>

     * @param mnemonic the keyboard mnemonic for the <code>JMenuItem</code>

     */

    public JMenuItem(String text, int mnemonic) {

        setModel(new DefaultButtonModel());

        init(text, null);

        setMnemonic(mnemonic);

        initFocusability();

    }

    /**

     * {@inheritDoc}

     */

    public void setModel(ButtonModel newModel) {

        super.setModel(newModel);

        if(newModel instanceof DefaultButtonModel) {

            ((DefaultButtonModel)newModel).setMenuItem(true);

        }

    }

    /**

     * Inititalizes the focusability of the the <code>JMenuItem</code>.

     * <code>JMenuItem</code>'s are focusable, but subclasses may

     * want to be, this provides them the opportunity to override this

     * and invoke something else, or nothing at all. Refer to

     * {@link javax.swing.JMenu#initFocusability} for the motivation of

     * this.

     */

    void initFocusability() {

        setFocusable(false);

    }

    /**

     * Initializes the menu item with the specified text and icon.

     *

     * @param text the text of the <code>JMenuItem</code>

     * @param icon the icon of the <code>JMenuItem</code>

     */

    protected void init(String text, Icon icon) {

        if(text != null) {

            setText(text);

        }

        if(icon != null) {

            setIcon(icon);

        }

        // Listen for Focus events

        addFocusListener(new MenuItemFocusListener());

        setUIProperty("borderPainted", Boolean.FALSE);

        setFocusPainted(false);

        setHorizontalTextPosition(JButton.TRAILING);

        setHorizontalAlignment(JButton.LEADING);

        updateUI();

    }

    private static class MenuItemFocusListener implements FocusListener,

        Serializable {

        public void focusGained(FocusEvent event) {}

        public void focusLost(FocusEvent event) {

            // When focus is lost, repaint if

            // the focus information is painted

            JMenuItem mi = (JMenuItem)event.getSource();

            if(mi.isFocusPainted()) {

                mi.repaint();

            }

        }

    }

    /**

     * Sets the look and feel object that renders this component.

     *

     * @param ui  the <code>JMenuItemUI</code> 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(MenuItemUI ui) {

        super.setUI(ui);

    }

    /**

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

     *

     * @see JComponent#updateUI

     */

    public void updateUI() {

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

    }

    /**

     * Returns the suffix used to construct the name of the L&F class used to

     * render this component.

     *

     * @return the string "MenuItemUI"

     * @see JComponent#getUIClassID

     * @see UIDefaults#getUI

     */

    public String getUIClassID() {

        return uiClassID;

    }

    /**

     * Identifies the menu item as "armed". If the mouse button is

     * released while it is over this item, the menu's action event

     * will fire. If the mouse button is released elsewhere, the

     * event will not fire and the menu item will be disarmed.

     *

     * @param b true to arm the menu item so it can be selected

     * @beaninfo

     *    description: Mouse release will fire an action event

     *         hidden: true

     */

    public void setArmed(boolean b) {

        ButtonModel model = (ButtonModel) getModel();

        boolean oldValue = model.isArmed();

        if(model.isArmed() != b) {

            model.setArmed(b);

        }

    }

    /**

     * Returns whether the menu item is "armed".

     *

     * @return true if the menu item is armed, and it can be selected

     * @see #setArmed

     */

    public boolean isArmed() {

        ButtonModel model = (ButtonModel) getModel();

        return model.isArmed();

    }

    /**

     * Enables or disables the menu item.

     *

     * @param b  true to enable the item

     * @beaninfo

     *    description: Does the component react to user interaction

     *          bound: true

     *      preferred: true

     */

    public void setEnabled(boolean b) {

        // Make sure we aren't armed!

        if (!b && !UIManager.getBoolean("MenuItem.disabledAreNavigable")) {

            setArmed(false);

        }

        super.setEnabled(b);

    }

    /**

     * Returns true since <code>Menu</code>s, by definition,

     * should always be on top of all other windows.  If the menu is

     * in an internal frame false is returned due to the rollover effect

     * for windows laf where the menu is not always on top.

     */

    // package private

    boolean alwaysOnTop() {

        // Fix for bug #4482165

        if (SwingUtilities.getAncestorOfClass(JInternalFrame.class, this) !=

                null) {

            return false;

        }

        return true;

    }

    /* The keystroke which acts as the menu item's accelerator

     */

    private KeyStroke accelerator;

    /**

     * Sets the key combination which invokes the menu item's

     * action listeners without navigating the menu hierarchy. It is the

     * UI's responsibility to install the correct action.  Note that

     * when the keyboard accelerator is typed, it will work whether or

     * not the menu is currently displayed.

     *

     * @param keyStroke the <code>KeyStroke</code> which will

     *          serve as an accelerator

     * @beaninfo

     *     description: The keystroke combination which will invoke the

     *                  JMenuItem's actionlisteners without navigating the

     *                  menu hierarchy

     *           bound: true

     *       preferred: true

     */

    public void setAccelerator(KeyStroke keyStroke) {

        KeyStroke oldAccelerator = accelerator;

        this.accelerator = keyStroke;

        repaint();

        revalidate();

        firePropertyChange("accelerator", oldAccelerator, accelerator);

    }

    /**

     * Returns the <code>KeyStroke</code> which serves as an accelerator

     * for the menu item.

     * @return a <code>KeyStroke</code> object identifying the

     *          accelerator key

     */

    public KeyStroke getAccelerator() {

        return this.accelerator;

    }

    /**

     * {@inheritDoc}

     *

     * @since 1.3

     */

    protected void configurePropertiesFromAction(Action a) {

        super.configurePropertiesFromAction(a);

        configureAcceleratorFromAction(a);

    }

    void setIconFromAction(Action a) {

        Icon icon = null;

        if (a != null) {

            icon = (Icon)a.getValue(Action.SMALL_ICON);

        }

        setIcon(icon);

    }

    void largeIconChanged(Action a) {

    }

    void smallIconChanged(Action a) {

        setIconFromAction(a);

    }

    void configureAcceleratorFromAction(Action a) {

        KeyStroke ks = (a==null) ? null :

            (KeyStroke)a.getValue(Action.ACCELERATOR_KEY);

        setAccelerator(ks);

    }

    /**

     * {@inheritDoc}

     * @since 1.6

     */

    protected void actionPropertyChanged(Action action, String propertyName) {

        if (propertyName == Action.ACCELERATOR_KEY) {

            configureAcceleratorFromAction(action);

        }

        else {

            super.actionPropertyChanged(action, propertyName);

        }

    }

    /**

     * Processes a mouse event forwarded from the

     * <code>MenuSelectionManager</code> and changes the menu

     * selection, if necessary, by using the

     * <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>MouseEvent</code>

     * @param path  the <code>MenuElement</code> path array

     * @param manager   the <code>MenuSelectionManager</code>

     */

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

        processMenuDragMouseEvent(

                 new MenuDragMouseEvent(e.getComponent(), e.getID(),

                                        e.getWhen(),

                                        e.getModifiers(), e.getX(), e.getY(),

                                        e.getXOnScreen(), e.getYOnScreen(),

                                        e.getClickCount(), e.isPopupTrigger(),

                                        path, manager));

    }

    /**

     * 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>

     */

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

        if (DEBUG) {

            System.out.println("in JMenuItem.processKeyEvent/3 for " + getText() +

                                   "  " + KeyStroke.getKeyStrokeForEvent(e));

        }

        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 mouse drag in a menu.

     *

     * @param e  a <code>MenuDragMouseEvent</code> object

     */

    public void processMenuDragMouseEvent(MenuDragMouseEvent e) {

        switch (e.getID()) {

        case MouseEvent.MOUSE_ENTERED:

            isMouseDragged = false; fireMenuDragMouseEntered(e); break;

        case MouseEvent.MOUSE_EXITED:

            isMouseDragged = false; fireMenuDragMouseExited(e); break;

        case MouseEvent.MOUSE_DRAGGED:

            isMouseDragged = true; fireMenuDragMouseDragged(e); break;

        case MouseEvent.MOUSE_RELEASED:

            if(isMouseDragged) fireMenuDragMouseReleased(e); break;

        default:

            break;

        }

    }

    /**

     * Handles a keystroke in a menu.

     *

     * @param e  a <code>MenuKeyEvent</code> object

     */

    public void processMenuKeyEvent(MenuKeyEvent e) {

        if (DEBUG) {

            System.out.println("in JMenuItem.processMenuKeyEvent for " + getText()+

                                   "  " + KeyStroke.getKeyStrokeForEvent(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.

     *

     * @param event a <code>MenuMouseDragEvent</code>

     * @see EventListenerList

     */

    protected void fireMenuDragMouseEntered(MenuDragMouseEvent event) {

        // 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]==MenuDragMouseListener.class) {

                // Lazily create the event:

                ((MenuDragMouseListener)listeners[i+1]).menuDragMouseEntered(event);

            }

        }

    }