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 * 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,

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 *

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package javax.swing.plaf.basic;

import javax.accessibility.AccessibleContext;

import javax.swing.*;

import javax.swing.border.Border;

import javax.swing.border.LineBorder;

import javax.swing.event.*;

import java.awt.*;

import java.awt.event.*;

import java.beans.PropertyChangeListener;

import java.beans.PropertyChangeEvent;

import java.io.Serializable;

/**

 * This is a basic implementation of the <code>ComboPopup</code> interface.

 *

 * This class represents the ui for the popup portion of the combo box.

 * <p>

 * All event handling is handled by listener classes created with the

 * <code>createxxxListener()</code> methods and internal classes.

 * You can change the behavior of this class by overriding the

 * <code>createxxxListener()</code> methods and supplying your own

 * event listeners or subclassing from the ones supplied in this class.

 * <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}.

 *

 * @author Tom Santos

 * @author Mark Davidson

 */

public class BasicComboPopup extends JPopupMenu implements ComboPopup {

    // An empty ListMode, this is used when the UI changes to allow

    // the JList to be gc'ed.

    private static class EmptyListModelClass implements ListModel,

                                                        Serializable {

        public int getSize() { return 0; }

        public Object getElementAt(int index) { return null; }

        public void addListDataListener(ListDataListener l) {}

        public void removeListDataListener(ListDataListener l) {}

    };

    static final ListModel EmptyListModel = new EmptyListModelClass();

    private static Border LIST_BORDER = new LineBorder(Color.BLACK, 1);

    protected JComboBox                comboBox;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the accessor methods instead.

     *

     * @see #getList

     * @see #createList

     */

    protected JList                    list;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the create method instead

     *

     * @see #createScroller

     */

    protected JScrollPane              scroller;

    /**

     * As of Java 2 platform v1.4 this previously undocumented field is no

     * longer used.

     */

    protected boolean                  valueIsAdjusting = false;

    // Listeners that are required by the ComboPopup interface

    /**

     * Implementation of all the listener classes.

     */

    private Handler handler;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the accessor or create methods instead.

     *

     * @see #getMouseMotionListener

     * @see #createMouseMotionListener

     */

    protected MouseMotionListener      mouseMotionListener;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the accessor or create methods instead.

     *

     * @see #getMouseListener

     * @see #createMouseListener

     */

    protected MouseListener            mouseListener;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the accessor or create methods instead.

     *

     * @see #getKeyListener

     * @see #createKeyListener

     */

    protected KeyListener              keyListener;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the create method instead.

     *

     * @see #createListSelectionListener

     */

    protected ListSelectionListener    listSelectionListener;

    // Listeners that are attached to the list

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the create method instead.

     *

     * @see #createListMouseListener

     */

    protected MouseListener            listMouseListener;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the create method instead

     *

     * @see #createListMouseMotionListener

     */

    protected MouseMotionListener      listMouseMotionListener;

    // Added to the combo box for bound properties

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the create method instead

     *

     * @see #createPropertyChangeListener

     */

    protected PropertyChangeListener   propertyChangeListener;

    // Added to the combo box model

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the create method instead

     *

     * @see #createListDataListener

     */

    protected ListDataListener         listDataListener;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override. Use the create method instead

     *

     * @see #createItemListener

     */

    protected ItemListener             itemListener;

    /**

     * This protected field is implementation specific. Do not access directly

     * or override.

     */

    protected Timer                    autoscrollTimer;

    protected boolean                  hasEntered = false;

    protected boolean                  isAutoScrolling = false;

    protected int                      scrollDirection = SCROLL_UP;

    protected static final int         SCROLL_UP = 0;

    protected static final int         SCROLL_DOWN = 1;

    //========================================

    // begin ComboPopup method implementations

    //

    /**

     * Implementation of ComboPopup.show().

     */

    public void show() {

        comboBox.firePopupMenuWillBecomeVisible();

        setListSelection(comboBox.getSelectedIndex());

        Point location = getPopupLocation();

        show( comboBox, location.x, location.y );

    }

    /**

     * Implementation of ComboPopup.hide().

     */

    public void hide() {

        MenuSelectionManager manager = MenuSelectionManager.defaultManager();

        MenuElement [] selection = manager.getSelectedPath();

        for ( int i = 0 ; i < selection.length ; i++ ) {

            if ( selection[i] == this ) {

                manager.clearSelectedPath();

                break;

            }

        }

        if (selection.length > 0) {

            comboBox.repaint();

        }

    }

    /**

     * Implementation of ComboPopup.getList().

     */

    public JList getList() {

        return list;

    }

    /**

     * Implementation of ComboPopup.getMouseListener().

     *

     * @return a <code>MouseListener</code> or null

     * @see ComboPopup#getMouseListener

     */

    public MouseListener getMouseListener() {

        if (mouseListener == null) {

            mouseListener = createMouseListener();

        }

        return mouseListener;

    }

    /**

     * Implementation of ComboPopup.getMouseMotionListener().

     *

     * @return a <code>MouseMotionListener</code> or null

     * @see ComboPopup#getMouseMotionListener

     */

    public MouseMotionListener getMouseMotionListener() {

        if (mouseMotionListener == null) {

            mouseMotionListener = createMouseMotionListener();

        }

        return mouseMotionListener;

    }

    /**

     * Implementation of ComboPopup.getKeyListener().

     *

     * @return a <code>KeyListener</code> or null

     * @see ComboPopup#getKeyListener

     */

    public KeyListener getKeyListener() {

        if (keyListener == null) {

            keyListener = createKeyListener();

        }

        return keyListener;

    }

    /**

     * Called when the UI is uninstalling.  Since this popup isn't in the component

     * tree, it won't get it's uninstallUI() called.  It removes the listeners that

     * were added in addComboBoxListeners().

     */

    public void uninstallingUI() {

        if (propertyChangeListener != null) {

            comboBox.removePropertyChangeListener( propertyChangeListener );

        }

        if (itemListener != null) {

            comboBox.removeItemListener( itemListener );

        }

        uninstallComboBoxModelListeners(comboBox.getModel());

        uninstallKeyboardActions();

        uninstallListListeners();

        // We do this, otherwise the listener the ui installs on

        // the model (the combobox model in this case) will keep a

        // reference to the list, causing the list (and us) to never get gced.

        list.setModel(EmptyListModel);

    }

    //

    // end ComboPopup method implementations

    //======================================

    /**

     * Removes the listeners from the combo box model

     *

     * @param model The combo box model to install listeners

     * @see #installComboBoxModelListeners

     */

    protected void uninstallComboBoxModelListeners( ComboBoxModel model ) {

        if (model != null && listDataListener != null) {

            model.removeListDataListener(listDataListener);

        }

    }

    protected void uninstallKeyboardActions() {

        // XXX - shouldn't call this method

//        comboBox.unregisterKeyboardAction( KeyStroke.getKeyStroke( KeyEvent.VK_ENTER, 0 ) );

    }

    //===================================================================

    // begin Initialization routines

    //

    public BasicComboPopup( JComboBox combo ) {

        super();

        setName("ComboPopup.popup");

        comboBox = combo;

        setLightWeightPopupEnabled( comboBox.isLightWeightPopupEnabled() );

        // UI construction of the popup.

        list = createList();

        list.setName("ComboBox.list");

        configureList();

        scroller = createScroller();

        scroller.setName("ComboBox.scrollPane");

        configureScroller();

        configurePopup();

        installComboBoxListeners();

        installKeyboardActions();

    }

    // Overriden PopupMenuListener notification methods to inform combo box

    // PopupMenuListeners.

    protected void firePopupMenuWillBecomeVisible() {

        super.firePopupMenuWillBecomeVisible();

        // comboBox.firePopupMenuWillBecomeVisible() is called from BasicComboPopup.show() method

        // to let the user change the popup menu from the PopupMenuListener.popupMenuWillBecomeVisible()

    }

    protected void firePopupMenuWillBecomeInvisible() {

        super.firePopupMenuWillBecomeInvisible();

        comboBox.firePopupMenuWillBecomeInvisible();

    }

    protected void firePopupMenuCanceled() {

        super.firePopupMenuCanceled();

        comboBox.firePopupMenuCanceled();

    }

    /**

     * Creates a listener

     * that will watch for mouse-press and release events on the combo box.

     *

     * <strong>Warning:</strong>

     * When overriding this method, make sure to maintain the existing

     * behavior.

     *

     * @return a <code>MouseListener</code> which will be added to

     * the combo box or null

     */

    protected MouseListener createMouseListener() {

        return getHandler();

    }

    /**

     * Creates the mouse motion listener which will be added to the combo

     * box.

     *

     * <strong>Warning:</strong>

     * When overriding this method, make sure to maintain the existing

     * behavior.

     *

     * @return a <code>MouseMotionListener</code> which will be added to

     *         the combo box or null

     */

    protected MouseMotionListener createMouseMotionListener() {

        return getHandler();

    }

    /**

     * Creates the key listener that will be added to the combo box. If

     * this method returns null then it will not be added to the combo box.

     *

     * @return a <code>KeyListener</code> or null

     */

    protected KeyListener createKeyListener() {

        return null;

    }

    /**

     * Creates a list selection listener that watches for selection changes in

     * the popup's list.  If this method returns null then it will not

     * be added to the popup list.

     *

     * @return an instance of a <code>ListSelectionListener</code> or null

     */

    protected ListSelectionListener createListSelectionListener() {

        return null;

    }

    /**

     * Creates a list data listener which will be added to the

     * <code>ComboBoxModel</code>. If this method returns null then

     * it will not be added to the combo box model.

     *

     * @return an instance of a <code>ListDataListener</code> or null

     */

    protected ListDataListener createListDataListener() {

        return null;

    }

    /**

     * Creates a mouse listener that watches for mouse events in

     * the popup's list. If this method returns null then it will

     * not be added to the combo box.

     *

     * @return an instance of a <code>MouseListener</code> or null

     */

    protected MouseListener createListMouseListener() {

        return getHandler();

    }

    /**

     * Creates a mouse motion listener that watches for mouse motion

     * events in the popup's list. If this method returns null then it will

     * not be added to the combo box.

     *

     * @return an instance of a <code>MouseMotionListener</code> or null

     */

    protected MouseMotionListener createListMouseMotionListener() {

        return getHandler();

    }

    /**

     * Creates a <code>PropertyChangeListener</code> which will be added to

     * the combo box. If this method returns null then it will not

     * be added to the combo box.

     *

     * @return an instance of a <code>PropertyChangeListener</code> or null

     */

    protected PropertyChangeListener createPropertyChangeListener() {

        return getHandler();

    }

    /**

     * Creates an <code>ItemListener</code> which will be added to the

     * combo box. If this method returns null then it will not

     * be added to the combo box.

     * <p>

     * Subclasses may override this method to return instances of their own

     * ItemEvent handlers.

     *

     * @return an instance of an <code>ItemListener</code> or null

     */

    protected ItemListener createItemListener() {

        return getHandler();

    }

    private Handler getHandler() {

        if (handler == null) {

            handler = new Handler();

        }

        return handler;

    }

    /**

     * Creates the JList used in the popup to display

     * the items in the combo box model. This method is called when the UI class

     * is created.

     *

     * @return a <code>JList</code> used to display the combo box items

     */

    protected JList createList() {

        return new JList( comboBox.getModel() ) {

            public void processMouseEvent(MouseEvent e)  {

                if (BasicGraphicsUtils.isMenuShortcutKeyDown(e))  {

                    // Fix for 4234053. Filter out the Control Key from the list.

                    // ie., don't allow CTRL key deselection.

                    Toolkit toolkit = Toolkit.getDefaultToolkit();

                    e = new MouseEvent((Component)e.getSource(), e.getID(), e.getWhen(),

                                       e.getModifiers() ^ toolkit.getMenuShortcutKeyMask(),

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

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

                                       e.getClickCount(),

                                       e.isPopupTrigger(),

                                       MouseEvent.NOBUTTON);

                }

                super.processMouseEvent(e);

            }

        };

    }

    /**

     * Configures the list which is used to hold the combo box items in the

     * popup. This method is called when the UI class

     * is created.

     *

     * @see #createList

     */

    protected void configureList() {

        list.setFont( comboBox.getFont() );

        list.setForeground( comboBox.getForeground() );

        list.setBackground( comboBox.getBackground() );

        list.setSelectionForeground( UIManager.getColor( "ComboBox.selectionForeground" ) );

        list.setSelectionBackground( UIManager.getColor( "ComboBox.selectionBackground" ) );

        list.setBorder( null );

        list.setCellRenderer( comboBox.getRenderer() );

        list.setFocusable( false );

        list.setSelectionMode( ListSelectionModel.SINGLE_SELECTION );

        setListSelection( comboBox.getSelectedIndex() );

        installListListeners();

    }

    /**

     * Adds the listeners to the list control.