basiccombopopup.java

java jdk 1.4的源码

/*
 * @(#)BasicComboPopup.java	1.73 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.swing.plaf.basic;

import javax.swing.*;
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}.
 *
 * @version 1.73 01/23/03
 * @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.
    static final ListModel EmptyListModel = new ListModel() {
	public int getSize() { return 0; }
	public Object getElementAt(int index) { return null; }
	public void addListDataListener(ListDataListener l) {}
	public void removeListDataListener(ListDataListener l) {}
    };

    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
    /**
     * 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() {
	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();
        comboBox = combo;

	installComboBoxListeners();
        setLightWeightPopupEnabled( comboBox.isLightWeightPopupEnabled() );

	// UI construction of the popup. 
        list = createList();
	configureList();
        scroller = createScroller();
        configureScroller();
        configurePopup();

        installKeyboardActions();
    }

    // Overriden PopupMenuListener notification methods to inform combo box
    // PopupMenuListeners.

    protected void firePopupMenuWillBecomeVisible() {
	super.firePopupMenuWillBecomeVisible();
	comboBox.firePopupMenuWillBecomeVisible();
    }
    
    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 new InvocationMouseHandler();
    }

    /**
     * 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 new InvocationMouseMotionHandler();
    }

    /**
     * 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