/*
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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,
 * 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.plaf.basic;


import sun.swing.DefaultLookup;
import sun.swing.UIAction;

import java.awt.*;
import java.awt.event.*;

import java.beans.*;

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.plaf.*;


Implementation of ScrollBarUI for the Basic Look and Feel
Author:
Rich Schiavi, David Kloba, Hans Muller/**
 * Implementation of ScrollBarUI for the Basic Look and Feel
 *
 * @author Rich Schiavi
 * @author David Kloba
 * @author Hans Muller
 */
public class BasicScrollBarUI
    extends ScrollBarUI implements LayoutManager, SwingConstants
{
    private static final int POSITIVE_SCROLL = 1;
    private static final int NEGATIVE_SCROLL = -1;

    private static final int MIN_SCROLL = 2;
    private static final int MAX_SCROLL = 3;

    // NOTE: DO NOT use this field directly, SynthScrollBarUI assumes you'll
    // call getMinimumThumbSize to access it.
    protected Dimension minimumThumbSize;
    protected Dimension maximumThumbSize;

    protected Color thumbHighlightColor;
    protected Color thumbLightShadowColor;
    protected Color thumbDarkShadowColor;
    protected Color thumbColor;
    protected Color trackColor;
    protected Color trackHighlightColor;

    protected JScrollBar scrollbar;
    protected JButton incrButton;
    protected JButton decrButton;
    protected boolean isDragging;
    protected TrackListener trackListener;
    protected ArrowButtonListener buttonListener;
    protected ModelListener modelListener;

    protected Rectangle thumbRect;
    protected Rectangle trackRect;

    protected int trackHighlight;

    protected static final int NO_HIGHLIGHT = 0;
    protected static final int DECREASE_HIGHLIGHT = 1;
    protected static final int INCREASE_HIGHLIGHT = 2;

    protected ScrollListener scrollListener;
    protected PropertyChangeListener propertyChangeListener;
    protected Timer scrollTimer;

    private final static int scrollSpeedThrottle = 60; // delay in milli seconds

    
True indicates a middle click will absolutely position the
scrollbar. /** True indicates a middle click will absolutely position the
     * scrollbar. */
    private boolean supportsAbsolutePositioning;

    
Hint as to what width (when vertical) or height (when horizontal)
should be.
/** Hint as to what width (when vertical) or height (when horizontal)
     * should be.
     */
    private int scrollBarWidth;

    private Handler handler;

    private boolean thumbActive;

    
Determine whether scrollbar layout should use cached value or adjusted
value returned by scrollbar's getValue.
/**
     * Determine whether scrollbar layout should use cached value or adjusted
     * value returned by scrollbar's <code>getValue</code>.
     */
    private boolean useCachedValue = false;
    
The scrollbar value is cached to save real value if the view is adjusted.
/**
     * The scrollbar value is cached to save real value if the view is adjusted.
     */
    private int scrollBarValue;

    
Distance between the increment button and the track. This may be a negative
number. If negative, then an overlap between the button and track will occur,
which is useful for shaped buttons.
TODO This should be made protected in a feature release
/**
     * Distance between the increment button and the track. This may be a negative
     * number. If negative, then an overlap between the button and track will occur,
     * which is useful for shaped buttons.
     *
     * TODO This should be made protected in a feature release
     */
    private int incrGap;

    
Distance between the decrement button and the track. This may be a negative
number. If negative, then an overlap between the button and track will occur,
which is useful for shaped buttons.
TODO This should be made protected in a feature release
/**
     * Distance between the decrement button and the track. This may be a negative
     * number. If negative, then an overlap between the button and track will occur,
     * which is useful for shaped buttons.
     *
     * TODO This should be made protected in a feature release
     */
    private int decrGap;

    static void loadActionMap(LazyActionMap map) {
        map.put(new Actions(Actions.POSITIVE_UNIT_INCREMENT));
        map.put(new Actions(Actions.POSITIVE_BLOCK_INCREMENT));
        map.put(new Actions(Actions.NEGATIVE_UNIT_INCREMENT));
        map.put(new Actions(Actions.NEGATIVE_BLOCK_INCREMENT));
        map.put(new Actions(Actions.MIN_SCROLL));
        map.put(new Actions(Actions.MAX_SCROLL));
    }


    public static ComponentUI createUI(JComponent c)    {
        return new BasicScrollBarUI();
    }


    protected void configureScrollBarColors()
    {
        LookAndFeel.installColors(scrollbar, "ScrollBar.background",
                                  "ScrollBar.foreground");
        thumbHighlightColor = UIManager.getColor("ScrollBar.thumbHighlight");
        thumbLightShadowColor = UIManager.getColor("ScrollBar.thumbShadow");
        thumbDarkShadowColor = UIManager.getColor("ScrollBar.thumbDarkShadow");
        thumbColor = UIManager.getColor("ScrollBar.thumb");
        trackColor = UIManager.getColor("ScrollBar.track");
        trackHighlightColor = UIManager.getColor("ScrollBar.trackHighlight");
    }


    public void installUI(JComponent c)   {
        scrollbar = (JScrollBar)c;
        thumbRect = new Rectangle(0, 0, 0, 0);
        trackRect = new Rectangle(0, 0, 0, 0);
        installDefaults();
        installComponents();
        installListeners();
        installKeyboardActions();
    }

    public void uninstallUI(JComponent c) {
        scrollbar = (JScrollBar)c;
        uninstallListeners();
        uninstallDefaults();
        uninstallComponents();
        uninstallKeyboardActions();
        thumbRect = null;
        scrollbar = null;
        incrButton = null;
        decrButton = null;
    }


    protected void installDefaults()
    {
        scrollBarWidth = UIManager.getInt("ScrollBar.width");
        if (scrollBarWidth <= 0) {
            scrollBarWidth = 16;
        }
        minimumThumbSize = (Dimension)UIManager.get("ScrollBar.minimumThumbSize");
        maximumThumbSize = (Dimension)UIManager.get("ScrollBar.maximumThumbSize");

        Boolean absB = (Boolean)UIManager.get("ScrollBar.allowsAbsolutePositioning");
        supportsAbsolutePositioning = (absB != null) ? absB.booleanValue() :
                                      false;

        trackHighlight = NO_HIGHLIGHT;
        if (scrollbar.getLayout() == null ||
                     (scrollbar.getLayout() instanceof UIResource)) {
            scrollbar.setLayout(this);
        }
        configureScrollBarColors();
        LookAndFeel.installBorder(scrollbar, "ScrollBar.border");
        LookAndFeel.installProperty(scrollbar, "opaque", Boolean.TRUE);

        scrollBarValue = scrollbar.getValue();

        incrGap = UIManager.getInt("ScrollBar.incrementButtonGap");
        decrGap = UIManager.getInt("ScrollBar.decrementButtonGap");

        // TODO this can be removed when incrGap/decrGap become protected
        // handle scaling for sizeVarients for special case components. The
        // key "JComponent.sizeVariant" scales for large/small/mini
        // components are based on Apples LAF
        String scaleKey = (String)scrollbar.getClientProperty(
                "JComponent.sizeVariant");
        if (scaleKey != null){
            if ("large".equals(scaleKey)){
                scrollBarWidth *= 1.15;
                incrGap *= 1.15;
                decrGap *= 1.15;
            } else if ("small".equals(scaleKey)){
                scrollBarWidth *= 0.857;
                incrGap *= 0.857;
                decrGap *= 0.714;
            } else if ("mini".equals(scaleKey)){
                scrollBarWidth *= 0.714;
                incrGap *= 0.714;
                decrGap *= 0.714;
            }
        }
    }


    protected void installComponents(){
        switch (scrollbar.getOrientation()) {
        case JScrollBar.VERTICAL:
            incrButton = createIncreaseButton(SOUTH);
            decrButton = createDecreaseButton(NORTH);
            break;

        case JScrollBar.HORIZONTAL:
            if (scrollbar.getComponentOrientation().isLeftToRight()) {
                incrButton = createIncreaseButton(EAST);
                decrButton = createDecreaseButton(WEST);
            } else {
                incrButton = createIncreaseButton(WEST);
                decrButton = createDecreaseButton(EAST);
            }
            break;
        }
        scrollbar.add(incrButton);
        scrollbar.add(decrButton);
        // Force the children's enabled state to be updated.
        scrollbar.setEnabled(scrollbar.isEnabled());
    }

    protected void uninstallComponents(){
        scrollbar.remove(incrButton);
        scrollbar.remove(decrButton);
    }


    protected void installListeners(){
        trackListener = createTrackListener();
        buttonListener = createArrowButtonListener();
        modelListener = createModelListener();
        propertyChangeListener = createPropertyChangeListener();

        scrollbar.addMouseListener(trackListener);
        scrollbar.addMouseMotionListener(trackListener);
        scrollbar.getModel().addChangeListener(modelListener);
        scrollbar.addPropertyChangeListener(propertyChangeListener);
        scrollbar.addFocusListener(getHandler());

        if (incrButton != null) {
            incrButton.addMouseListener(buttonListener);
        }
        if (decrButton != null) {
            decrButton.addMouseListener(buttonListener);
        }

        scrollListener = createScrollListener();
        scrollTimer = new Timer(scrollSpeedThrottle, scrollListener);
        scrollTimer.setInitialDelay(300);  // default InitialDelay?
    }


    protected void installKeyboardActions(){
        LazyActionMap.installLazyActionMap(scrollbar, BasicScrollBarUI.class,
                                           "ScrollBar.actionMap");

        InputMap inputMap = getInputMap(JComponent.WHEN_FOCUSED);
        SwingUtilities.replaceUIInputMap(scrollbar, JComponent.WHEN_FOCUSED,
                                         inputMap);
        inputMap = getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
        SwingUtilities.replaceUIInputMap(scrollbar,
                   JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, inputMap);
    }

    protected void uninstallKeyboardActions(){
        SwingUtilities.replaceUIInputMap(scrollbar, JComponent.WHEN_FOCUSED,
                                         null);
        SwingUtilities.replaceUIActionMap(scrollbar, null);
    }

    private InputMap getInputMap(int condition) {
        if (condition == JComponent.WHEN_FOCUSED) {
            InputMap keyMap = (InputMap)DefaultLookup.get(
                        scrollbar, this, "ScrollBar.focusInputMap");
            InputMap rtlKeyMap;

            if (scrollbar.getComponentOrientation().isLeftToRight() ||
                ((rtlKeyMap = (InputMap)DefaultLookup.get(scrollbar, this, "ScrollBar.focusInputMap.RightToLeft")) == null)) {
                return keyMap;
            } else {
                rtlKeyMap.setParent(keyMap);
                return rtlKeyMap;
            }
        }
        else if (condition == JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT) {
            InputMap keyMap = (InputMap)DefaultLookup.get(
                        scrollbar, this, "ScrollBar.ancestorInputMap");
            InputMap rtlKeyMap;

            if (scrollbar.getComponentOrientation().isLeftToRight() ||
                ((rtlKeyMap = (InputMap)DefaultLookup.get(scrollbar, this, "ScrollBar.ancestorInputMap.RightToLeft")) == null)) {
                return keyMap;
            } else {
                rtlKeyMap.setParent(keyMap);
                return rtlKeyMap;
            }
        }
        return null;
    }


    protected void uninstallListeners() {
        scrollTimer.stop();
        scrollTimer = null;

        if (decrButton != null){
            decrButton.removeMouseListener(buttonListener);
        }
        if (incrButton != null){
            incrButton.removeMouseListener(buttonListener);
        }

        scrollbar.getModel().removeChangeListener(modelListener);
        scrollbar.removeMouseListener(trackListener);
        scrollbar.removeMouseMotionListener(trackListener);
        scrollbar.removePropertyChangeListener(propertyChangeListener);
        scrollbar.removeFocusListener(getHandler());
        handler = null;
    }


    protected void uninstallDefaults(){
        LookAndFeel.uninstallBorder(scrollbar);
        if (scrollbar.getLayout() == this) {
            scrollbar.setLayout(null);
        }
    }


    private Handler getHandler() {
        if (handler == null) {
            handler = new Handler();
        }
        return handler;
    }

    protected TrackListener createTrackListener(){
        return new TrackListener();
    }

    protected ArrowButtonListener createArrowButtonListener(){
        return new ArrowButtonListener();
    }

    protected ModelListener createModelListener(){
        return new ModelListener();
    }

    protected ScrollListener createScrollListener(){
        return new ScrollListener();
    }

    protected PropertyChangeListener createPropertyChangeListener() {
        return getHandler();
    }

    private void updateThumbState(int x, int y) {
        Rectangle rect = getThumbBounds();

        setThumbRollover(rect.contains(x, y));
    }

    
Sets whether or not the mouse is currently over the thumb.
Params:
active – True indicates the thumb is currently active.
Since:
1.5/**
     * Sets whether or not the mouse is currently over the thumb.
     *
     * @param active True indicates the thumb is currently active.
     * @since 1.5
     */
    protected void setThumbRollover(boolean active) {
        if (thumbActive != active) {
            thumbActive = active;
            scrollbar.repaint(getThumbBounds());
        }
    }

    
Returns true if the mouse is currently over the thumb.
Returns:
true if the thumb is currently active
Since:
1.5/**
     * Returns true if the mouse is currently over the thumb.
     *
     * @return true if the thumb is currently active
     * @since 1.5
     */
    public boolean isThumbRollover() {
        return thumbActive;
    }

    public void paint(Graphics g, JComponent c) {
        paintTrack(g, c, getTrackBounds());
        Rectangle thumbBounds = getThumbBounds();
        if (thumbBounds.intersects(g.getClipBounds())) {
            paintThumb(g, c, thumbBounds);
        }
    }


    
A vertical scrollbar's preferred width is the maximum of
preferred widths of the (non null)
increment/decrement buttons,
and the minimum width of the thumb. The preferred height is the
sum of the preferred heights of the same parts.  The basis for
the preferred size of a horizontal scrollbar is similar.

The preferredSize is only computed once, subsequent
calls to this method just return a cached size.
Params:
c – the JScrollBar that's delegating this method to us
See Also:
getMaximumSize
ComponentUI.getMinimumSize
Returns:
the preferred size of a Basic JScrollBar/**
     * A vertical scrollbar's preferred width is the maximum of
     * preferred widths of the (non <code>null</code>)
     * increment/decrement buttons,
     * and the minimum width of the thumb. The preferred height is the
     * sum of the preferred heights of the same parts.  The basis for
     * the preferred size of a horizontal scrollbar is similar.
     * <p>
     * The <code>preferredSize</code> is only computed once, subsequent
     * calls to this method just return a cached size.
     *
     * @param c the <code>JScrollBar</code> that's delegating this method to us
     * @return the preferred size of a Basic JScrollBar
     * @see #getMaximumSize
     * @see #getMinimumSize
     */
    public Dimension getPreferredSize(JComponent c) {
        return (scrollbar.getOrientation() == JScrollBar.VERTICAL)
            ? new Dimension(scrollBarWidth, 48)
            : new Dimension(48, scrollBarWidth);
    }


    
Params:
c – The JScrollBar that's delegating this method to us.
See Also:
ComponentUI.getMinimumSize
getPreferredSize
Returns:
new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);/**
     * @param c The JScrollBar that's delegating this method to us.
     * @return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
     * @see #getMinimumSize
     * @see #getPreferredSize
     */
    public Dimension getMaximumSize(JComponent c) {
        return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
    }

    protected JButton createDecreaseButton(int orientation)  {
        return new BasicArrowButton(orientation,
                                    UIManager.getColor("ScrollBar.thumb"),
                                    UIManager.getColor("ScrollBar.thumbShadow"),
                                    UIManager.getColor("ScrollBar.thumbDarkShadow"),
                                    UIManager.getColor("ScrollBar.thumbHighlight"));
    }

    protected JButton createIncreaseButton(int orientation)  {
        return new BasicArrowButton(orientation,
                                    UIManager.getColor("ScrollBar.thumb"),
                                    UIManager.getColor("ScrollBar.thumbShadow"),
                                    UIManager.getColor("ScrollBar.thumbDarkShadow"),
                                    UIManager.getColor("ScrollBar.thumbHighlight"));
    }


    protected void paintDecreaseHighlight(Graphics g)
    {
        Insets insets = scrollbar.getInsets();
        Rectangle thumbR = getThumbBounds();
        g.setColor(trackHighlightColor);

        if (scrollbar.getOrientation() == JScrollBar.VERTICAL) {
            //paint the distance between the start of the track and top of the thumb
            int x = insets.left;
            int y = trackRect.y;
            int w = scrollbar.getWidth() - (insets.left + insets.right);
            int h = thumbR.y - y;
            g.fillRect(x, y, w, h);
        } else {
            //if left-to-right, fill the area between the start of the track and
            //the left edge of the thumb. If right-to-left, fill the area between
            //the end of the thumb and end of the track.
            int x, w;
            if (scrollbar.getComponentOrientation().isLeftToRight()) {
               x = trackRect.x;
                w = thumbR.x - x;
            } else {
                x = thumbR.x + thumbR.width;
                w = trackRect.x + trackRect.width - x;
            }
            int y = insets.top;
            int h = scrollbar.getHeight() - (insets.top + insets.bottom);
            g.fillRect(x, y, w, h);
        }
    }


    protected void paintIncreaseHighlight(Graphics g)
    {
        Insets insets = scrollbar.getInsets();
        Rectangle thumbR = getThumbBounds();
        g.setColor(trackHighlightColor);

        if (scrollbar.getOrientation() == JScrollBar.VERTICAL) {
            //fill the area between the bottom of the thumb and the end of the track.
            int x = insets.left;
            int y = thumbR.y + thumbR.height;
            int w = scrollbar.getWidth() - (insets.left + insets.right);
            int h = trackRect.y + trackRect.height - y;
            g.fillRect(x, y, w, h);
        }
        else {
            //if left-to-right, fill the area between the right of the thumb and the
            //end of the track. If right-to-left, then fill the area to the left of
            //the thumb and the start of the track.
            int x, w;
            if (scrollbar.getComponentOrientation().isLeftToRight()) {
                x = thumbR.x + thumbR.width;
                w = trackRect.x + trackRect.width - x;
            } else {
                x = trackRect.x;
                w = thumbR.x - x;
            }
            int y = insets.top;
            int h = scrollbar.getHeight() - (insets.top + insets.bottom);
            g.fillRect(x, y, w, h);
        }
    }


    protected void paintTrack(Graphics g, JComponent c, Rectangle trackBounds)
    {
        g.setColor(trackColor);
        g.fillRect(trackBounds.x, trackBounds.y, trackBounds.width, trackBounds.height);

        if(trackHighlight == DECREASE_HIGHLIGHT)        {
            paintDecreaseHighlight(g);
        }
        else if(trackHighlight == INCREASE_HIGHLIGHT)           {
            paintIncreaseHighlight(g);
        }
    }


    protected void paintThumb(Graphics g, JComponent c, Rectangle thumbBounds)
    {
        if(thumbBounds.isEmpty() || !scrollbar.isEnabled())     {
            return;
        }

        int w = thumbBounds.width;
        int h = thumbBounds.height;

        g.translate(thumbBounds.x, thumbBounds.y);

        g.setColor(thumbDarkShadowColor);
        g.drawRect(0, 0, w-1, h-1);
        g.setColor(thumbColor);
        g.fillRect(0, 0, w-1, h-1);

        g.setColor(thumbHighlightColor);
        g.drawLine(1, 1, 1, h-2);
        g.drawLine(2, 1, w-3, 1);

        g.setColor(thumbLightShadowColor);
        g.drawLine(2, h-2, w-2, h-2);
        g.drawLine(w-2, 1, w-2, h-3);

        g.translate(-thumbBounds.x, -thumbBounds.y);
    }


    
Return the smallest acceptable size for the thumb.  If the scrollbar
becomes so small that this size isn't available, the thumb will be
hidden.

Warning : the value returned by this method should not be
be modified, it's a shared static constant.
See Also:
getMaximumThumbSize
Returns:
The smallest acceptable size for the thumb./**
     * Return the smallest acceptable size for the thumb.  If the scrollbar
     * becomes so small that this size isn't available, the thumb will be
     * hidden.
     * <p>
     * <b>Warning </b>: the value returned by this method should not be
     * be modified, it's a shared static constant.
     *
     * @return The smallest acceptable size for the thumb.
     * @see #getMaximumThumbSize
     */
    protected Dimension getMinimumThumbSize() {
        return minimumThumbSize;
    }

    
Return the largest acceptable size for the thumb.  To create a fixed
size thumb one make this method and getMinimumThumbSize
return the same value.

Warning : the value returned by this method should not be
be modified, it's a shared static constant.
See Also:
getMinimumThumbSize
Returns:
The largest acceptable size for the thumb./**
     * Return the largest acceptable size for the thumb.  To create a fixed
     * size thumb one make this method and <code>getMinimumThumbSize</code>
     * return the same value.
     * <p>
     * <b>Warning </b>: the value returned by this method should not be
     * be modified, it's a shared static constant.
     *
     * @return The largest acceptable size for the thumb.
     * @see #getMinimumThumbSize
     */
    protected Dimension getMaximumThumbSize()   {
        return maximumThumbSize;
    }


    /*
     * LayoutManager Implementation
     */

    public void addLayoutComponent(String name, Component child) {}
    public void removeLayoutComponent(Component child) {}

    public Dimension preferredLayoutSize(Container scrollbarContainer)  {
        return getPreferredSize((JComponent)scrollbarContainer);
    }

    public Dimension minimumLayoutSize(Container scrollbarContainer) {
        return getMinimumSize((JComponent)scrollbarContainer);
    }

    private int getValue(JScrollBar sb) {
        return (useCachedValue) ? scrollBarValue : sb.getValue();
    }

    protected void layoutVScrollbar(JScrollBar sb)
    {
        Dimension sbSize = sb.getSize();
        Insets sbInsets = sb.getInsets();

        /*
         * Width and left edge of the buttons and thumb.
         */
        int itemW = sbSize.width - (sbInsets.left + sbInsets.right);
        int itemX = sbInsets.left;

        /* Nominal locations of the buttons, assuming their preferred
         * size will fit.
         */
        boolean squareButtons = DefaultLookup.getBoolean(
            scrollbar, this, "ScrollBar.squareButtons", false);
        int decrButtonH = squareButtons ? itemW :
                          decrButton.getPreferredSize().height;
        int decrButtonY = sbInsets.top;

        int incrButtonH = squareButtons ? itemW :
                          incrButton.getPreferredSize().height;
        int incrButtonY = sbSize.height - (sbInsets.bottom + incrButtonH);

        /* The thumb must fit within the height left over after we
         * subtract the preferredSize of the buttons and the insets
         * and the gaps
         */
        int sbInsetsH = sbInsets.top + sbInsets.bottom;
        int sbButtonsH = decrButtonH + incrButtonH;
        int gaps = decrGap + incrGap;
        float trackH = sbSize.height - (sbInsetsH + sbButtonsH) - gaps;

        /* Compute the height and origin of the thumb.   The case
         * where the thumb is at the bottom edge is handled specially
         * to avoid numerical problems in computing thumbY.  Enforce
         * the thumbs min/max dimensions.  If the thumb doesn't
         * fit in the track (trackH) we'll hide it later.
         */
        float min = sb.getMinimum();
        float extent = sb.getVisibleAmount();
        float range = sb.getMaximum() - min;
        float value = getValue(sb);

        int thumbH = (range <= 0)
            ? getMaximumThumbSize().height : (int)(trackH * (extent / range));
        thumbH = Math.max(thumbH, getMinimumThumbSize().height);
        thumbH = Math.min(thumbH, getMaximumThumbSize().height);

        int thumbY = incrButtonY - incrGap - thumbH;
        if (value < (sb.getMaximum() - sb.getVisibleAmount())) {
            float thumbRange = trackH - thumbH;
            thumbY = (int)(0.5f + (thumbRange * ((value - min) / (range - extent))));
            thumbY +=  decrButtonY + decrButtonH + decrGap;
        }

        /* If the buttons don't fit, allocate half of the available
         * space to each and move the lower one (incrButton) down.
         */
        int sbAvailButtonH = (sbSize.height - sbInsetsH);
        if (sbAvailButtonH < sbButtonsH) {
            incrButtonH = decrButtonH = sbAvailButtonH / 2;
            incrButtonY = sbSize.height - (sbInsets.bottom + incrButtonH);
        }
        decrButton.setBounds(itemX, decrButtonY, itemW, decrButtonH);
        incrButton.setBounds(itemX, incrButtonY, itemW, incrButtonH);

        /* Update the trackRect field.
         */
        int itrackY = decrButtonY + decrButtonH + decrGap;
        int itrackH = incrButtonY - incrGap - itrackY;
        trackRect.setBounds(itemX, itrackY, itemW, itrackH);

        /* If the thumb isn't going to fit, zero it's bounds.  Otherwise
         * make sure it fits between the buttons.  Note that setting the
         * thumbs bounds will cause a repaint.
         */
        if(thumbH >= (int)trackH)       {
            if (UIManager.getBoolean("ScrollBar.alwaysShowThumb")) {
                // This is used primarily for GTK L&F, which expands the
                // thumb to fit the track when it would otherwise be hidden.
                setThumbBounds(itemX, itrackY, itemW, itrackH);
            } else {
                // Other L&F's simply hide the thumb in this case.
                setThumbBounds(0, 0, 0, 0);
            }
        }
        else {
            if ((thumbY + thumbH) > incrButtonY - incrGap) {
                thumbY = incrButtonY - incrGap - thumbH;
            }
            if (thumbY  < (decrButtonY + decrButtonH + decrGap)) {
                thumbY = decrButtonY + decrButtonH + decrGap + 1;
            }
            setThumbBounds(itemX, thumbY, itemW, thumbH);
        }
    }


    protected void layoutHScrollbar(JScrollBar sb)
    {
        Dimension sbSize = sb.getSize();
        Insets sbInsets = sb.getInsets();

        /* Height and top edge of the buttons and thumb.
         */
        int itemH = sbSize.height - (sbInsets.top + sbInsets.bottom);
        int itemY = sbInsets.top;

        boolean ltr = sb.getComponentOrientation().isLeftToRight();

        /* Nominal locations of the buttons, assuming their preferred
         * size will fit.
         */
        boolean squareButtons = DefaultLookup.getBoolean(
            scrollbar, this, "ScrollBar.squareButtons", false);
        int leftButtonW = squareButtons ? itemH :
                          decrButton.getPreferredSize().width;
        int rightButtonW = squareButtons ? itemH :
                          incrButton.getPreferredSize().width;
        if (!ltr) {
            int temp = leftButtonW;
            leftButtonW = rightButtonW;
            rightButtonW = temp;
        }
        int leftButtonX = sbInsets.left;
        int rightButtonX = sbSize.width - (sbInsets.right + rightButtonW);
        int leftGap = ltr ? decrGap : incrGap;
        int rightGap = ltr ? incrGap : decrGap;

        /* The thumb must fit within the width left over after we
         * subtract the preferredSize of the buttons and the insets
         * and the gaps
         */
        int sbInsetsW = sbInsets.left + sbInsets.right;
        int sbButtonsW = leftButtonW + rightButtonW;
        float trackW = sbSize.width - (sbInsetsW + sbButtonsW) - (leftGap + rightGap);

        /* Compute the width and origin of the thumb.  Enforce
         * the thumbs min/max dimensions.  The case where the thumb
         * is at the right edge is handled specially to avoid numerical
         * problems in computing thumbX.  If the thumb doesn't
         * fit in the track (trackH) we'll hide it later.
         */
        float min = sb.getMinimum();
        float max = sb.getMaximum();
        float extent = sb.getVisibleAmount();
        float range = max - min;
        float value = getValue(sb);

        int thumbW = (range <= 0)
            ? getMaximumThumbSize().width : (int)(trackW * (extent / range));
        thumbW = Math.max(thumbW, getMinimumThumbSize().width);
        thumbW = Math.min(thumbW, getMaximumThumbSize().width);

        int thumbX = ltr ? rightButtonX - rightGap - thumbW : leftButtonX + leftButtonW + leftGap;
        if (value < (max - sb.getVisibleAmount())) {
            float thumbRange = trackW - thumbW;
            if( ltr ) {
                thumbX = (int)(0.5f + (thumbRange * ((value - min) / (range - extent))));
            } else {
                thumbX = (int)(0.5f + (thumbRange * ((max - extent - value) / (range - extent))));
            }
            thumbX += leftButtonX + leftButtonW + leftGap;
        }

        /* If the buttons don't fit, allocate half of the available
         * space to each and move the right one over.
         */
        int sbAvailButtonW = (sbSize.width - sbInsetsW);
        if (sbAvailButtonW < sbButtonsW) {
            rightButtonW = leftButtonW = sbAvailButtonW / 2;
            rightButtonX = sbSize.width - (sbInsets.right + rightButtonW + rightGap);
        }

        (ltr ? decrButton : incrButton).setBounds(leftButtonX, itemY, leftButtonW, itemH);
        (ltr ? incrButton : decrButton).setBounds(rightButtonX, itemY, rightButtonW, itemH);

        /* Update the trackRect field.
         */
        int itrackX = leftButtonX + leftButtonW + leftGap;
        int itrackW = rightButtonX - rightGap - itrackX;
        trackRect.setBounds(itrackX, itemY, itrackW, itemH);

        /* Make sure the thumb fits between the buttons.  Note
         * that setting the thumbs bounds causes a repaint.
         */
        if (thumbW >= (int)trackW) {
            if (UIManager.getBoolean("ScrollBar.alwaysShowThumb")) {
                // This is used primarily for GTK L&F, which expands the
                // thumb to fit the track when it would otherwise be hidden.
                setThumbBounds(itrackX, itemY, itrackW, itemH);
            } else {
                // Other L&F's simply hide the thumb in this case.
                setThumbBounds(0, 0, 0, 0);
            }
        }
        else {
            if (thumbX + thumbW > rightButtonX - rightGap) {
                thumbX = rightButtonX - rightGap - thumbW;
            }
            if (thumbX  < leftButtonX + leftButtonW + leftGap) {
                thumbX = leftButtonX + leftButtonW + leftGap + 1;
            }
            setThumbBounds(thumbX, itemY, thumbW, itemH);
        }
    }

    public void layoutContainer(Container scrollbarContainer)
    {
        /* If the user is dragging the value, we'll assume that the
         * scrollbars layout is OK modulo the thumb which is being
         * handled by the dragging code.
         */
        if (isDragging) {
            return;
        }

        JScrollBar scrollbar = (JScrollBar)scrollbarContainer;
        switch (scrollbar.getOrientation()) {
        case JScrollBar.VERTICAL:
            layoutVScrollbar(scrollbar);
            break;

        case JScrollBar.HORIZONTAL:
            layoutHScrollbar(scrollbar);
            break;
        }
    }


    
Set the bounds of the thumb and force a repaint that includes
the old thumbBounds and the new one.
See Also:
getThumbBounds/**
     * Set the bounds of the thumb and force a repaint that includes
     * the old thumbBounds and the new one.
     *
     * @see #getThumbBounds
     */
    protected void setThumbBounds(int x, int y, int width, int height)
    {
        /* If the thumbs bounds haven't changed, we're done.
         */
        if ((thumbRect.x == x) &&
            (thumbRect.y == y) &&
            (thumbRect.width == width) &&
            (thumbRect.height == height)) {
            return;
        }

        /* Update thumbRect, and repaint the union of x,y,w,h and
         * the old thumbRect.
         */
        int minX = Math.min(x, thumbRect.x);
        int minY = Math.min(y, thumbRect.y);
        int maxX = Math.max(x + width, thumbRect.x + thumbRect.width);
        int maxY = Math.max(y + height, thumbRect.y + thumbRect.height);

        thumbRect.setBounds(x, y, width, height);
        scrollbar.repaint(minX, minY, maxX - minX, maxY - minY);

        // Once there is API to determine the mouse location this will need
        // to be changed.
        setThumbRollover(false);
    }


    
Return the current size/location of the thumb.

Warning : the value returned by this method should not be
be modified, it's a reference to the actual rectangle, not a copy.
See Also:
setThumbBounds
Returns:
The current size/location of the thumb./**
     * Return the current size/location of the thumb.
     * <p>
     * <b>Warning </b>: the value returned by this method should not be
     * be modified, it's a reference to the actual rectangle, not a copy.
     *
     * @return The current size/location of the thumb.
     * @see #setThumbBounds
     */
    protected Rectangle getThumbBounds() {
        return thumbRect;
    }


    
Returns the current bounds of the track, i.e. the space in between
the increment and decrement buttons, less the insets.  The value
returned by this method is updated each time the scrollbar is
laid out (validated).

Warning : the value returned by this method should not be
be modified, it's a reference to the actual rectangle, not a copy.
See Also:
layoutContainer
Returns:
the current bounds of the scrollbar track/**
     * Returns the current bounds of the track, i.e. the space in between
     * the increment and decrement buttons, less the insets.  The value
     * returned by this method is updated each time the scrollbar is
     * laid out (validated).
     * <p>
     * <b>Warning </b>: the value returned by this method should not be
     * be modified, it's a reference to the actual rectangle, not a copy.
     *
     * @return the current bounds of the scrollbar track
     * @see #layoutContainer
     */
    protected Rectangle getTrackBounds() {
        return trackRect;
    }

    /*
     * Method for scrolling by a block increment.
     * Added for mouse wheel scrolling support, RFE 4202656.
     */
    static void scrollByBlock(JScrollBar scrollbar, int direction) {
        // This method is called from BasicScrollPaneUI to implement wheel
        // scrolling, and also from scrollByBlock().
            int oldValue = scrollbar.getValue();
            int blockIncrement = scrollbar.getBlockIncrement(direction);
            int delta = blockIncrement * ((direction > 0) ? +1 : -1);
            int newValue = oldValue + delta;

            // Check for overflow.
            if (delta > 0 && newValue < oldValue) {
                newValue = scrollbar.getMaximum();
            }
            else if (delta < 0 && newValue > oldValue) {
                newValue = scrollbar.getMinimum();
            }

            scrollbar.setValue(newValue);
    }

    protected void scrollByBlock(int direction)
    {
        scrollByBlock(scrollbar, direction);
            trackHighlight = direction > 0 ? INCREASE_HIGHLIGHT : DECREASE_HIGHLIGHT;
            Rectangle dirtyRect = getTrackBounds();
            scrollbar.repaint(dirtyRect.x, dirtyRect.y, dirtyRect.width, dirtyRect.height);
    }

    /*
     * Method for scrolling by a unit increment.
     * Added for mouse wheel scrolling support, RFE 4202656.
     *
     * If limitByBlock is set to true, the scrollbar will scroll at least 1
     * unit increment, but will not scroll farther than the block increment.
     * See BasicScrollPaneUI.Handler.mouseWheelMoved().
     */
    static void scrollByUnits(JScrollBar scrollbar, int direction,
                              int units, boolean limitToBlock) {
        // This method is called from BasicScrollPaneUI to implement wheel
        // scrolling, as well as from scrollByUnit().
        int delta;
        int limit = -1;

        if (limitToBlock) {
            if (direction < 0) {
                limit = scrollbar.getValue() -
                                         scrollbar.getBlockIncrement(direction);
            }
            else {
                limit = scrollbar.getValue() +
                                         scrollbar.getBlockIncrement(direction);
            }
        }

        for (int i=0; i<units; i++) {
            if (direction > 0) {
                delta = scrollbar.getUnitIncrement(direction);
            }
            else {
                delta = -scrollbar.getUnitIncrement(direction);
            }

            int oldValue = scrollbar.getValue();
            int newValue = oldValue + delta;

            // Check for overflow.
            if (delta > 0 && newValue < oldValue) {
                newValue = scrollbar.getMaximum();
            }
            else if (delta < 0 && newValue > oldValue) {
                newValue = scrollbar.getMinimum();
            }
            if (oldValue == newValue) {
                break;
            }

            if (limitToBlock && i > 0) {
                assert limit != -1;
                if ((direction < 0 && newValue < limit) ||
                    (direction > 0 && newValue > limit)) {
                    break;
                }
            }
            scrollbar.setValue(newValue);
        }
    }

    protected void scrollByUnit(int direction)  {
        scrollByUnits(scrollbar, direction, 1, false);
    }

    
Indicates whether the user can absolutely position the thumb with
a mouse gesture (usually the middle mouse button).
Returns:
true if a mouse gesture can absolutely position the thumb
Since:
1.5/**
     * Indicates whether the user can absolutely position the thumb with
     * a mouse gesture (usually the middle mouse button).
     *
     * @return true if a mouse gesture can absolutely position the thumb
     * @since 1.5
     */
    public boolean getSupportsAbsolutePositioning() {
        return supportsAbsolutePositioning;
    }

    
A listener to listen for model changes.
/**
     * A listener to listen for model changes.
     *
     */
    protected class ModelListener implements ChangeListener {
        public void stateChanged(ChangeEvent e) {
            if (!useCachedValue) {
                scrollBarValue = scrollbar.getValue();
            }
            layoutContainer(scrollbar);
            useCachedValue = false;
        }
    }


    
Track mouse drags.
/**
     * Track mouse drags.
     */
    protected class TrackListener
        extends MouseAdapter implements MouseMotionListener
    {
        protected transient int offset;
        protected transient int currentMouseX, currentMouseY;
        private transient int direction = +1;

        public void mouseReleased(MouseEvent e)
        {
            if (isDragging) {
                updateThumbState(e.getX(), e.getY());
            }
            if (SwingUtilities.isRightMouseButton(e) ||
                (!getSupportsAbsolutePositioning() &&
                 SwingUtilities.isMiddleMouseButton(e)))
                return;
            if(!scrollbar.isEnabled())
                return;

            Rectangle r = getTrackBounds();
            scrollbar.repaint(r.x, r.y, r.width, r.height);

            trackHighlight = NO_HIGHLIGHT;
            isDragging = false;
            offset = 0;
            scrollTimer.stop();
            useCachedValue = true;
            scrollbar.setValueIsAdjusting(false);
        }


        
If the mouse is pressed above the "thumb" component
then reduce the scrollbars value by one page ("page up"),
otherwise increase it by one page.  If there is no
thumb then page up if the mouse is in the upper half
of the track.
/**
         * If the mouse is pressed above the "thumb" component
         * then reduce the scrollbars value by one page ("page up"),
         * otherwise increase it by one page.  If there is no
         * thumb then page up if the mouse is in the upper half
         * of the track.
         */
        public void mousePressed(MouseEvent e)
        {
            if (SwingUtilities.isRightMouseButton(e) ||
                (!getSupportsAbsolutePositioning() &&
                 SwingUtilities.isMiddleMouseButton(e)))
                return;
            if(!scrollbar.isEnabled())
                return;

            if (!scrollbar.hasFocus() && scrollbar.isRequestFocusEnabled()) {
                scrollbar.requestFocus();
            }

            useCachedValue = true;
            scrollbar.setValueIsAdjusting(true);

            currentMouseX = e.getX();
            currentMouseY = e.getY();

            // Clicked in the Thumb area?
            if(getThumbBounds().contains(currentMouseX, currentMouseY)) {
                switch (scrollbar.getOrientation()) {
                case JScrollBar.VERTICAL:
                    offset = currentMouseY - getThumbBounds().y;
                    break;
                case JScrollBar.HORIZONTAL:
                    offset = currentMouseX - getThumbBounds().x;
                    break;
                }
                isDragging = true;
                return;
            }
            else if (getSupportsAbsolutePositioning() &&
                     SwingUtilities.isMiddleMouseButton(e)) {
                switch (scrollbar.getOrientation()) {
                case JScrollBar.VERTICAL:
                    offset = getThumbBounds().height / 2;
                    break;
                case JScrollBar.HORIZONTAL:
                    offset = getThumbBounds().width / 2;
                    break;
                }
                isDragging = true;
                setValueFrom(e);
                return;
            }
            isDragging = false;

            Dimension sbSize = scrollbar.getSize();
            direction = +1;

            switch (scrollbar.getOrientation()) {
            case JScrollBar.VERTICAL:
                if (getThumbBounds().isEmpty()) {
                    int scrollbarCenter = sbSize.height / 2;
                    direction = (currentMouseY < scrollbarCenter) ? -1 : +1;
                } else {
                    int thumbY = getThumbBounds().y;
                    direction = (currentMouseY < thumbY) ? -1 : +1;
                }
                break;
            case JScrollBar.HORIZONTAL:
                if (getThumbBounds().isEmpty()) {
                    int scrollbarCenter = sbSize.width / 2;
                    direction = (currentMouseX < scrollbarCenter) ? -1 : +1;
                } else {
                    int thumbX = getThumbBounds().x;
                    direction = (currentMouseX < thumbX) ? -1 : +1;
                }
                if (!scrollbar.getComponentOrientation().isLeftToRight()) {
                    direction = -direction;
                }
                break;
            }
            scrollByBlock(direction);

            scrollTimer.stop();
            scrollListener.setDirection(direction);
            scrollListener.setScrollByBlock(true);
            startScrollTimerIfNecessary();
        }


        
Set the models value to the position of the thumb's top of Vertical
scrollbar, or the left/right of Horizontal scrollbar in
left-to-right/right-to-left scrollbar relative to the origin of the
track.
/**
         * Set the models value to the position of the thumb's top of Vertical
         * scrollbar, or the left/right of Horizontal scrollbar in
         * left-to-right/right-to-left scrollbar relative to the origin of the
         * track.
         */
        public void mouseDragged(MouseEvent e) {
            if (SwingUtilities.isRightMouseButton(e) ||
                (!getSupportsAbsolutePositioning() &&
                 SwingUtilities.isMiddleMouseButton(e)))
                return;
            if(!scrollbar.isEnabled() || getThumbBounds().isEmpty()) {
                return;
            }
            if (isDragging) {
                setValueFrom(e);
            } else {
                currentMouseX = e.getX();
                currentMouseY = e.getY();
                updateThumbState(currentMouseX, currentMouseY);
                startScrollTimerIfNecessary();
            }
        }

        private void setValueFrom(MouseEvent e) {
            boolean active = isThumbRollover();
            BoundedRangeModel model = scrollbar.getModel();
            Rectangle thumbR = getThumbBounds();
            float trackLength;
            int thumbMin, thumbMax, thumbPos;

            if (scrollbar.getOrientation() == JScrollBar.VERTICAL) {
                thumbMin = trackRect.y;
                thumbMax = trackRect.y + trackRect.height - thumbR.height;
                thumbPos = Math.min(thumbMax, Math.max(thumbMin, (e.getY() - offset)));
                setThumbBounds(thumbR.x, thumbPos, thumbR.width, thumbR.height);
                trackLength = getTrackBounds().height;
            }
            else {
                thumbMin = trackRect.x;
                thumbMax = trackRect.x + trackRect.width - thumbR.width;
                thumbPos = Math.min(thumbMax, Math.max(thumbMin, (e.getX() - offset)));
                setThumbBounds(thumbPos, thumbR.y, thumbR.width, thumbR.height);
                trackLength = getTrackBounds().width;
            }

            /* Set the scrollbars value.  If the thumb has reached the end of
             * the scrollbar, then just set the value to its maximum.  Otherwise
             * compute the value as accurately as possible.
             */
            if (thumbPos == thumbMax) {
                if (scrollbar.getOrientation() == JScrollBar.VERTICAL ||
                    scrollbar.getComponentOrientation().isLeftToRight()) {
                    scrollbar.setValue(model.getMaximum() - model.getExtent());
                } else {
                    scrollbar.setValue(model.getMinimum());
                }
            }
            else {
                float valueMax = model.getMaximum() - model.getExtent();
                float valueRange = valueMax - model.getMinimum();
                float thumbValue = thumbPos - thumbMin;
                float thumbRange = thumbMax - thumbMin;
                int value;
                if (scrollbar.getOrientation() == JScrollBar.VERTICAL ||
                    scrollbar.getComponentOrientation().isLeftToRight()) {
                    value = (int)(0.5 + ((thumbValue / thumbRange) * valueRange));
                } else {
                    value = (int)(0.5 + (((thumbMax - thumbPos) / thumbRange) * valueRange));
                }

                useCachedValue = true;
                scrollBarValue = value + model.getMinimum();
                scrollbar.setValue(adjustValueIfNecessary(scrollBarValue));
            }
            setThumbRollover(active);
        }

        private int adjustValueIfNecessary(int value) {
            if (scrollbar.getParent() instanceof JScrollPane) {
                JScrollPane scrollpane = (JScrollPane)scrollbar.getParent();
                JViewport viewport = scrollpane.getViewport();
                Component view = viewport.getView();
                if (view instanceof JList) {
                    JList list = (JList)view;
                    if (DefaultLookup.getBoolean(list, list.getUI(),
                                                 "List.lockToPositionOnScroll", false)) {
                        int adjustedValue = value;
                        int mode = list.getLayoutOrientation();
                        int orientation = scrollbar.getOrientation();
                        if (orientation == JScrollBar.VERTICAL && mode == JList.VERTICAL) {
                            int index = list.locationToIndex(new Point(0, value));
                            Rectangle rect = list.getCellBounds(index, index);
                            if (rect != null) {
                                adjustedValue = rect.y;
                            }
                        }
                        if (orientation == JScrollBar.HORIZONTAL &&
                            (mode == JList.VERTICAL_WRAP || mode == JList.HORIZONTAL_WRAP)) {
                            if (scrollpane.getComponentOrientation().isLeftToRight()) {
                                int index = list.locationToIndex(new Point(value, 0));
                                Rectangle rect = list.getCellBounds(index, index);
                                if (rect != null) {
                                    adjustedValue = rect.x;
                                }
                            }
                            else {
                                Point loc = new Point(value, 0);
                                int extent = viewport.getExtentSize().width;
                                loc.x += extent - 1;
                                int index = list.locationToIndex(loc);
                                Rectangle rect = list.getCellBounds(index, index);
                                if (rect != null) {
                                    adjustedValue = rect.x + rect.width - extent;
                                }
                            }
                        }
                        value = adjustedValue;

                    }
                }
            }
            return value;
        }

        private void startScrollTimerIfNecessary() {
            if (scrollTimer.isRunning()) {
                return;
            }

            Rectangle tb = getThumbBounds();

            switch (scrollbar.getOrientation()) {
            case JScrollBar.VERTICAL:
                if (direction > 0) {
                    if (tb.y + tb.height < trackListener.currentMouseY) {
                        scrollTimer.start();
                    }
                } else if (tb.y > trackListener.currentMouseY) {
                    scrollTimer.start();
                }
                break;
            case JScrollBar.HORIZONTAL:
                if ((direction > 0 && isMouseAfterThumb())
                        || (direction < 0 && isMouseBeforeThumb())) {

                    scrollTimer.start();
                }
                break;
            }
        }

        public void mouseMoved(MouseEvent e) {
            if (!isDragging) {
                updateThumbState(e.getX(), e.getY());
            }
        }

        
Invoked when the mouse exits the scrollbar.
Params:
e – MouseEvent further describing the event
Since:
1.5/**
         * Invoked when the mouse exits the scrollbar.
         *
         * @param e MouseEvent further describing the event
         * @since 1.5
         */
        public void mouseExited(MouseEvent e) {
            if (!isDragging) {
                setThumbRollover(false);
            }
        }
    }


    
Listener for cursor keys.
/**
     * Listener for cursor keys.
     */
    protected class ArrowButtonListener extends MouseAdapter
    {
        // Because we are handling both mousePressed and Actions
        // we need to make sure we don't fire under both conditions.
        // (keyfocus on scrollbars causes action without mousePress
        boolean handledEvent;

        public void mousePressed(MouseEvent e)          {
            if(!scrollbar.isEnabled()) { return; }
            // not an unmodified left mouse button
            //if(e.getModifiers() != InputEvent.BUTTON1_MASK) {return; }
            if( ! SwingUtilities.isLeftMouseButton(e)) { return; }

            int direction = (e.getSource() == incrButton) ? 1 : -1;

            scrollByUnit(direction);
            scrollTimer.stop();
            scrollListener.setDirection(direction);
            scrollListener.setScrollByBlock(false);
            scrollTimer.start();

            handledEvent = true;
            if (!scrollbar.hasFocus() && scrollbar.isRequestFocusEnabled()) {
                scrollbar.requestFocus();
            }
        }

        public void mouseReleased(MouseEvent e)         {
            scrollTimer.stop();
            handledEvent = false;
            scrollbar.setValueIsAdjusting(false);
        }
    }


    
Listener for scrolling events initiated in the
ScrollPane.
/**
     * Listener for scrolling events initiated in the
     * <code>ScrollPane</code>.
     */
    protected class ScrollListener implements ActionListener
    {
        int direction = +1;
        boolean useBlockIncrement;

        public ScrollListener() {
            direction = +1;
            useBlockIncrement = false;
        }

        public ScrollListener(int dir, boolean block)   {
            direction = dir;
            useBlockIncrement = block;
        }

        public void setDirection(int direction) { this.direction = direction; }
        public void setScrollByBlock(boolean block) { this.useBlockIncrement = block; }

        public void actionPerformed(ActionEvent e) {
            if(useBlockIncrement)       {
                scrollByBlock(direction);
                // Stop scrolling if the thumb catches up with the mouse
                if(scrollbar.getOrientation() == JScrollBar.VERTICAL)   {
                    if(direction > 0)   {
                        if(getThumbBounds().y + getThumbBounds().height
                                >= trackListener.currentMouseY)
                                    ((Timer)e.getSource()).stop();
                    } else if(getThumbBounds().y <= trackListener.currentMouseY)        {
                        ((Timer)e.getSource()).stop();
                    }
                } else {
                    if ((direction > 0 && !isMouseAfterThumb())
                           || (direction < 0 && !isMouseBeforeThumb())) {

                       ((Timer)e.getSource()).stop();
                    }
                }
            } else {
                scrollByUnit(direction);
            }

            if(direction > 0
                && scrollbar.getValue()+scrollbar.getVisibleAmount()
                        >= scrollbar.getMaximum())
                ((Timer)e.getSource()).stop();
            else if(direction < 0
                && scrollbar.getValue() <= scrollbar.getMinimum())
                ((Timer)e.getSource()).stop();
        }
    }

    private boolean isMouseLeftOfThumb() {
        return trackListener.currentMouseX < getThumbBounds().x;
    }

    private boolean isMouseRightOfThumb() {
        Rectangle tb = getThumbBounds();
        return trackListener.currentMouseX > tb.x + tb.width;
    }

    private boolean isMouseBeforeThumb() {
        return scrollbar.getComponentOrientation().isLeftToRight()
            ? isMouseLeftOfThumb()
            : isMouseRightOfThumb();
    }

    private boolean isMouseAfterThumb() {
        return scrollbar.getComponentOrientation().isLeftToRight()
            ? isMouseRightOfThumb()
            : isMouseLeftOfThumb();
    }

    private void updateButtonDirections() {
        int orient = scrollbar.getOrientation();
        if (scrollbar.getComponentOrientation().isLeftToRight()) {
            if (incrButton instanceof BasicArrowButton) {
                ((BasicArrowButton)incrButton).setDirection(
                        orient == HORIZONTAL? EAST : SOUTH);
            }
            if (decrButton instanceof BasicArrowButton) {
                ((BasicArrowButton)decrButton).setDirection(
                        orient == HORIZONTAL? WEST : NORTH);
            }
        }
        else {
            if (incrButton instanceof BasicArrowButton) {
                ((BasicArrowButton)incrButton).setDirection(
                        orient == HORIZONTAL? WEST : SOUTH);
            }
            if (decrButton instanceof BasicArrowButton) {
                ((BasicArrowButton)decrButton).setDirection(
                        orient == HORIZONTAL ? EAST : NORTH);
            }
        }
    }

    public class PropertyChangeHandler implements PropertyChangeListener
    {
        // NOTE: This class exists only for backward compatability. All
        // its functionality has been moved into Handler. If you need to add
        // new functionality add it to the Handler, but make sure this
        // class calls into the Handler.

        public void propertyChange(PropertyChangeEvent e) {
            getHandler().propertyChange(e);
        }
    }


    
Used for scrolling the scrollbar.
/**
     * Used for scrolling the scrollbar.
     */
    private static class Actions extends UIAction {
        private static final String POSITIVE_UNIT_INCREMENT =
                                    "positiveUnitIncrement";
        private static final String POSITIVE_BLOCK_INCREMENT =
                                    "positiveBlockIncrement";
        private static final String NEGATIVE_UNIT_INCREMENT =
                                    "negativeUnitIncrement";
        private static final String NEGATIVE_BLOCK_INCREMENT =
                                    "negativeBlockIncrement";
        private static final String MIN_SCROLL = "minScroll";
        private static final String MAX_SCROLL = "maxScroll";

        Actions(String name) {
            super(name);
        }

        public void actionPerformed(ActionEvent e) {
            JScrollBar scrollBar = (JScrollBar)e.getSource();
            String key = getName();
            if (key == POSITIVE_UNIT_INCREMENT) {
                scroll(scrollBar, POSITIVE_SCROLL, false);
            }
            else if (key == POSITIVE_BLOCK_INCREMENT) {
                scroll(scrollBar, POSITIVE_SCROLL, true);
            }
            else if (key == NEGATIVE_UNIT_INCREMENT) {
                scroll(scrollBar, NEGATIVE_SCROLL, false);
            }
            else if (key == NEGATIVE_BLOCK_INCREMENT) {
                scroll(scrollBar, NEGATIVE_SCROLL, true);
            }
            else if (key == MIN_SCROLL) {
                scroll(scrollBar, BasicScrollBarUI.MIN_SCROLL, true);
            }
            else if (key == MAX_SCROLL) {
                scroll(scrollBar, BasicScrollBarUI.MAX_SCROLL, true);
            }
        }
        private void scroll(JScrollBar scrollBar, int dir, boolean block) {

            if (dir == NEGATIVE_SCROLL || dir == POSITIVE_SCROLL) {
                int amount;
                // Don't use the BasicScrollBarUI.scrollByXXX methods as we
                // don't want to use an invokeLater to reset the trackHighlight
                // via an invokeLater
                if (block) {
                    if (dir == NEGATIVE_SCROLL) {
                        amount = -1 * scrollBar.getBlockIncrement(-1);
                    }
                    else {
                        amount = scrollBar.getBlockIncrement(1);
                    }
                }
                else {
                    if (dir == NEGATIVE_SCROLL) {
                        amount = -1 * scrollBar.getUnitIncrement(-1);
                    }
                    else {
                        amount = scrollBar.getUnitIncrement(1);
                    }
                }
                scrollBar.setValue(scrollBar.getValue() + amount);
            }
            else if (dir == BasicScrollBarUI.MIN_SCROLL) {
                scrollBar.setValue(scrollBar.getMinimum());
            }
            else if (dir == BasicScrollBarUI.MAX_SCROLL) {
                scrollBar.setValue(scrollBar.getMaximum());
            }
        }
    }


    //
    // EventHandler
    //
    private class Handler implements FocusListener, PropertyChangeListener {
        //
        // FocusListener
        //
        public void focusGained(FocusEvent e) {
            scrollbar.repaint();
        }

        public void focusLost(FocusEvent e) {
            scrollbar.repaint();
        }


        //
        // PropertyChangeListener
        //
        public void propertyChange(PropertyChangeEvent e) {
            String propertyName = e.getPropertyName();

            if ("model" == propertyName) {
                BoundedRangeModel oldModel = (BoundedRangeModel)e.getOldValue();
                BoundedRangeModel newModel = (BoundedRangeModel)e.getNewValue();
                oldModel.removeChangeListener(modelListener);
                newModel.addChangeListener(modelListener);
                scrollbar.repaint();
                scrollbar.revalidate();
            } else if ("orientation" == propertyName) {
                updateButtonDirections();
            } else if ("componentOrientation" == propertyName) {
                updateButtonDirections();
                InputMap inputMap = getInputMap(JComponent.WHEN_FOCUSED);
                SwingUtilities.replaceUIInputMap(scrollbar, JComponent.WHEN_FOCUSED, inputMap);
            }
        }
    }
}