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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 sun.swing.DefaultLookup;

import sun.swing.UIAction;

import javax.swing.*;

import javax.swing.event.*;

import javax.swing.border.*;

import javax.swing.plaf.*;

import java.beans.PropertyChangeListener;

import java.beans.PropertyChangeEvent;

import java.awt.Component;

import java.awt.Rectangle;

import java.awt.Dimension;

import java.awt.Point;

import java.awt.Insets;

import java.awt.Graphics;

import java.awt.event.*;

/**

 * A default L&F implementation of ScrollPaneUI.

 *

 * @author Hans Muller

 */

public class BasicScrollPaneUI

    extends ScrollPaneUI implements ScrollPaneConstants

{

    /**

     * The instance of {@code JScrollPane}.

     */

    protected JScrollPane scrollpane;

    /**

     * {@code ChangeListener} installed on the vertical scrollbar.

     */

    protected ChangeListener vsbChangeListener;

    /**

     * {@code ChangeListener} installed on the horizontal scrollbar.

     */

    protected ChangeListener hsbChangeListener;

    /**

     * {@code ChangeListener} installed on the viewport.

     */

    protected ChangeListener viewportChangeListener;

    /**

     * {@code PropertyChangeListener} installed on the scroll pane.

     */

    protected PropertyChangeListener spPropertyChangeListener;

    private MouseWheelListener mouseScrollListener;

    private int oldExtent = Integer.MIN_VALUE;

    /**

     * {@code PropertyChangeListener} installed on the vertical scrollbar.

     */

    private PropertyChangeListener vsbPropertyChangeListener;

    /**

     * {@code PropertyChangeListener} installed on the horizontal scrollbar.

     */

    private PropertyChangeListener hsbPropertyChangeListener;

    private Handler handler;

    /**

     * State flag that shows whether setValue() was called from a user program

     * before the value of "extent" was set in right-to-left component

     * orientation.

     */

    private boolean setValueCalled = false;

    /**

     * Returns a new instance of {@code BasicScrollPaneUI}.

     *

     * @param x a component.

     * @return a new instance of {@code BasicScrollPaneUI}

     */

    public static ComponentUI createUI(JComponent x) {

        return new BasicScrollPaneUI();

    }

    static void loadActionMap(LazyActionMap map) {

        map.put(new Actions(Actions.SCROLL_UP));

        map.put(new Actions(Actions.SCROLL_DOWN));

        map.put(new Actions(Actions.SCROLL_HOME));

        map.put(new Actions(Actions.SCROLL_END));

        map.put(new Actions(Actions.UNIT_SCROLL_UP));

        map.put(new Actions(Actions.UNIT_SCROLL_DOWN));

        map.put(new Actions(Actions.SCROLL_LEFT));

        map.put(new Actions(Actions.SCROLL_RIGHT));

        map.put(new Actions(Actions.UNIT_SCROLL_RIGHT));

        map.put(new Actions(Actions.UNIT_SCROLL_LEFT));

    }

    public void paint(Graphics g, JComponent c) {

        Border vpBorder = scrollpane.getViewportBorder();

        if (vpBorder != null) {

            Rectangle r = scrollpane.getViewportBorderBounds();

            vpBorder.paintBorder(scrollpane, g, r.x, r.y, r.width, r.height);

        }

    }

    /**

     * @return new Dimension(Short.MAX_VALUE, Short.MAX_VALUE)

     */

    public Dimension getMaximumSize(JComponent c) {

        return new Dimension(Short.MAX_VALUE, Short.MAX_VALUE);

    }

    /**

     * Installs default properties.

     *

     * @param scrollpane an instance of {@code JScrollPane}

     */

    protected void installDefaults(JScrollPane scrollpane)

    {

        LookAndFeel.installBorder(scrollpane, "ScrollPane.border");

        LookAndFeel.installColorsAndFont(scrollpane,

            "ScrollPane.background",

            "ScrollPane.foreground",

            "ScrollPane.font");

        Border vpBorder = scrollpane.getViewportBorder();

        if ((vpBorder == null) ||( vpBorder instanceof UIResource)) {

            vpBorder = UIManager.getBorder("ScrollPane.viewportBorder");

            scrollpane.setViewportBorder(vpBorder);

        }

        LookAndFeel.installProperty(scrollpane, "opaque", Boolean.TRUE);

    }

    /**

     * Registers listeners.

     *

     * @param c an instance of {@code JScrollPane}

     */

    protected void installListeners(JScrollPane c)

    {

        vsbChangeListener = createVSBChangeListener();

        vsbPropertyChangeListener = createVSBPropertyChangeListener();

        hsbChangeListener = createHSBChangeListener();

        hsbPropertyChangeListener = createHSBPropertyChangeListener();

        viewportChangeListener = createViewportChangeListener();

        spPropertyChangeListener = createPropertyChangeListener();

        JViewport viewport = scrollpane.getViewport();

        JScrollBar vsb = scrollpane.getVerticalScrollBar();

        JScrollBar hsb = scrollpane.getHorizontalScrollBar();

        if (viewport != null) {

            viewport.addChangeListener(viewportChangeListener);

        }

        if (vsb != null) {

            vsb.getModel().addChangeListener(vsbChangeListener);

            vsb.addPropertyChangeListener(vsbPropertyChangeListener);

        }

        if (hsb != null) {

            hsb.getModel().addChangeListener(hsbChangeListener);

            hsb.addPropertyChangeListener(hsbPropertyChangeListener);

        }

        scrollpane.addPropertyChangeListener(spPropertyChangeListener);

    mouseScrollListener = createMouseWheelListener();

    scrollpane.addMouseWheelListener(mouseScrollListener);

    }

    /**

     * Registers keyboard actions.

     *

     * @param c an instance of {@code JScrollPane}

     */

    protected void installKeyboardActions(JScrollPane c) {

        InputMap inputMap = getInputMap(JComponent.

                                  WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);

        SwingUtilities.replaceUIInputMap(c, JComponent.

                               WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, inputMap);

        LazyActionMap.installLazyActionMap(c, BasicScrollPaneUI.class,

                                           "ScrollPane.actionMap");

    }

    InputMap getInputMap(int condition) {

        if (condition == JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT) {

            InputMap keyMap = (InputMap)DefaultLookup.get(scrollpane, this,

                                        "ScrollPane.ancestorInputMap");

            InputMap rtlKeyMap;

            if (scrollpane.getComponentOrientation().isLeftToRight() ||

                    ((rtlKeyMap = (InputMap)DefaultLookup.get(scrollpane, this,

                    "ScrollPane.ancestorInputMap.RightToLeft")) == null)) {

                return keyMap;

            } else {

                rtlKeyMap.setParent(keyMap);

                return rtlKeyMap;

            }

        }

        return null;

    }

    public void installUI(JComponent x) {

        scrollpane = (JScrollPane)x;

        installDefaults(scrollpane);

        installListeners(scrollpane);

        installKeyboardActions(scrollpane);

    }

    /**

     * Uninstalls default properties.

     *

     * @param c an instance of {@code JScrollPane}

     */

    protected void uninstallDefaults(JScrollPane c) {

        LookAndFeel.uninstallBorder(scrollpane);

        if (scrollpane.getViewportBorder() instanceof UIResource) {

            scrollpane.setViewportBorder(null);

        }

    }

    /**

     * Unregisters listeners.

     *

     * @param c a component

     */

    protected void uninstallListeners(JComponent c) {

        JViewport viewport = scrollpane.getViewport();

        JScrollBar vsb = scrollpane.getVerticalScrollBar();

        JScrollBar hsb = scrollpane.getHorizontalScrollBar();

        if (viewport != null) {

            viewport.removeChangeListener(viewportChangeListener);

        }

        if (vsb != null) {

            vsb.getModel().removeChangeListener(vsbChangeListener);

            vsb.removePropertyChangeListener(vsbPropertyChangeListener);

        }

        if (hsb != null) {

            hsb.getModel().removeChangeListener(hsbChangeListener);

            hsb.removePropertyChangeListener(hsbPropertyChangeListener);

        }

        scrollpane.removePropertyChangeListener(spPropertyChangeListener);

    if (mouseScrollListener != null) {

        scrollpane.removeMouseWheelListener(mouseScrollListener);

    }

        vsbChangeListener = null;

        hsbChangeListener = null;

        viewportChangeListener = null;

        spPropertyChangeListener = null;

        mouseScrollListener = null;

        handler = null;

    }

    /**

     * Unregisters keyboard actions.

     *

     * @param c an instance of {@code JScrollPane}

     */

    protected void uninstallKeyboardActions(JScrollPane c) {

        SwingUtilities.replaceUIActionMap(c, null);

        SwingUtilities.replaceUIInputMap(c, JComponent.

                           WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, null);

    }

    public void uninstallUI(JComponent c) {

        uninstallDefaults(scrollpane);

        uninstallListeners(scrollpane);

        uninstallKeyboardActions(scrollpane);

        scrollpane = null;

    }

    private Handler getHandler() {

        if (handler == null) {

            handler = new Handler();

        }

        return handler;

    }

    /**

     * Synchronizes the {@code JScrollPane} with {@code Viewport}.

     */

    protected void syncScrollPaneWithViewport()

    {

        JViewport viewport = scrollpane.getViewport();

        JScrollBar vsb = scrollpane.getVerticalScrollBar();

        JScrollBar hsb = scrollpane.getHorizontalScrollBar();

        JViewport rowHead = scrollpane.getRowHeader();

        JViewport colHead = scrollpane.getColumnHeader();

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

        if (viewport != null) {

            Dimension extentSize = viewport.getExtentSize();

            Dimension viewSize = viewport.getViewSize();

            Point viewPosition = viewport.getViewPosition();

            if (vsb != null) {

                int extent = extentSize.height;

                int max = viewSize.height;

                int value = Math.max(0, Math.min(viewPosition.y, max - extent));

                vsb.setValues(value, extent, 0, max);

            }

            if (hsb != null) {

                int extent = extentSize.width;

                int max = viewSize.width;

                int value;

                if (ltr) {

                    value = Math.max(0, Math.min(viewPosition.x, max - extent));

                } else {

                    int currentValue = hsb.getValue();

                    /* Use a particular formula to calculate "value"

                     * until effective x coordinate is calculated.

                     */

                    if (setValueCalled && ((max - currentValue) == viewPosition.x)) {

                        value = Math.max(0, Math.min(max - extent, currentValue));

                        /* After "extent" is set, turn setValueCalled flag off.

                         */

                        if (extent != 0) {

                            setValueCalled = false;

                        }

                    } else {

                        if (extent > max) {

                            viewPosition.x = max - extent;

                            viewport.setViewPosition(viewPosition);

                            value = 0;

                        } else {

                           /* The following line can't handle a small value of

                            * viewPosition.x like Integer.MIN_VALUE correctly

                            * because (max - extent - viewPositoiin.x) causes

                            * an overflow. As a result, value becomes zero.

                            * (e.g. setViewPosition(Integer.MAX_VALUE, ...)

                            *       in a user program causes a overflow.

                            *       Its expected value is (max - extent).)

                            * However, this seems a trivial bug and adding a

                            * fix makes this often-called method slow, so I'll

                            * leave it until someone claims.

                            */

                            value = Math.max(0, Math.min(max - extent, max - extent - viewPosition.x));

                            if (oldExtent > extent) {

                                value -= oldExtent - extent;

                            }

                        }

                    }

                }

                oldExtent = extent;

                hsb.setValues(value, extent, 0, max);

            }

            if (rowHead != null) {

                Point p = rowHead.getViewPosition();

                p.y = viewport.getViewPosition().y;

                p.x = 0;

                rowHead.setViewPosition(p);

            }

            if (colHead != null) {

                Point p = colHead.getViewPosition();

                if (ltr) {

                    p.x = viewport.getViewPosition().x;

                } else {

                    p.x = Math.max(0, viewport.getViewPosition().x);

                }

                p.y = 0;

                colHead.setViewPosition(p);

            }

        }

    }

    /**

     * Returns the baseline.

     *

     * @throws NullPointerException {@inheritDoc}

     * @throws IllegalArgumentException {@inheritDoc}

     * @see javax.swing.JComponent#getBaseline(int, int)

     * @since 1.6

     */

    public int getBaseline(JComponent c, int width, int height) {

        if (c == null) {

            throw new NullPointerException("Component must be non-null");

        }

        if (width < 0 || height < 0) {

            throw new IllegalArgumentException("Width and height must be >= 0");

        }

        JViewport viewport = scrollpane.getViewport();

        Insets spInsets = scrollpane.getInsets();

        int y = spInsets.top;

        height = height - spInsets.top - spInsets.bottom;

        width = width - spInsets.left - spInsets.right;

        JViewport columnHeader = scrollpane.getColumnHeader();

        if (columnHeader != null && columnHeader.isVisible()) {

            Component header = columnHeader.getView();

            if (header != null && header.isVisible()) {

                // Header is always given it's preferred size.

                Dimension headerPref = header.getPreferredSize();

                int baseline = header.getBaseline(headerPref.width,

                                                  headerPref.height);

                if (baseline >= 0) {

                    return y + baseline;

                }

            }

            Dimension columnPref = columnHeader.getPreferredSize();

            height -= columnPref.height;

            y += columnPref.height;

        }

        Component view = (viewport == null) ? null : viewport.getView();

        if (view != null && view.isVisible() &&

                view.getBaselineResizeBehavior() ==

                Component.BaselineResizeBehavior.CONSTANT_ASCENT) {

            Border viewportBorder = scrollpane.getViewportBorder();

            if (viewportBorder != null) {

                Insets vpbInsets = viewportBorder.getBorderInsets(scrollpane);

                y += vpbInsets.top;

                height = height - vpbInsets.top - vpbInsets.bottom;

                width = width - vpbInsets.left - vpbInsets.right;

            }

            if (view.getWidth() > 0 && view.getHeight() > 0) {

                Dimension min = view.getMinimumSize();

                width = Math.max(min.width, view.getWidth());

                height = Math.max(min.height, view.getHeight());

            }

            if (width > 0 && height > 0) {

                int baseline = view.getBaseline(width, height);

                if (baseline > 0) {

                    return y + baseline;

                }

            }

        }

        return -1;

    }

    /**

     * Returns an enum indicating how the baseline of the component

     * changes as the size changes.

     *

     * @throws NullPointerException {@inheritDoc}

     * @see javax.swing.JComponent#getBaseline(int, int)

     * @since 1.6

     */

    public Component.BaselineResizeBehavior getBaselineResizeBehavior(

            JComponent c) {

        super.getBaselineResizeBehavior(c);

        // Baseline is either from the header, in which case it's always

        // the same size and therefor can be created as CONSTANT_ASCENT.

        // If the header doesn't have a baseline than the baseline will only

        // be valid if it's BaselineResizeBehavior is

        // CONSTANT_ASCENT, so, return CONSTANT_ASCENT.

        return Component.BaselineResizeBehavior.CONSTANT_ASCENT;

    }

    /**

     * Listener for viewport events.

     */

    public class ViewportChangeHandler implements ChangeListener

    {

        // NOTE: This class exists only for backward compatibility. 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 stateChanged(ChangeEvent e) {

            getHandler().stateChanged(e);

        }

    }

    /**

     * Returns an instance of viewport {@code ChangeListener}.

     *

     * @return an instance of viewport {@code ChangeListener}

     */

    protected ChangeListener createViewportChangeListener() {

        return getHandler();

    }

    /**

     * Horizontal scrollbar listener.