/* JScrollPane.java --    Copyright (C) 2002, 2004, 2005  Free Software Foundation, Inc.This file is part of GNU Classpath.GNU Classpath is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 2, or (at your option)any later version.GNU Classpath is distributed in the hope that it will be useful, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNUGeneral Public License for more details.You should have received a copy of the GNU General Public Licensealong with GNU Classpath; see the file COPYING.  If not, write to theFree Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA02110-1301 USA.Linking this library statically or dynamically with other modules ismaking a combined work based on this library.  Thus, the terms andconditions of the GNU General Public License cover the wholecombination.As a special exception, the copyright holders of this library give youpermission to link this library with independent modules to produce anexecutable, regardless of the license terms of these independentmodules, and to copy and distribute the resulting executable underterms of your choice, provided that you also meet, for each linkedindependent module, the terms and conditions of the license of thatmodule.  An independent module is a module which is not derived fromor based on this library.  If you modify this library, you may extendthis exception to your version of the library, but you are notobligated to do so.  If you do not wish to do so, delete thisexception statement from your version. */package javax.swing;import java.awt.Component;import java.awt.ComponentOrientation;import java.awt.Insets;import java.awt.LayoutManager;import java.awt.Rectangle;import java.beans.PropertyChangeEvent;import java.beans.PropertyChangeListener;import javax.accessibility.Accessible;import javax.accessibility.AccessibleContext;import javax.swing.border.Border;import javax.swing.event.ChangeEvent;import javax.swing.event.ChangeListener;import javax.swing.plaf.ScrollPaneUI;import javax.swing.plaf.UIResource;/** * A component that embeds another component and enables it to be scrolled * both in horizontal and vertical direction. * * <table> * <tr><th>Property                    </th><th>Stored in       </th><th>Bound?</th></tr> * <tr><td>columnHeader                </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>columnHeaderView            </td><td>columnHeader    </td><td>no    </td></tr> * <tr><td>componentOrientation        </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>horizontalScrollBar         </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>horizontalScrollBarPolicy   </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>layout                      </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>rowHeader                   </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>rowHeaderView               </td><td>rowHeader       </td><td>no    </td></tr> * <tr><td>validateRoot                </td><td>scrollPane      </td><td>no    </td></tr> * <tr><td>verticalScrollBar           </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>verticalScrollBarPolicy     </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>viewport                    </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>viewportBorder              </td><td>scrollPane      </td><td>yes   </td></tr> * <tr><td>viewportBorderBounds        </td><td>scrollPane      </td><td>no    </td></tr> * <tr><td>viewportView                </td><td>viewport        </td><td>no    </td></tr> * <tr><td>wheelScrollingEnabled       </td><td>scrollPane      </td><td>yes   </td></tr> * </table> */public class JScrollPane extends JComponent  implements Accessible, ScrollPaneConstants{  /**   * Provides accessibility support for the <code>JScrollPane</code>.   *   * @author Roman Kennke (kennke@aicas.com)   */  protected class AccessibleJScrollPane extends AccessibleJComponent    implements ChangeListener, PropertyChangeListener  {    /**     * The viewport of the underlying scrollpane.     */    protected JViewport viewPort;    /**     * Creates a new <code>AccessibleJScrollPane</code> object. This     * initializes the <code>viewport</code> field with the current viewport     * from the scrollpane associated with this     * <code>AccessibleJScrollPane</code>.     */    public AccessibleJScrollPane()    {      viewPort = getViewport();      viewPort.addChangeListener(this);      viewPort.addPropertyChangeListener(this);    }    /**     * Receives notification when the state of the viewport changes.     *     * @param event the change event     */    public void stateChanged(ChangeEvent event)    {      // TODO: Figure out what should be done here, if anything.    }    /**     * Receives notification if any of the viewport's bound properties changes.     *     * @param e the propery change event     */    public void propertyChange(PropertyChangeEvent e)    {      // TODO: Figure out what should be done here, if anything.    }    /**     * Resets the <code>viewPort</code> field when the scrollpane's viewport     * changes. This method is called by     * {@link JScrollPane#setViewport(JViewport)} in order to update the     * <code>viewPort</code> field and set up the listeners on this viewport     * correctly.     */    public void resetViewPort()    {      viewPort.removeChangeListener(this);      viewPort.removePropertyChangeListener(this);      viewPort = getViewport();      viewPort.addChangeListener(this);      viewPort.addPropertyChangeListener(this);    }  }  private static final long serialVersionUID = 5203525440012340014L;    protected JViewport columnHeader;  protected JViewport rowHeader;  protected Component lowerLeft;  protected Component lowerRight;  protected Component upperLeft;  protected Component upperRight;  protected JScrollBar horizontalScrollBar;  protected int horizontalScrollBarPolicy;  protected JScrollBar verticalScrollBar;  protected int verticalScrollBarPolicy;  protected JViewport viewport;    Border viewportBorder;  boolean wheelScrollingEnabled;  public JViewport getColumnHeader()  {    return columnHeader;  }  public Component getCorner(String key) {    if (getComponentOrientation()         == ComponentOrientation.LEFT_TO_RIGHT)      {        if (key == LOWER_LEADING_CORNER)          key = LOWER_LEFT_CORNER;        else if (key == LOWER_TRAILING_CORNER)          key = LOWER_RIGHT_CORNER;        else if (key == UPPER_LEADING_CORNER)          key = UPPER_LEFT_CORNER;        else if (key == UPPER_TRAILING_CORNER)          key = UPPER_RIGHT_CORNER;      }    else if (getComponentOrientation()              == ComponentOrientation.RIGHT_TO_LEFT)      {        if (key == LOWER_LEADING_CORNER)          key = LOWER_RIGHT_CORNER;        else if (key == LOWER_TRAILING_CORNER)          key = LOWER_LEFT_CORNER;        else if (key == UPPER_LEADING_CORNER)          key = UPPER_RIGHT_CORNER;        else if (key == UPPER_TRAILING_CORNER)          key = UPPER_LEFT_CORNER;      }    if (key == LOWER_RIGHT_CORNER)      return lowerRight;    else if (key == UPPER_RIGHT_CORNER)      return upperRight;    else if (key == LOWER_LEFT_CORNER)      return lowerLeft;    else if (key == UPPER_LEFT_CORNER)      return upperLeft;    return null;  }  public JScrollBar getHorizontalScrollBar()  {    return horizontalScrollBar;  }  public int getHorizontalScrollBarPolicy()  {    return horizontalScrollBarPolicy;  }  public JViewport getRowHeader()  {    return rowHeader;  }  public JScrollBar getVerticalScrollBar()  {    return verticalScrollBar;  }  public int getVerticalScrollBarPolicy()  {    return verticalScrollBarPolicy;  }  public JViewport getViewport()  {    return viewport;  }  public Border getViewportBorder()  {    return viewportBorder;  }  public Rectangle getViewportBorderBounds()  {    if (viewportBorder == null)      {        if (getViewport() == null)          return new Rectangle(0,0,0,0);        else          return getViewport().getBounds();      }    else      {        Insets i = viewportBorder.getBorderInsets(getViewport());        if (getViewport() == null)          return new Rectangle(0,0,                               i.left+i.right, i.top+i.bottom);        else          {            Rectangle b = getViewport().getBounds();            return new Rectangle(b.x - i.left,                                  b.y - i.top,                                 b.width + i.left + i.right,                                  b.height + i.top + i.bottom);          }      }  }    public boolean isWheelScrollingEnabled()  {    return wheelScrollingEnabled;  }  private void sync()  {    LayoutManager m = super.getLayout();    if (m != null && m instanceof ScrollPaneLayout)      {        ScrollPaneLayout sl = (ScrollPaneLayout) m;        sl.syncWithScrollPane(this);      }  }  private void removeNonNull(Component c)  {    if (c != null)      remove(c);  }  private void addNonNull(Component c, Object constraints)  {    if (c != null)      add(c, constraints);  }  public void setComponentOrientation(ComponentOrientation co)  {    ComponentOrientation old = super.getComponentOrientation();    super.setComponentOrientation(co);    firePropertyChange("componentOrientation", old, co);    sync();  }  public void setColumnHeader(JViewport h)  {    if (columnHeader == h)      return;        JViewport old = columnHeader;    removeNonNull(old);    columnHeader = h;    addNonNull(h, JScrollPane.COLUMN_HEADER);    firePropertyChange("columnHeader", old, h);    sync();  }  public void setColumnHeaderView(Component c)  {    if (columnHeader == null)      setColumnHeader(createViewport());    columnHeader.setView(c);    sync();  }  public void setCorner(String key, Component c)  {    if (getComponentOrientation()         == ComponentOrientation.LEFT_TO_RIGHT)      {        if (key == LOWER_LEADING_CORNER)          key = LOWER_LEFT_CORNER;        else if (key == LOWER_TRAILING_CORNER)          key = LOWER_RIGHT_CORNER;        else if (key == UPPER_LEADING_CORNER)          key = UPPER_LEFT_CORNER;        else if (key == UPPER_TRAILING_CORNER)          key = UPPER_RIGHT_CORNER;      }    else if (getComponentOrientation()              == ComponentOrientation.RIGHT_TO_LEFT)      {        if (key == LOWER_LEADING_CORNER)          key = LOWER_RIGHT_CORNER;        else if (key == LOWER_TRAILING_CORNER)          key = LOWER_LEFT_CORNER;        else if (key == UPPER_LEADING_CORNER)          key = UPPER_RIGHT_CORNER;        else if (key == UPPER_TRAILING_CORNER)          key = UPPER_LEFT_CORNER;      }    if (key == LOWER_RIGHT_CORNER)