001/* ListUI.java --
002   Copyright (C) 2002, 2003, 2004, 2005  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.swing.plaf;
040
041import java.awt.Point;
042import java.awt.Rectangle;
043
044import javax.swing.JList;
045
046/**
047 * An abstract base class for delegates that implement the pluggable
048 * look and feel for a <code>JList</code>.
049 *
050 * @author Sascha Brawer (brawer@dandelis.ch)
051 */
052public abstract class ListUI extends ComponentUI
053{
054  /**
055   * Constructs a new <code>ListUI</code>.
056   */
057  public ListUI()
058  {
059    // Nothing to do here.
060  }
061
062
063  /**
064   * Determines the cell index which is the closest to the specified
065   * location. The find out whether the returned cell actually
066   * contains the location, the caller should also use {@link
067   * #getCellBounds}.
068   *
069   * @param list the <code>JList</code> for which this delegate object
070   *        provides the pluggable user interface.
071   *
072   * @param location a point in the <code>JList</code> coordinate
073   *        system.
074   *
075   * @return the index of the closest cell, or -1 if the list model
076   *         is empty.
077   */
078  public abstract int locationToIndex(JList list, Point location);
079
080
081  /**
082   * Determines the location of the specified cell.
083   *
084   * @param list the <code>JList</code> for which this delegate object
085   *        provides the pluggable user interface.
086   *
087   * @param index the zero-based index of the cell whose location shall be
088   *        determined.
089   *
090   * @return the position of the top left corner of the cell in the
091   *         <code>JList</code> coordinate system, or <code>null</code>
092   *         if <code>cell</code> does not designate a valid cell.
093   */
094  public abstract Point indexToLocation(JList list, int index);
095
096
097  /**
098   * Determines the bounding box of the rectangle spanned by
099   * two list indices.
100   *
101   * @param list the <code>JList</code> for which this delegate object
102   *        provides the pluggable user interface.
103   *
104   * @param index1 the zero-based index of the first cell.
105   *
106   * @param index2 the zero-based index of the second cell.
107   *
108   * @return the spanned rectangle, or <code>null</code> if either
109   *         <code>index1</code> or <code>index2</code> does not
110   *         designate a valid cell.
111   */
112  public abstract Rectangle getCellBounds(JList list,
113                                          int index1, int index2);
114}