001    /* ListUI.java --
002       Copyright (C) 2002, 2003, 2004, 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.swing.plaf;
040    
041    import java.awt.Point;
042    import java.awt.Rectangle;
043    
044    import 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     */
052    public 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    }