ListUI.java

/* ListUI.java --
   Copyright (C) 2002, 2003, 2004, 2005  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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General Public License for more details.

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02110-1301 USA.

Linking this library statically or dynamically with other modules is
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permission to link this library with independent modules to produce an
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package javax.swing.plaf;

import java.awt.Point;
import java.awt.Rectangle;

import javax.swing.JList;

/**
 * An abstract base class for delegates that implement the pluggable
 * look and feel for a <code>JList</code>.
 *
 * @author Sascha Brawer (brawer@dandelis.ch)
 */
public abstract class ListUI extends ComponentUI
{
  /**
   * Constructs a new <code>ListUI</code>.
   */
  public ListUI()
  {
    // Nothing to do here.
  }


  /**
   * Determines the cell index which is the closest to the specified
   * location. The find out whether the returned cell actually
   * contains the location, the caller should also use {@link
   * #getCellBounds}.
   *
   * @param list the <code>JList</code> for which this delegate object
   *        provides the pluggable user interface.
   *
   * @param location a point in the <code>JList</code> coordinate
   *        system.
   *
   * @return the index of the closest cell, or -1 if the list model
   *         is empty.
   */
  public abstract int locationToIndex(JList list, Point location);


  /**
   * Determines the location of the specified cell.
   *
   * @param list the <code>JList</code> for which this delegate object
   *        provides the pluggable user interface.
   *
   * @param index the zero-based index of the cell whose location shall be
   *        determined.
   *
   * @return the position of the top left corner of the cell in the
   *         <code>JList</code> coordinate system, or <code>null</code>
   *         if <code>cell</code> does not designate a valid cell.
   */
  public abstract Point indexToLocation(JList list, int index);


  /**
   * Determines the bounding box of the rectangle spanned by
   * two list indices.
   *
   * @param list the <code>JList</code> for which this delegate object
   *        provides the pluggable user interface.
   *
   * @param index1 the zero-based index of the first cell.
   *
   * @param index2 the zero-based index of the second cell.
   *
   * @return the spanned rectangle, or <code>null</code> if either
   *         <code>index1</code> or <code>index2</code> does not
   *         designate a valid cell.
   */
  public abstract Rectangle getCellBounds(JList list,
                                          int index1, int index2);
}