001/* SingleSelectionModel.java --
002   Copyright (C) 2002, 2004 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
038package javax.swing;
039
040import javax.swing.event.ChangeEvent;
041import javax.swing.event.ChangeListener;
042
043/**
044 * A data model that is used in components that support at most one
045 * selected element, like {@link JTabbedPane}, {@link JMenu} and
046 * {@link JPopupMenu}.
047 *
048 * @author Andrew Selkirk
049 */
050public interface SingleSelectionModel
051{
052  /**
053   * Returns the selected index or <code>-1</code> if there is no selection.
054   *
055   * @return The selected index.
056   *
057   * @see #setSelectedIndex(int)
058   */
059  int getSelectedIndex();
060
061  /**
062   * Sets the selected index and, if this is different to the previous
063   * selection, sends a {@link ChangeEvent} to all registered listeners.
064   *
065   * @param index  the index (use <code>-1</code> to represent no selection).
066   *
067   * @see #getSelectedIndex()
068   * @see #clearSelection
069   */
070  void setSelectedIndex(int index);
071
072  /**
073   * Clears the selection by setting the selected index to <code>-1</code> and
074   * sends a {@link ChangeEvent} to all registered listeners.  If the selected
075   * index is already <code>-1</code>, this method does nothing.
076   */
077  void clearSelection();
078
079  /**
080   * Returns <code>true</code> if there is a selection, and <code>false</code>
081   * otherwise.
082   *
083   * @return A boolean.
084   */
085  boolean isSelected();
086
087  /**
088   * Registers a listener to receive {@link ChangeEvent} notifications from
089   * this model whenever the selected index changes.
090   *
091   * @param listener the listener to add.
092   */
093  void addChangeListener(ChangeListener listener);
094
095  /**
096   * Deregisters a listener so that it no longer receives {@link ChangeEvent}
097   * notifications from this model.
098   *
099   * @param listener the listener to remove.
100   */
101  void removeChangeListener(ChangeListener listener);
102
103}