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}