001/* JRadioButton.java -- 002 Copyright (C) 2002, 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; 040 041import javax.accessibility.AccessibleContext; 042import javax.accessibility.AccessibleRole; 043import javax.swing.plaf.ButtonUI; 044 045/** 046 * The <code>JRadioButton</code> component provides a visually selectable 047 * button with mutually exclusive behaviour within a <code>ButtonGroup</code>. 048 * A series of radio buttons can be used to provide options to the user, 049 * where the user can only select one of the available options. The state 050 * of the button is provided by the superclass, <code>JToggleButton</code>. 051 * <code>JRadioButton</code> adds the additional behaviour, that if two 052 * or more radio buttons are grouped together, the selection of one implies 053 * the deselection of the other buttons within the group. 054 * <p> 055 * 056 * Buttons are grouped by adding each instance to a <code>ButtonGroup</code>. 057 * The existence of such a grouping is not reflected visually, so other means 058 * should be used to denote this. For instance, the grouped buttons can be placed 059 * within the same panel, possibly with an appropriate border to denote 060 * the connection between the components. 061 * 062 * @author Michael Koch (konqueror@gmx.de) 063 * @author Graydon Hoare (graydon@redhat.com) 064 * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 065 * @see JToggleButton 066 * @see ButtonGroup 067 * @since 1.2 068 */ 069public class JRadioButton extends JToggleButton 070{ 071 /** 072 * Compatible with Sun's JDK. 073 */ 074 private static final long serialVersionUID = 7751949583255506856L; 075 076 /** 077 * This class provides accessibility support for the toggle button. 078 */ 079 protected class AccessibleJRadioButton 080 extends AccessibleJToggleButton 081 { 082 private static final long serialVersionUID = 4850967637026120674L; 083 084 /** 085 * Constructor for the accessible toggle button. 086 */ 087 protected AccessibleJRadioButton() 088 { 089 /* Call the superclass to register for events */ 090 super(); 091 } 092 093 /** 094 * Returns the accessible role for the toggle button. 095 * 096 * @return An instance of <code>AccessibleRole</code>, describing 097 * the role of the toggle button. 098 */ 099 public AccessibleRole getAccessibleRole() 100 { 101 return AccessibleRole.RADIO_BUTTON; 102 } 103 104 } 105 106 /** 107 * Constructs an unselected radio button with no text or icon. 108 */ 109 public JRadioButton() 110 { 111 this(null, null, false); 112 } 113 114 /** 115 * Constructs a radio button using the labelling, state 116 * and icon specified by the supplied action. 117 * 118 * @param a the action to use to define the properties of the button. 119 */ 120 public JRadioButton(Action a) 121 { 122 this(); 123 setAction(a); 124 } 125 126 /** 127 * Constructs an unselected radio button with the supplied icon 128 * and no text. 129 * 130 * @param icon the icon to use. 131 */ 132 public JRadioButton(Icon icon) 133 { 134 this(null, icon, false); 135 } 136 137 /** 138 * Constructs a radio button with the supplied icon and state. 139 * 140 * @param icon the icon to use. 141 * @param selected if true, the radio button is initially in the 142 * selected state. Otherwise, the button is unselected. 143 */ 144 public JRadioButton(Icon icon, boolean selected) 145 { 146 this(null, icon, selected); 147 } 148 149 /** 150 * Constructs an unselected radio button using the supplied text 151 * and no icon. 152 * 153 * @param text the text to use. 154 */ 155 public JRadioButton(String text) 156 { 157 this(text, null, false); 158 } 159 160 /** 161 * Constructs a radio button with the supplied text and state. 162 * 163 * @param text the text to use. 164 * @param selected if true, the radio button is initially in the 165 * selected state. Otherwise, the button is unselected. 166 */ 167 public JRadioButton(String text, boolean selected) 168 { 169 this(text, null, selected); 170 } 171 172 /** 173 * Constructs an unselected radio button with the supplied text 174 * and icon. 175 * 176 * @param text the text to use. 177 * @param icon the icon to use. 178 */ 179 public JRadioButton(String text, Icon icon) 180 { 181 this(text, icon, false); 182 } 183 184 /** 185 * Constructs a radio button with the supplied text, icon and state. 186 * 187 * @param text the text to use. 188 * @param icon the icon to use. 189 * @param selected if true, the radio button is initially in the 190 * selected state. Otherwise, the button is unselected. 191 */ 192 public JRadioButton(String text, Icon icon, boolean selected) 193 { 194 super(text, icon, selected); 195 setBorderPainted(false); 196 setHorizontalAlignment(LEADING); 197 } 198 199 /** 200 * Returns the accessible context for this <code>JRadioButton</code>, 201 * in the form of an instance of <code>AccessibleJRadioButton</code>. 202 * The context is created, if necessary. 203 * 204 * @return the associated context 205 */ 206 public AccessibleContext getAccessibleContext() 207 { 208 /* Create the context if this is the first request */ 209 if (accessibleContext == null) 210 { 211 /* Create the context */ 212 accessibleContext = new AccessibleJRadioButton(); 213 } 214 return accessibleContext; 215 } 216 217 /** 218 * Returns a string specifying the name of the Look and Feel UI class 219 * that renders this component. 220 * 221 * @return the Look and Feel UI class for <code>JRadioButton</code>s 222 * as a <code>String</code>. 223 */ 224 public String getUIClassID() 225 { 226 return "RadioButtonUI"; 227 } 228 229 /** 230 * Returns a string representation of this component for debugging use. 231 * Users should not depend on anything as regards the content or formatting 232 * of this string, except for the fact that the returned string may never be 233 * null (only empty). 234 * 235 * @return the component in <code>String</code> form for debugging. 236 */ 237 protected String paramString() 238 { 239 return super.paramString(); 240 } 241 242 /** 243 * This method resets the radio button's UI delegate to the default UI for 244 * the current look and feel. 245 */ 246 public void updateUI() 247 { 248 /* 249 I can't see any difference between this and the superclass one, 250 but Sun reimplements it... there is no RadioButtonUI class for it 251 to be cast to. 252 */ 253 setUI((ButtonUI) UIManager.getUI(this)); 254 } 255 256} 257 258 259