libjava/javax/swing/JRadioButton.java

   1 /* JRadioButton.java --
   2    Copyright (C) 2002, 2004, 2005  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package javax.swing;
  40
  41 import javax.accessibility.AccessibleContext;
  42 import javax.accessibility.AccessibleRole;
  43 import javax.swing.plaf.ButtonUI;
  44
  45 /**
  46  * The <code>JRadioButton</code> component provides a visually selectable
  47  * button with mutually exclusive behaviour within a <code>ButtonGroup</code>.
  48  * A series of radio buttons can be used to provide options to the user,
  49  * where the user can only select one of the available options.  The state
  50  * of the button is provided by the superclass, <code>JToggleButton</code>.
  51  * <code>JRadioButton</code> adds the additional behaviour, that if two
  52  * or more radio buttons are grouped together, the selection of one implies
  53  * the deselection of the other buttons within the group.
  54  * <p>
  55  *
  56  * Buttons are grouped by adding each instance to a <code>ButtonGroup</code>.
  57  * The existence of such a grouping is not reflected visually, so other means
  58  * should be used to denote this.  For instance, the grouped buttons can be placed
  59  * within the same panel, possibly with an appropriate border to denote
  60  * the connection between the components.
  61  *
  62  * @author Michael Koch  (konqueror@gmx.de)
  63  * @author Graydon Hoare  (graydon@redhat.com)
  64  * @author Andrew John Hughes  (gnu_andrew@member.fsf.org)
  65  * @see JToggleButton
  66  * @see ButtonGroup
  67  * @since 1.2
  68  */
  69 public class JRadioButton extends JToggleButton
  70 {
  71   /**
  72    * Compatible with Sun's JDK.
  73    */
  74   private static final long serialVersionUID = 7751949583255506856L;
  75
  76   /**
  77    * This class provides accessibility support for the toggle button.
  78    */
  79   protected class AccessibleJRadioButton
  80     extends AccessibleJToggleButton
  81   {
  82
  83     /**
  84      * Constructor for the accessible toggle button.
  85      */
  86     protected AccessibleJRadioButton()
  87     {
  88         /* Call the superclass to register for events */
  89         super();
  90     }
  91
  92     /**
  93      * Returns the accessible role for the toggle button.
  94      *
  95      * @return An instance of <code>AccessibleRole</code>, describing
  96      *         the role of the toggle button.
  97      */
  98     public AccessibleRole getAccessibleRole()
  99     {
 100       return AccessibleRole.RADIO_BUTTON;
 101     }
 102
 103   }
 104
 105   /**
 106    * Constructs an unselected radio button with no text or icon.
 107    */
 108   public JRadioButton()
 109   {
 110     this(null, null, false);
 111   }
 112
 113   /**
 114    * Constructs a radio button using the labelling, state
 115    * and icon specified by the supplied action.
 116    *
 117    * @param a the action to use to define the properties of the button.
 118    */
 119   public JRadioButton(Action a)
 120   {
 121     this();
 122     setAction(a);
 123   }
 124
 125   /**
 126    * Constructs an unselected radio button with the supplied icon
 127    * and no text.
 128    *
 129    * @param icon the icon to use.
 130    */
 131   public JRadioButton(Icon icon)
 132   {
 133     this(null, icon, false);
 134   }
 135
 136   /**
 137    * Constructs a radio button with the supplied icon and state.
 138    *
 139    * @param icon the icon to use.
 140    * @param selected if true, the radio button is initially in the
 141    *        selected state.  Otherwise, the button is unselected.
 142    */
 143   public JRadioButton(Icon icon, boolean selected)
 144   {
 145     this(null, icon, selected);
 146   }
 147
 148   /**
 149    * Constructs an unselected radio button using the supplied text
 150    * and no icon.
 151    *
 152    * @param text the text to use.
 153    */
 154   public JRadioButton(String text)
 155   {
 156     this(text, null, false);
 157   }
 158
 159   /**
 160    * Constructs a radio button with the supplied text and state.
 161    *
 162    * @param text the text to use.
 163    * @param selected if true, the radio button is initially in the
 164    *        selected state.  Otherwise, the button is unselected.
 165    */
 166   public JRadioButton(String text, boolean selected)
 167   {
 168     this(text, null, selected);
 169   }
 170
 171   /**
 172    * Constructs an unselected radio button with the supplied text
 173    * and icon.
 174    *
 175    * @param text the text to use.
 176    * @param icon the icon to use.
 177    */
 178   public JRadioButton(String text, Icon icon)
 179   {
 180     this(text, icon, false);
 181   }
 182
 183   /**
 184    * Constructs a radio button with the supplied text, icon and state.
 185    *
 186    * @param text the text to use.
 187    * @param icon the icon to use.
 188    * @param selected if true, the radio button is initially in the
 189    *        selected state.  Otherwise, the button is unselected.
 190    */
 191   public JRadioButton(String text, Icon icon, boolean selected)
 192   {
 193     super(text, icon, selected);
 194     borderPainted = false;
 195     contentAreaFilled = false;
 196   }
 197
 198   /**
 199    * Returns the accessible context for this <code>JRadioButton</code>,
 200    * in the form of an instance of <code>AccessibleJRadioButton</code>.
 201    * The context is created, if necessary.
 202    *
 203    * @return the associated context
 204    */
 205   public AccessibleContext getAccessibleContext()
 206   {
 207     /* Create the context if this is the first request */
 208     if (accessibleContext == null)
 209       {
 210         /* Create the context */
 211         accessibleContext = new AccessibleJRadioButton();
 212       }
 213     return accessibleContext;
 214   }
 215
 216   /**
 217    * Returns a string specifying the name of the Look and Feel UI class
 218    * that renders this component.
 219    *
 220    * @return the Look and Feel UI class for <code>JRadioButton</code>s
 221    *         as a <code>String</code>.
 222    */
 223   public String getUIClassID()
 224   {
 225     return "RadioButtonUI";
 226   }
 227
 228   /**
 229    * Returns a string representation of this component for debugging use.
 230    * Users should not depend on anything as regards the content or formatting
 231    * of this string, except for the fact that the returned string may never be
 232    * null (only empty).
 233    *
 234    * @return the component in <code>String</code> form for debugging.
 235    */
 236   protected  String paramString()
 237   {
 238     return "JRadioButton";
 239   }
 240
 241   /**
 242    * This method resets the radio button's UI delegate to the default UI for
 243    * the current look and feel.
 244    */
 245   public void updateUI()
 246   {
 247     /*
 248        I can't see any difference between this and the superclass one,
 249        but Sun reimplements it... there is no RadioButtonUI class for it
 250        to be cast to.
 251     */
 252     setUI((ButtonUI) UIManager.getUI(this));
 253   }
 254
 255 }
 256
 257
 258