1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package javax.swing;
  26 
  27 import java.util.EventListener;
  28 
  29 import java.awt.*;
  30 import java.awt.event.*;
  31 import java.awt.image.*;
  32 
  33 import java.io.ObjectOutputStream;
  34 import java.io.ObjectInputStream;
  35 import java.io.IOException;
  36 
  37 import javax.swing.plaf.*;
  38 import javax.accessibility.*;
  39 
  40 /**
  41  * An implementation of a radio button menu item.
  42  * A <code>JRadioButtonMenuItem</code> is
  43  * a menu item that is part of a group of menu items in which only one
  44  * item in the group can be selected. The selected item displays its
  45  * selected state. Selecting it causes any other selected item to
  46  * switch to the unselected state.
  47  * To control the selected state of a group of radio button menu items,
  48  * use a <code>ButtonGroup</code> object.
  49  * <p>
  50  * Menu items can be configured, and to some degree controlled, by
  51  * <code><a href="Action.html">Action</a></code>s.  Using an
  52  * <code>Action</code> with a menu item has many benefits beyond directly
  53  * configuring a menu item.  Refer to <a href="Action.html#buttonActions">
  54  * Swing Components Supporting <code>Action</code></a> for more
  55  * details, and you can find more information in <a
  56  * href="https://docs.oracle.com/javase/tutorial/uiswing/misc/action.html">How
  57  * to Use Actions</a>, a section in <em>The Java Tutorial</em>.
  58  * <p>
  59  * For further documentation and examples see
  60  * <a
  61  href="https://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
  62  * a section in <em>The Java Tutorial.</em>
  63  * <p>
  64  * <strong>Warning:</strong> Swing is not thread safe. For more
  65  * information see <a
  66  * href="package-summary.html#threading">Swing's Threading
  67  * Policy</a>.
  68  * <p>
  69  * <strong>Warning:</strong>
  70  * Serialized objects of this class will not be compatible with
  71  * future Swing releases. The current serialization support is
  72  * appropriate for short term storage or RMI between applications running
  73  * the same version of Swing.  As of 1.4, support for long term storage
  74  * of all JavaBeans&trade;
  75  * has been added to the <code>java.beans</code> package.
  76  * Please see {@link java.beans.XMLEncoder}.
  77  *
  78  * @beaninfo
  79  *   attribute: isContainer false
  80  * description: A component within a group of menu items which can be selected.
  81  *
  82  * @author Georges Saab
  83  * @author David Karlton
  84  * @see ButtonGroup
  85  */
  86 public class JRadioButtonMenuItem extends JMenuItem implements Accessible {
  87     /**
  88      * @see #getUIClassID
  89      * @see #readObject
  90      */
  91     private static final String uiClassID = "RadioButtonMenuItemUI";
  92 
  93     /**
  94      * Creates a <code>JRadioButtonMenuItem</code> with no set text or icon.
  95      */
  96     public JRadioButtonMenuItem() {
  97         this(null, null, false);
  98     }
  99 
 100     /**
 101      * Creates a <code>JRadioButtonMenuItem</code> with an icon.
 102      *
 103      * @param icon the <code>Icon</code> to display on the
 104      *          <code>JRadioButtonMenuItem</code>
 105      */
 106     public JRadioButtonMenuItem(Icon icon) {
 107         this(null, icon, false);
 108     }
 109 
 110     /**
 111      * Creates a <code>JRadioButtonMenuItem</code> with text.
 112      *
 113      * @param text the text of the <code>JRadioButtonMenuItem</code>
 114      */
 115     public JRadioButtonMenuItem(String text) {
 116         this(text, null, false);
 117     }
 118 
 119     /**
 120      * Creates a radio button menu item whose properties are taken from the
 121      * <code>Action</code> supplied.
 122      *
 123      * @param  a the <code>Action</code> on which to base the radio
 124      *          button menu item
 125      *
 126      * @since 1.3
 127      */
 128     public JRadioButtonMenuItem(Action a) {
 129         this();
 130         setAction(a);
 131     }
 132 
 133     /**
 134      * Creates a radio button menu item with the specified text
 135      * and <code>Icon</code>.
 136      *
 137      * @param text the text of the <code>JRadioButtonMenuItem</code>
 138      * @param icon the icon to display on the <code>JRadioButtonMenuItem</code>
 139      */
 140     public JRadioButtonMenuItem(String text, Icon icon) {
 141         this(text, icon, false);
 142     }
 143 
 144     /**
 145      * Creates a radio button menu item with the specified text
 146      * and selection state.
 147      *
 148      * @param text the text of the <code>CheckBoxMenuItem</code>
 149      * @param selected the selected state of the <code>CheckBoxMenuItem</code>
 150      */
 151     public JRadioButtonMenuItem(String text, boolean selected) {
 152         this(text);
 153         setSelected(selected);
 154     }
 155 
 156     /**
 157      * Creates a radio button menu item with the specified image
 158      * and selection state, but no text.
 159      *
 160      * @param icon  the image that the button should display
 161      * @param selected  if true, the button is initially selected;
 162      *                  otherwise, the button is initially unselected
 163      */
 164     public JRadioButtonMenuItem(Icon icon, boolean selected) {
 165         this(null, icon, selected);
 166     }
 167 
 168     /**
 169      * Creates a radio button menu item that has the specified
 170      * text, image, and selection state.  All other constructors
 171      * defer to this one.
 172      *
 173      * @param text  the string displayed on the radio button
 174      * @param icon  the image that the button should display
 175      */
 176     public JRadioButtonMenuItem(String text, Icon icon, boolean selected) {
 177         super(text, icon);
 178         setModel(new JToggleButton.ToggleButtonModel());
 179         setSelected(selected);
 180         setFocusable(false);
 181     }
 182 
 183     /**
 184      * Returns the name of the L&amp;F class that renders this component.
 185      *
 186      * @return the string "RadioButtonMenuItemUI"
 187      * @see JComponent#getUIClassID
 188      * @see UIDefaults#getUI
 189      */
 190     public String getUIClassID() {
 191         return uiClassID;
 192     }
 193 
 194     /**
 195      * See <code>readObject</code> and <code>writeObject</code> in
 196      * <code>JComponent</code> for more
 197      * information about serialization in Swing.
 198      */
 199     private void writeObject(ObjectOutputStream s) throws IOException {
 200         s.defaultWriteObject();
 201         if (getUIClassID().equals(uiClassID)) {
 202             byte count = JComponent.getWriteObjCounter(this);
 203             JComponent.setWriteObjCounter(this, --count);
 204             if (count == 0 && ui != null) {
 205                 ui.installUI(this);
 206             }
 207         }
 208     }
 209 
 210 
 211     /**
 212      * Returns a string representation of this
 213      * <code>JRadioButtonMenuItem</code>.  This method
 214      * is intended to be used only for debugging purposes, and the
 215      * content and format of the returned string may vary between
 216      * implementations. The returned string may be empty but may not
 217      * be <code>null</code>.
 218      *
 219      * @return  a string representation of this
 220      *          <code>JRadioButtonMenuItem</code>
 221      */
 222     protected String paramString() {
 223         return super.paramString();
 224     }
 225 
 226     /**
 227      * Overriden to return true, JRadioButtonMenuItem supports
 228      * the selected state.
 229      */
 230     boolean shouldUpdateSelectedStateFromAction() {
 231         return true;
 232     }
 233 
 234 /////////////////
 235 // Accessibility support
 236 ////////////////
 237 
 238     /**
 239      * Gets the AccessibleContext associated with this JRadioButtonMenuItem.
 240      * For JRadioButtonMenuItems, the AccessibleContext takes the form of an
 241      * AccessibleJRadioButtonMenuItem.
 242      * A new AccessibleJRadioButtonMenuItem instance is created if necessary.
 243      *
 244      * @return an AccessibleJRadioButtonMenuItem that serves as the
 245      *         AccessibleContext of this JRadioButtonMenuItem
 246      */
 247     public AccessibleContext getAccessibleContext() {
 248         if (accessibleContext == null) {
 249             accessibleContext = new AccessibleJRadioButtonMenuItem();
 250         }
 251         return accessibleContext;
 252     }
 253 
 254     /**
 255      * This class implements accessibility support for the
 256      * <code>JRadioButtonMenuItem</code> class.  It provides an
 257      * implementation of the Java Accessibility API appropriate to
 258      * <code>JRadioButtonMenuItem</code> user-interface elements.
 259      * <p>
 260      * <strong>Warning:</strong>
 261      * Serialized objects of this class will not be compatible with
 262      * future Swing releases. The current serialization support is
 263      * appropriate for short term storage or RMI between applications running
 264      * the same version of Swing.  As of 1.4, support for long term storage
 265      * of all JavaBeans&trade;
 266      * has been added to the <code>java.beans</code> package.
 267      * Please see {@link java.beans.XMLEncoder}.
 268      */
 269     protected class AccessibleJRadioButtonMenuItem extends AccessibleJMenuItem {
 270         /**
 271          * Get the role of this object.
 272          *
 273          * @return an instance of AccessibleRole describing the role of the
 274          * object
 275          */
 276         public AccessibleRole getAccessibleRole() {
 277             return AccessibleRole.RADIO_BUTTON;
 278         }
 279     } // inner class AccessibleJRadioButtonMenuItem
 280 }