1 /*
   2  * Copyright (c) 1997, 2014, 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="http://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="http://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  * @since 1.2
  86  */
  87 @SuppressWarnings("serial") // Same-version serialization only
  88 public class JRadioButtonMenuItem extends JMenuItem implements Accessible {
  89     /**
  90      * @see #getUIClassID
  91      * @see #readObject
  92      */
  93     private static final String uiClassID = "RadioButtonMenuItemUI";
  94 
  95     /**
  96      * Creates a <code>JRadioButtonMenuItem</code> with no set text or icon.
  97      */
  98     public JRadioButtonMenuItem() {
  99         this(null, null, false);
 100     }
 101 
 102     /**
 103      * Creates a <code>JRadioButtonMenuItem</code> with an icon.
 104      *
 105      * @param icon the <code>Icon</code> to display on the
 106      *          <code>JRadioButtonMenuItem</code>
 107      */
 108     public JRadioButtonMenuItem(Icon icon) {
 109         this(null, icon, false);
 110     }
 111 
 112     /**
 113      * Creates a <code>JRadioButtonMenuItem</code> with text.
 114      *
 115      * @param text the text of the <code>JRadioButtonMenuItem</code>
 116      */
 117     public JRadioButtonMenuItem(String text) {
 118         this(text, null, false);
 119     }
 120 
 121     /**
 122      * Creates a radio button menu item whose properties are taken from the
 123      * <code>Action</code> supplied.
 124      *
 125      * @param  a the <code>Action</code> on which to base the radio
 126      *          button menu item
 127      *
 128      * @since 1.3
 129      */
 130     public JRadioButtonMenuItem(Action a) {
 131         this();
 132         setAction(a);
 133     }
 134 
 135     /**
 136      * Creates a radio button menu item with the specified text
 137      * and <code>Icon</code>.
 138      *
 139      * @param text the text of the <code>JRadioButtonMenuItem</code>
 140      * @param icon the icon to display on the <code>JRadioButtonMenuItem</code>
 141      */
 142     public JRadioButtonMenuItem(String text, Icon icon) {
 143         this(text, icon, false);
 144     }
 145 
 146     /**
 147      * Creates a radio button menu item with the specified text
 148      * and selection state.
 149      *
 150      * @param text the text of the <code>CheckBoxMenuItem</code>
 151      * @param selected the selected state of the <code>CheckBoxMenuItem</code>
 152      */
 153     public JRadioButtonMenuItem(String text, boolean selected) {
 154         this(text);
 155         setSelected(selected);
 156     }
 157 
 158     /**
 159      * Creates a radio button menu item with the specified image
 160      * and selection state, but no text.
 161      *
 162      * @param icon  the image that the button should display
 163      * @param selected  if true, the button is initially selected;
 164      *                  otherwise, the button is initially unselected
 165      */
 166     public JRadioButtonMenuItem(Icon icon, boolean selected) {
 167         this(null, icon, selected);
 168     }
 169 
 170     /**
 171      * Creates a radio button menu item that has the specified
 172      * text, image, and selection state.  All other constructors
 173      * defer to this one.
 174      *
 175      * @param text  the string displayed on the radio button
 176      * @param icon  the image that the button should display
 177      */
 178     public JRadioButtonMenuItem(String text, Icon icon, boolean selected) {
 179         super(text, icon);
 180         setModel(new JToggleButton.ToggleButtonModel());
 181         setSelected(selected);
 182         setFocusable(false);
 183     }
 184 
 185     /**
 186      * Returns the name of the L&amp;F class that renders this component.
 187      *
 188      * @return the string "RadioButtonMenuItemUI"
 189      * @see JComponent#getUIClassID
 190      * @see UIDefaults#getUI
 191      */
 192     public String getUIClassID() {
 193         return uiClassID;
 194     }
 195 
 196     /**
 197      * See <code>readObject</code> and <code>writeObject</code> in
 198      * <code>JComponent</code> for more
 199      * information about serialization in Swing.
 200      */
 201     private void writeObject(ObjectOutputStream s) throws IOException {
 202         s.defaultWriteObject();
 203         if (getUIClassID().equals(uiClassID)) {
 204             byte count = JComponent.getWriteObjCounter(this);
 205             JComponent.setWriteObjCounter(this, --count);
 206             if (count == 0 && ui != null) {
 207                 ui.installUI(this);
 208             }
 209         }
 210     }
 211 
 212 
 213     /**
 214      * Returns a string representation of this
 215      * <code>JRadioButtonMenuItem</code>.  This method
 216      * is intended to be used only for debugging purposes, and the
 217      * content and format of the returned string may vary between
 218      * implementations. The returned string may be empty but may not
 219      * be <code>null</code>.
 220      *
 221      * @return  a string representation of this
 222      *          <code>JRadioButtonMenuItem</code>
 223      */
 224     protected String paramString() {
 225         return super.paramString();
 226     }
 227 
 228     /**
 229      * Overriden to return true, JRadioButtonMenuItem supports
 230      * the selected state.
 231      */
 232     boolean shouldUpdateSelectedStateFromAction() {
 233         return true;
 234     }
 235 
 236 /////////////////
 237 // Accessibility support
 238 ////////////////
 239 
 240     /**
 241      * Gets the AccessibleContext associated with this JRadioButtonMenuItem.
 242      * For JRadioButtonMenuItems, the AccessibleContext takes the form of an
 243      * AccessibleJRadioButtonMenuItem.
 244      * A new AccessibleJRadioButtonMenuItem instance is created if necessary.
 245      *
 246      * @return an AccessibleJRadioButtonMenuItem that serves as the
 247      *         AccessibleContext of this JRadioButtonMenuItem
 248      */
 249     public AccessibleContext getAccessibleContext() {
 250         if (accessibleContext == null) {
 251             accessibleContext = new AccessibleJRadioButtonMenuItem();
 252         }
 253         return accessibleContext;
 254     }
 255 
 256     /**
 257      * This class implements accessibility support for the
 258      * <code>JRadioButtonMenuItem</code> class.  It provides an
 259      * implementation of the Java Accessibility API appropriate to
 260      * <code>JRadioButtonMenuItem</code> user-interface elements.
 261      * <p>
 262      * <strong>Warning:</strong>
 263      * Serialized objects of this class will not be compatible with
 264      * future Swing releases. The current serialization support is
 265      * appropriate for short term storage or RMI between applications running
 266      * the same version of Swing.  As of 1.4, support for long term storage
 267      * of all JavaBeans&trade;
 268      * has been added to the <code>java.beans</code> package.
 269      * Please see {@link java.beans.XMLEncoder}.
 270      */
 271     @SuppressWarnings("serial") // Same-version serialization only
 272     protected class AccessibleJRadioButtonMenuItem extends AccessibleJMenuItem {
 273         /**
 274          * Get the role of this object.
 275          *
 276          * @return an instance of AccessibleRole describing the role of the
 277          * object
 278          */
 279         public AccessibleRole getAccessibleRole() {
 280             return AccessibleRole.RADIO_BUTTON;
 281         }
 282     } // inner class AccessibleJRadioButtonMenuItem
 283 }