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.beans.JavaBean;
28 import java.beans.BeanProperty;
29
30 import javax.swing.plaf.*;
31 import javax.accessibility.*;
32
33 import java.io.ObjectOutputStream;
34 import java.io.IOException;
35
36 /**
37 * An implementation of a radio button -- an item that can be selected or
38 * deselected, and which displays its state to the user.
39 * Used with a {@link ButtonGroup} object to create a group of buttons
40 * in which only one button at a time can be selected. (Create a ButtonGroup
41 * object and use its <code>add</code> method to include the JRadioButton objects
42 * in the group.)
43 * <blockquote>
44 * <strong>Note:</strong>
45 * The ButtonGroup object is a logical grouping -- not a physical grouping.
46 * To create a button panel, you should still create a {@link JPanel} or similar
47 * container-object and add a {@link javax.swing.border.Border} to it to set it off from surrounding
48 * components.
49 * </blockquote>
50 * <p>
51 * Buttons can be configured, and to some degree controlled, by
52 * <code><a href="Action.html">Action</a></code>s. Using an
53 * <code>Action</code> with a button has many benefits beyond directly
54 * configuring a button. Refer to <a href="Action.html#buttonActions">
55 * Swing Components Supporting <code>Action</code></a> for more
56 * details, and you can find more information in <a
57 * href="http://docs.oracle.com/javase/tutorial/uiswing/misc/action.html">How
58 * to Use Actions</a>, a section in <em>The Java Tutorial</em>.
59 * <p>
60 * See <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/button.html">How to Use Buttons, Check Boxes, and Radio Buttons</a>
61 * in <em>The Java Tutorial</em>
62 * for further documentation.
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™
75 * has been added to the <code>java.beans</code> package.
76 * Please see {@link java.beans.XMLEncoder}.
77 *
78 * @see ButtonGroup
79 * @see JCheckBox
80 * @author Jeff Dinkins
81 * @since 1.2
82 */
83 @JavaBean(description = "A component which can display it's state as selected or deselected.")
84 @SwingContainer(false)
85 @SuppressWarnings("serial") // Same-version serialization only
86 public class JRadioButton extends JToggleButton implements Accessible {
87
88 /**
89 * @see #getUIClassID
90 * @see #readObject
91 */
92 private static final String uiClassID = "RadioButtonUI";
93
94
95 /**
96 * Creates an initially unselected radio button
97 * with no set text.
98 */
99 public JRadioButton () {
100 this(null, null, false);
101 }
102
103 /**
104 * Creates an initially unselected radio button
105 * with the specified image but no text.
106 *
107 * @param icon the image that the button should display
108 */
109 public JRadioButton(Icon icon) {
110 this(null, icon, false);
111 }
112
113 /**
114 * Creates a radiobutton where properties are taken from the
115 * Action supplied.
116 *
117 * @param a an {@code Action}
118 * @since 1.3
119 */
120 public JRadioButton(Action a) {
121 this();
122 setAction(a);
123 }
124
125 /**
126 * Creates a radio button with the specified image
127 * and selection state, but no text.
128 *
129 * @param icon the image that the button should display
130 * @param selected if true, the button is initially selected;
131 * otherwise, the button is initially unselected
132 */
133 public JRadioButton(Icon icon, boolean selected) {
134 this(null, icon, selected);
135 }
136
137 /**
138 * Creates an unselected radio button with the specified text.
139 *
140 * @param text the string displayed on the radio button
141 */
142 public JRadioButton (String text) {
143 this(text, null, false);
144 }
145
146 /**
147 * Creates a radio button with the specified text
148 * and selection state.
149 *
150 * @param text the string displayed on the radio button
151 * @param selected if true, the button is initially selected;
152 * otherwise, the button is initially unselected
153 */
154 public JRadioButton (String text, boolean selected) {
155 this(text, null, selected);
156 }
157
158 /**
159 * Creates a radio button that has the specified text and image,
160 * and that is initially unselected.
161 *
162 * @param text the string displayed on the radio button
163 * @param icon the image that the button should display
164 */
165 public JRadioButton(String text, Icon icon) {
166 this(text, icon, false);
167 }
168
169 /**
170 * Creates a radio button that has the specified text, image,
171 * and selection state.
172 *
173 * @param text the string displayed on the radio button
174 * @param icon the image that the button should display
175 * @param selected if {@code true}, the button is initially selected
176 * otherwise, the button is initially unselected
177 */
178 public JRadioButton (String text, Icon icon, boolean selected) {
179 super(text, icon, selected);
180 setBorderPainted(false);
181 setHorizontalAlignment(LEADING);
182 }
183
184
185 /**
186 * Resets the UI property to a value from the current look and feel.
187 *
188 * @see JComponent#updateUI
189 */
190 public void updateUI() {
191 setUI((ButtonUI)UIManager.getUI(this));
192 }
193
194
195 /**
196 * Returns the name of the L&F class
197 * that renders this component.
198 *
199 * @return String "RadioButtonUI"
200 * @see JComponent#getUIClassID
201 * @see UIDefaults#getUI
202 */
203 @BeanProperty(bound = false, expert = true, description
204 = "A string that specifies the name of the L&F class.")
205 public String getUIClassID() {
206 return uiClassID;
207 }
208
209
210 /**
211 * The icon for radio buttons comes from the look and feel,
212 * not the Action.
213 */
214 void setIconFromAction(Action a) {
215 }
216
217 /**
218 * See readObject() and writeObject() in JComponent for more
219 * information about serialization in Swing.
220 */
221 private void writeObject(ObjectOutputStream s) throws IOException {
222 s.defaultWriteObject();
223 if (getUIClassID().equals(uiClassID)) {
224 byte count = JComponent.getWriteObjCounter(this);
225 JComponent.setWriteObjCounter(this, --count);
226 if (count == 0 && ui != null) {
227 ui.installUI(this);
228 }
229 }
230 }
231
232
233 /**
234 * Returns a string representation of this JRadioButton. This method
235 * is intended to be used only for debugging purposes, and the
236 * content and format of the returned string may vary between
237 * implementations. The returned string may be empty but may not
238 * be <code>null</code>.
239 *
240 * @return a string representation of this JRadioButton.
241 */
242 protected String paramString() {
243 return super.paramString();
244 }
245
246
247 /////////////////
248 // Accessibility support
249 ////////////////
250
251
252 /**
253 * Gets the AccessibleContext associated with this JRadioButton.
254 * For JRadioButtons, the AccessibleContext takes the form of an
255 * AccessibleJRadioButton.
256 * A new AccessibleJRadioButton instance is created if necessary.
257 *
258 * @return an AccessibleJRadioButton that serves as the
259 * AccessibleContext of this JRadioButton
260 */
261 @BeanProperty(bound = false, expert = true, description
262 = "The AccessibleContext associated with this Button")
263 public AccessibleContext getAccessibleContext() {
264 if (accessibleContext == null) {
265 accessibleContext = new AccessibleJRadioButton();
266 }
267 return accessibleContext;
268 }
269
270 /**
271 * This class implements accessibility support for the
272 * <code>JRadioButton</code> class. It provides an implementation of the
273 * Java Accessibility API appropriate to radio button
274 * user-interface elements.
275 * <p>
276 * <strong>Warning:</strong>
277 * Serialized objects of this class will not be compatible with
278 * future Swing releases. The current serialization support is
279 * appropriate for short term storage or RMI between applications running
280 * the same version of Swing. As of 1.4, support for long term storage
281 * of all JavaBeans™
282 * has been added to the <code>java.beans</code> package.
283 * Please see {@link java.beans.XMLEncoder}.
284 */
285 @SuppressWarnings("serial") // Same-version serialization only
286 protected class AccessibleJRadioButton extends AccessibleJToggleButton {
287
288 /**
289 * Get the role of this object.
290 *
291 * @return an instance of AccessibleRole describing the role of the object
292 * @see AccessibleRole
293 */
294 public AccessibleRole getAccessibleRole() {
295 return AccessibleRole.RADIO_BUTTON;
296 }
297
298 } // inner class AccessibleJRadioButton
299 }