1 /*
2 * Copyright (c) 1997, 2006, 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.awt.*;
28 import java.awt.event.*;
29 import java.beans.*;
30
31 import javax.swing.plaf.*;
32 import javax.accessibility.*;
33
34 import java.io.ObjectOutputStream;
35 import java.io.ObjectInputStream;
36 import java.io.IOException;
37
38
39 /**
40 * An implementation of a check box -- an item that can be selected or
41 * deselected, and which displays its state to the user.
42 * By convention, any number of check boxes in a group can be selected.
43 * See <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/button.html">How to Use Buttons, Check Boxes, and Radio Buttons</a>
44 * in <em>The Java Tutorial</em>
45 * for examples and information on using check boxes.
46 * <p>
47 * Buttons can be configured, and to some degree controlled, by
48 * <code><a href="Action.html">Action</a></code>s. Using an
49 * <code>Action</code> with a button has many benefits beyond directly
50 * configuring a button. Refer to <a href="Action.html#buttonActions">
51 * Swing Components Supporting <code>Action</code></a> for more
52 * details, and you can find more information in <a
53 * href="http://docs.oracle.com/javase/tutorial/uiswing/misc/action.html">How
54 * to Use Actions</a>, a section in <em>The Java Tutorial</em>.
55 * <p>
56 * <strong>Warning:</strong> Swing is not thread safe. For more
57 * information see <a
58 * href="package-summary.html#threading">Swing's Threading
59 * Policy</a>.
60 * <p>
61 * <strong>Warning:</strong>
62 * Serialized objects of this class will not be compatible with
63 * future Swing releases. The current serialization support is
64 * appropriate for short term storage or RMI between applications running
65 * the same version of Swing. As of 1.4, support for long term storage
66 * of all JavaBeans<sup><font size="-2">TM</font></sup>
67 * has been added to the <code>java.beans</code> package.
68 * Please see {@link java.beans.XMLEncoder}.
69 *
70 * @see JRadioButton
71 *
72 * @beaninfo
73 * attribute: isContainer false
74 * description: A component which can be selected or deselected.
75 *
76 * @author Jeff Dinkins
77 */
78 public class JCheckBox extends JToggleButton implements Accessible {
79
80 /** Identifies a change to the flat property. */
81 public static final String BORDER_PAINTED_FLAT_CHANGED_PROPERTY = "borderPaintedFlat";
82
83 private boolean flat = false;
84
85 /**
86 * @see #getUIClassID
87 * @see #readObject
88 */
89 private static final String uiClassID = "CheckBoxUI";
90
91
92 /**
93 * Creates an initially unselected check box button with no text, no icon.
94 */
95 public JCheckBox () {
96 this(null, null, false);
97 }
98
99 /**
100 * Creates an initially unselected check box with an icon.
101 *
102 * @param icon the Icon image to display
103 */
104 public JCheckBox(Icon icon) {
105 this(null, icon, false);
106 }
107
108 /**
109 * Creates a check box with an icon and specifies whether
110 * or not it is initially selected.
111 *
112 * @param icon the Icon image to display
113 * @param selected a boolean value indicating the initial selection
114 * state. If <code>true</code> the check box is selected
115 */
116 public JCheckBox(Icon icon, boolean selected) {
117 this(null, icon, selected);
118 }
119
120 /**
121 * Creates an initially unselected check box with text.
122 *
123 * @param text the text of the check box.
124 */
125 public JCheckBox (String text) {
126 this(text, null, false);
127 }
128
129 /**
130 * Creates a check box where properties are taken from the
131 * Action supplied.
132 *
133 * @since 1.3
134 */
135 public JCheckBox(Action a) {
136 this();
137 setAction(a);
138 }
139
140
141 /**
142 * Creates a check box with text and specifies whether
143 * or not it is initially selected.
144 *
145 * @param text the text of the check box.
146 * @param selected a boolean value indicating the initial selection
147 * state. If <code>true</code> the check box is selected
148 */
149 public JCheckBox (String text, boolean selected) {
150 this(text, null, selected);
151 }
152
153 /**
154 * Creates an initially unselected check box with
155 * the specified text and icon.
156 *
157 * @param text the text of the check box.
158 * @param icon the Icon image to display
159 */
160 public JCheckBox(String text, Icon icon) {
161 this(text, icon, false);
162 }
163
164 /**
165 * Creates a check box with text and icon,
166 * and specifies whether or not it is initially selected.
167 *
168 * @param text the text of the check box.
169 * @param icon the Icon image to display
170 * @param selected a boolean value indicating the initial selection
171 * state. If <code>true</code> the check box is selected
172 */
173 public JCheckBox (String text, Icon icon, boolean selected) {
174 super(text, icon, selected);
175 setUIProperty("borderPainted", Boolean.FALSE);
176 setHorizontalAlignment(LEADING);
177 }
178
179 /**
180 * Sets the <code>borderPaintedFlat</code> property,
181 * which gives a hint to the look and feel as to the
182 * appearance of the check box border.
183 * This is usually set to <code>true</code> when a
184 * <code>JCheckBox</code> instance is used as a
185 * renderer in a component such as a <code>JTable</code> or
186 * <code>JTree</code>. The default value for the
187 * <code>borderPaintedFlat</code> property is <code>false</code>.
188 * This method fires a property changed event.
189 * Some look and feels might not implement flat borders;
190 * they will ignore this property.
191 *
192 * @param b <code>true</code> requests that the border be painted flat;
193 * <code>false</code> requests normal borders
194 * @see #isBorderPaintedFlat
195 * @beaninfo
196 * bound: true
197 * attribute: visualUpdate true
198 * description: Whether the border is painted flat.
199 * @since 1.3
200 */
201 public void setBorderPaintedFlat(boolean b) {
202 boolean oldValue = flat;
203 flat = b;
204 firePropertyChange(BORDER_PAINTED_FLAT_CHANGED_PROPERTY, oldValue, flat);
205 if (b != oldValue) {
206 revalidate();
207 repaint();
208 }
209 }
210
211 /**
212 * Gets the value of the <code>borderPaintedFlat</code> property.
213 *
214 * @return the value of the <code>borderPaintedFlat</code> property
215 * @see #setBorderPaintedFlat
216 * @since 1.3
217 */
218 public boolean isBorderPaintedFlat() {
219 return flat;
220 }
221
222 /**
223 * Resets the UI property to a value from the current look and feel.
224 *
225 * @see JComponent#updateUI
226 */
227 public void updateUI() {
228 setUI((ButtonUI)UIManager.getUI(this));
229 }
230
231
232 /**
233 * Returns a string that specifies the name of the L&F class
234 * that renders this component.
235 *
236 * @return the string "CheckBoxUI"
237 * @see JComponent#getUIClassID
238 * @see UIDefaults#getUI
239 * @beaninfo
240 * expert: true
241 * description: A string that specifies the name of the L&F class
242 */
243 public String getUIClassID() {
244 return uiClassID;
245 }
246
247
248 /**
249 * The icon for checkboxs comes from the look and feel,
250 * not the Action; this is overriden to do nothing.
251 */
252 void setIconFromAction(Action a) {
253 }
254
255 /*
256 * See readObject and writeObject in JComponent for more
257 * information about serialization in Swing.
258 */
259 private void writeObject(ObjectOutputStream s) throws IOException {
260 s.defaultWriteObject();
261 if (getUIClassID().equals(uiClassID)) {
262 byte count = JComponent.getWriteObjCounter(this);
263 JComponent.setWriteObjCounter(this, --count);
264 if (count == 0 && ui != null) {
265 ui.installUI(this);
266 }
267 }
268 }
269
270
271 /**
272 * See JComponent.readObject() for information about serialization
273 * in Swing.
274 */
275 private void readObject(ObjectInputStream s)
276 throws IOException, ClassNotFoundException
277 {
278 s.defaultReadObject();
279 if (getUIClassID().equals(uiClassID)) {
280 updateUI();
281 }
282 }
283
284
285 /**
286 * Returns a string representation of this JCheckBox. This method
287 * is intended to be used only for debugging purposes, and the
288 * content and format of the returned string may vary between
289 * implementations. The returned string may be empty but may not
290 * be <code>null</code>.
291 * specific new aspects of the JFC components.
292 *
293 * @return a string representation of this JCheckBox.
294 */
295 protected String paramString() {
296 return super.paramString();
297 }
298
299 /////////////////
300 // Accessibility support
301 ////////////////
302
303 /**
304 * Gets the AccessibleContext associated with this JCheckBox.
305 * For JCheckBoxes, the AccessibleContext takes the form of an
306 * AccessibleJCheckBox.
307 * A new AccessibleJCheckBox instance is created if necessary.
308 *
309 * @return an AccessibleJCheckBox that serves as the
310 * AccessibleContext of this JCheckBox
311 * @beaninfo
312 * expert: true
313 * description: The AccessibleContext associated with this CheckBox.
314 */
315 public AccessibleContext getAccessibleContext() {
316 if (accessibleContext == null) {
317 accessibleContext = new AccessibleJCheckBox();
318 }
319 return accessibleContext;
320 }
321
322 /**
323 * This class implements accessibility support for the
324 * <code>JCheckBox</code> class. It provides an implementation of the
325 * Java Accessibility API appropriate to check box user-interface
326 * elements.
327 * <p>
328 * <strong>Warning:</strong>
329 * Serialized objects of this class will not be compatible with
330 * future Swing releases. The current serialization support is
331 * appropriate for short term storage or RMI between applications running
332 * the same version of Swing. As of 1.4, support for long term storage
333 * of all JavaBeans<sup><font size="-2">TM</font></sup>
334 * has been added to the <code>java.beans</code> package.
335 * Please see {@link java.beans.XMLEncoder}.
336 */
337 protected class AccessibleJCheckBox extends AccessibleJToggleButton {
338
339 /**
340 * Get the role of this object.
341 *
342 * @return an instance of AccessibleRole describing the role of the object
343 * @see AccessibleRole
344 */
345 public AccessibleRole getAccessibleRole() {
346 return AccessibleRole.CHECK_BOX;
347 }
348
349 } // inner class AccessibleJCheckBox
350 }