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.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™
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 @SuppressWarnings("serial") // Same-version serialization only
79 public class JCheckBox extends JToggleButton implements Accessible {
80
81 /** Identifies a change to the flat property. */
82 public static final String BORDER_PAINTED_FLAT_CHANGED_PROPERTY = "borderPaintedFlat";
83
84 private boolean flat = false;
85
86 /**
87 * @see #getUIClassID
88 * @see #readObject
89 */
90 private static final String uiClassID = "CheckBoxUI";
91
92
93 /**
94 * Creates an initially unselected check box button with no text, no icon.
95 */
96 public JCheckBox () {
97 this(null, null, false);
98 }
99
100 /**
101 * Creates an initially unselected check box with an icon.
102 *
103 * @param icon the Icon image to display
104 */
105 public JCheckBox(Icon icon) {
106 this(null, icon, false);
107 }
108
109 /**
110 * Creates a check box with an icon and specifies whether
111 * or not it is initially selected.
112 *
113 * @param icon the Icon image to display
114 * @param selected a boolean value indicating the initial selection
115 * state. If <code>true</code> the check box is selected
116 */
117 public JCheckBox(Icon icon, boolean selected) {
118 this(null, icon, selected);
119 }
120
121 /**
122 * Creates an initially unselected check box with text.
123 *
124 * @param text the text of the check box.
125 */
126 public JCheckBox (String text) {
127 this(text, null, false);
128 }
129
130 /**
131 * Creates a check box where properties are taken from the
132 * Action supplied.
133 *
134 * @since 1.3
135 */
136 public JCheckBox(Action a) {
137 this();
138 setAction(a);
139 }
140
141
142 /**
143 * Creates a check box with text and specifies whether
144 * or not it is initially selected.
145 *
146 * @param text the text of the check box.
147 * @param selected a boolean value indicating the initial selection
148 * state. If <code>true</code> the check box is selected
149 */
150 public JCheckBox (String text, boolean selected) {
151 this(text, null, selected);
152 }
153
154 /**
155 * Creates an initially unselected check box with
156 * the specified text and icon.
157 *
158 * @param text the text of the check box.
159 * @param icon the Icon image to display
160 */
161 public JCheckBox(String text, Icon icon) {
162 this(text, icon, false);
163 }
164
165 /**
166 * Creates a check box with text and icon,
167 * and specifies whether or not it is initially selected.
168 *
169 * @param text the text of the check box.
170 * @param icon the Icon image to display
171 * @param selected a boolean value indicating the initial selection
172 * state. If <code>true</code> the check box is selected
173 */
174 public JCheckBox (String text, Icon icon, boolean selected) {
175 super(text, icon, selected);
176 setUIProperty("borderPainted", Boolean.FALSE);
177 setHorizontalAlignment(LEADING);
178 }
179
180 /**
181 * Sets the <code>borderPaintedFlat</code> property,
182 * which gives a hint to the look and feel as to the
183 * appearance of the check box border.
184 * This is usually set to <code>true</code> when a
185 * <code>JCheckBox</code> instance is used as a
186 * renderer in a component such as a <code>JTable</code> or
187 * <code>JTree</code>. The default value for the
188 * <code>borderPaintedFlat</code> property is <code>false</code>.
189 * This method fires a property changed event.
190 * Some look and feels might not implement flat borders;
191 * they will ignore this property.
192 *
193 * @param b <code>true</code> requests that the border be painted flat;
194 * <code>false</code> requests normal borders
195 * @see #isBorderPaintedFlat
196 * @beaninfo
197 * bound: true
198 * attribute: visualUpdate true
199 * description: Whether the border is painted flat.
200 * @since 1.3
201 */
202 public void setBorderPaintedFlat(boolean b) {
203 boolean oldValue = flat;
204 flat = b;
205 firePropertyChange(BORDER_PAINTED_FLAT_CHANGED_PROPERTY, oldValue, flat);
206 if (b != oldValue) {
207 revalidate();
208 repaint();
209 }
210 }
211
212 /**
213 * Gets the value of the <code>borderPaintedFlat</code> property.
214 *
215 * @return the value of the <code>borderPaintedFlat</code> property
216 * @see #setBorderPaintedFlat
217 * @since 1.3
218 */
219 public boolean isBorderPaintedFlat() {
220 return flat;
221 }
222
223 /**
224 * Resets the UI property to a value from the current look and feel.
225 *
226 * @see JComponent#updateUI
227 */
228 public void updateUI() {
229 setUI((ButtonUI)UIManager.getUI(this));
230 }
231
232
233 /**
234 * Returns a string that specifies the name of the L&F class
235 * that renders this component.
236 *
237 * @return the string "CheckBoxUI"
238 * @see JComponent#getUIClassID
239 * @see UIDefaults#getUI
240 * @beaninfo
241 * expert: true
242 * description: A string that specifies the name of the L&F class
243 */
244 public String getUIClassID() {
245 return uiClassID;
246 }
247
248
249 /**
250 * The icon for checkboxs comes from the look and feel,
251 * not the Action; this is overriden to do nothing.
252 */
253 void setIconFromAction(Action a) {
254 }
255
256 /*
257 * See readObject and writeObject in JComponent for more
258 * information about serialization in Swing.
259 */
260 private void writeObject(ObjectOutputStream s) throws IOException {
261 s.defaultWriteObject();
262 if (getUIClassID().equals(uiClassID)) {
263 byte count = JComponent.getWriteObjCounter(this);
264 JComponent.setWriteObjCounter(this, --count);
265 if (count == 0 && ui != null) {
266 ui.installUI(this);
267 }
268 }
269 }
270
271
272 /**
273 * See JComponent.readObject() for information about serialization
274 * in Swing.
275 */
276 private void readObject(ObjectInputStream s)
277 throws IOException, ClassNotFoundException
278 {
279 s.defaultReadObject();
280 if (getUIClassID().equals(uiClassID)) {
281 updateUI();
282 }
283 }
284
285
286 /**
287 * Returns a string representation of this JCheckBox. This method
288 * is intended to be used only for debugging purposes, and the
289 * content and format of the returned string may vary between
290 * implementations. The returned string may be empty but may not
291 * be <code>null</code>.
292 * specific new aspects of the JFC components.
293 *
294 * @return a string representation of this JCheckBox.
295 */
296 protected String paramString() {
297 return super.paramString();
298 }
299
300 /////////////////
301 // Accessibility support
302 ////////////////
303
304 /**
305 * Gets the AccessibleContext associated with this JCheckBox.
306 * For JCheckBoxes, the AccessibleContext takes the form of an
307 * AccessibleJCheckBox.
308 * A new AccessibleJCheckBox instance is created if necessary.
309 *
310 * @return an AccessibleJCheckBox that serves as the
311 * AccessibleContext of this JCheckBox
312 * @beaninfo
313 * expert: true
314 * description: The AccessibleContext associated with this CheckBox.
315 */
316 public AccessibleContext getAccessibleContext() {
317 if (accessibleContext == null) {
318 accessibleContext = new AccessibleJCheckBox();
319 }
320 return accessibleContext;
321 }
322
323 /**
324 * This class implements accessibility support for the
325 * <code>JCheckBox</code> class. It provides an implementation of the
326 * Java Accessibility API appropriate to check box user-interface
327 * elements.
328 * <p>
329 * <strong>Warning:</strong>
330 * Serialized objects of this class will not be compatible with
331 * future Swing releases. The current serialization support is
332 * appropriate for short term storage or RMI between applications running
333 * the same version of Swing. As of 1.4, support for long term storage
334 * of all JavaBeans™
335 * has been added to the <code>java.beans</code> package.
336 * Please see {@link java.beans.XMLEncoder}.
337 */
338 @SuppressWarnings("serial") // Same-version serialization only
339 protected class AccessibleJCheckBox extends AccessibleJToggleButton {
340
341 /**
342 * Get the role of this object.
343 *
344 * @return an instance of AccessibleRole describing the role of the object
345 * @see AccessibleRole
346 */
347 public AccessibleRole getAccessibleRole() {
348 return AccessibleRole.CHECK_BOX;
349 }
350
351 } // inner class AccessibleJCheckBox
352 }