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 * @since 1.2
78 */
79 @SuppressWarnings("serial") // Same-version serialization only
80 public class JCheckBox extends JToggleButton implements Accessible {
81
82 /** Identifies a change to the flat property. */
83 public static final String BORDER_PAINTED_FLAT_CHANGED_PROPERTY = "borderPaintedFlat";
84
85 private boolean flat = false;
86
87 /**
88 * @see #getUIClassID
89 * @see #readObject
90 */
91 private static final String uiClassID = "CheckBoxUI";
92
93
94 /**
95 * Creates an initially unselected check box button with no text, no icon.
96 */
97 public JCheckBox () {
98 this(null, null, false);
99 }
100
101 /**
102 * Creates an initially unselected check box with an icon.
103 *
104 * @param icon the Icon image to display
105 */
106 public JCheckBox(Icon icon) {
107 this(null, icon, false);
108 }
109
110 /**
111 * Creates a check box with an icon and specifies whether
112 * or not it is initially selected.
113 *
114 * @param icon the Icon image to display
115 * @param selected a boolean value indicating the initial selection
116 * state. If <code>true</code> the check box is selected
117 */
118 public JCheckBox(Icon icon, boolean selected) {
119 this(null, icon, selected);
120 }
121
122 /**
123 * Creates an initially unselected check box with text.
124 *
125 * @param text the text of the check box.
126 */
127 public JCheckBox (String text) {
128 this(text, null, false);
129 }
130
131 /**
132 * Creates a check box where properties are taken from the
133 * Action supplied.
134 *
135 * @param a the {@code Action} used to specify the new check box
136 * @since 1.3
137 */
138 public JCheckBox(Action a) {
139 this();
140 setAction(a);
141 }
142
143
144 /**
145 * Creates a check box with text and specifies whether
146 * or not it is initially selected.
147 *
148 * @param text the text of the check box.
149 * @param selected a boolean value indicating the initial selection
150 * state. If <code>true</code> the check box is selected
151 */
152 public JCheckBox (String text, boolean selected) {
153 this(text, null, selected);
154 }
155
156 /**
157 * Creates an initially unselected check box with
158 * the specified text and icon.
159 *
160 * @param text the text of the check box.
161 * @param icon the Icon image to display
162 */
163 public JCheckBox(String text, Icon icon) {
164 this(text, icon, false);
165 }
166
167 /**
168 * Creates a check box with text and icon,
169 * and specifies whether or not it is initially selected.
170 *
171 * @param text the text of the check box.
172 * @param icon the Icon image to display
173 * @param selected a boolean value indicating the initial selection
174 * state. If <code>true</code> the check box is selected
175 */
176 public JCheckBox (String text, Icon icon, boolean selected) {
177 super(text, icon, selected);
178 setUIProperty("borderPainted", Boolean.FALSE);
179 setHorizontalAlignment(LEADING);
180 }
181
182 /**
183 * Sets the <code>borderPaintedFlat</code> property,
184 * which gives a hint to the look and feel as to the
185 * appearance of the check box border.
186 * This is usually set to <code>true</code> when a
187 * <code>JCheckBox</code> instance is used as a
188 * renderer in a component such as a <code>JTable</code> or
189 * <code>JTree</code>. The default value for the
190 * <code>borderPaintedFlat</code> property is <code>false</code>.
191 * This method fires a property changed event.
192 * Some look and feels might not implement flat borders;
193 * they will ignore this property.
194 *
195 * @param b <code>true</code> requests that the border be painted flat;
196 * <code>false</code> requests normal borders
197 * @see #isBorderPaintedFlat
198 * @beaninfo
199 * bound: true
200 * attribute: visualUpdate true
201 * description: Whether the border is painted flat.
202 * @since 1.3
203 */
204 public void setBorderPaintedFlat(boolean b) {
205 boolean oldValue = flat;
206 flat = b;
207 firePropertyChange(BORDER_PAINTED_FLAT_CHANGED_PROPERTY, oldValue, flat);
208 if (b != oldValue) {
209 revalidate();
210 repaint();
211 }
212 }
213
214 /**
215 * Gets the value of the <code>borderPaintedFlat</code> property.
216 *
217 * @return the value of the <code>borderPaintedFlat</code> property
218 * @see #setBorderPaintedFlat
219 * @since 1.3
220 */
221 public boolean isBorderPaintedFlat() {
222 return flat;
223 }
224
225 /**
226 * Resets the UI property to a value from the current look and feel.
227 *
228 * @see JComponent#updateUI
229 */
230 public void updateUI() {
231 setUI((ButtonUI)UIManager.getUI(this));
232 }
233
234
235 /**
236 * Returns a string that specifies the name of the L&F class
237 * that renders this component.
238 *
239 * @return the string "CheckBoxUI"
240 * @see JComponent#getUIClassID
241 * @see UIDefaults#getUI
242 * @beaninfo
243 * expert: true
244 * description: A string that specifies the name of the L&F class
245 */
246 public String getUIClassID() {
247 return uiClassID;
248 }
249
250
251 /**
252 * The icon for checkboxs comes from the look and feel,
253 * not the Action; this is overriden to do nothing.
254 */
255 void setIconFromAction(Action a) {
256 }
257
258 /*
259 * See readObject and writeObject in JComponent for more
260 * information about serialization in Swing.
261 */
262 private void writeObject(ObjectOutputStream s) throws IOException {
263 s.defaultWriteObject();
264 if (getUIClassID().equals(uiClassID)) {
265 byte count = JComponent.getWriteObjCounter(this);
266 JComponent.setWriteObjCounter(this, --count);
267 if (count == 0 && ui != null) {
268 ui.installUI(this);
269 }
270 }
271 }
272
273
274 /**
275 * See JComponent.readObject() for information about serialization
276 * in Swing.
277 */
278 private void readObject(ObjectInputStream s)
279 throws IOException, ClassNotFoundException
280 {
281 s.defaultReadObject();
282 if (getUIClassID().equals(uiClassID)) {
283 updateUI();
284 }
285 }
286
287
288 /**
289 * Returns a string representation of this JCheckBox. This method
290 * is intended to be used only for debugging purposes, and the
291 * content and format of the returned string may vary between
292 * implementations. The returned string may be empty but may not
293 * be <code>null</code>.
294 * specific new aspects of the JFC components.
295 *
296 * @return a string representation of this JCheckBox.
297 */
298 protected String paramString() {
299 return super.paramString();
300 }
301
302 /////////////////
303 // Accessibility support
304 ////////////////
305
306 /**
307 * Gets the AccessibleContext associated with this JCheckBox.
308 * For JCheckBoxes, the AccessibleContext takes the form of an
309 * AccessibleJCheckBox.
310 * A new AccessibleJCheckBox instance is created if necessary.
311 *
312 * @return an AccessibleJCheckBox that serves as the
313 * AccessibleContext of this JCheckBox
314 * @beaninfo
315 * expert: true
316 * description: The AccessibleContext associated with this CheckBox.
317 */
318 public AccessibleContext getAccessibleContext() {
319 if (accessibleContext == null) {
320 accessibleContext = new AccessibleJCheckBox();
321 }
322 return accessibleContext;
323 }
324
325 /**
326 * This class implements accessibility support for the
327 * <code>JCheckBox</code> class. It provides an implementation of the
328 * Java Accessibility API appropriate to check box user-interface
329 * elements.
330 * <p>
331 * <strong>Warning:</strong>
332 * Serialized objects of this class will not be compatible with
333 * future Swing releases. The current serialization support is
334 * appropriate for short term storage or RMI between applications running
335 * the same version of Swing. As of 1.4, support for long term storage
336 * of all JavaBeans™
337 * has been added to the <code>java.beans</code> package.
338 * Please see {@link java.beans.XMLEncoder}.
339 */
340 @SuppressWarnings("serial") // Same-version serialization only
341 protected class AccessibleJCheckBox extends AccessibleJToggleButton {
342
343 /**
344 * Get the role of this object.
345 *
346 * @return an instance of AccessibleRole describing the role of the object
347 * @see AccessibleRole
348 */
349 public AccessibleRole getAccessibleRole() {
350 return AccessibleRole.CHECK_BOX;
351 }
352
353 } // inner class AccessibleJCheckBox
354 }