1 /*
2 * Copyright (c) 1997, 2015, 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 java.io.ObjectOutputStream;
31 import java.io.IOException;
32
33 import javax.accessibility.*;
34
35 /**
36 * A menu item that can be selected or deselected. If selected, the menu
37 * item typically appears with a checkmark next to it. If unselected or
38 * deselected, the menu item appears without a checkmark. Like a regular
39 * menu item, a check box menu item can have either text or a graphic
40 * icon associated with it, or both.
41 * <p>
42 * Either <code>isSelected</code>/<code>setSelected</code> or
43 * <code>getState</code>/<code>setState</code> can be used
44 * to determine/specify the menu item's selection state. The
45 * preferred methods are <code>isSelected</code> and
46 * <code>setSelected</code>, which work for all menus and buttons.
47 * The <code>getState</code> and <code>setState</code> methods exist for
48 * compatibility with other component sets.
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="https://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 * Some times it is required to select several check box menu items from a menu.
60 * In this case it is useful that clicking on one check box menu item does not
61 * close the menu. Such behavior can be controlled either by client
62 * {@link JComponent#putClientProperty} or the Look and Feel
63 * {@link UIManager#put} property named
64 * {@code "CheckBoxMenuItem.doNotCloseOnMouseClick"}. The default value is
65 * {@code false}. Setting the property to {@code true} prevents the menu from
66 * closing when it is clicked by the mouse. If the client property is set its
67 * value is always used; otherwise the {@literal L&F} property is queried.
68 * Note: some {@code L&F}s may ignore this property. All built-in {@code L&F}s
69 * inherit this behaviour.
70 * <p>
71 * For further information and examples of using check box menu items,
72 * see <a
73 href="https://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
74 * a section in <em>The Java Tutorial.</em>
75 * <p>
76 * <strong>Warning:</strong> Swing is not thread safe. For more
77 * information see <a
78 * href="package-summary.html#threading">Swing's Threading
79 * Policy</a>.
80 * <p>
81 * <strong>Warning:</strong>
82 * Serialized objects of this class will not be compatible with
83 * future Swing releases. The current serialization support is
84 * appropriate for short term storage or RMI between applications running
85 * the same version of Swing. As of 1.4, support for long term storage
86 * of all JavaBeans™
87 * has been added to the <code>java.beans</code> package.
88 * Please see {@link java.beans.XMLEncoder}.
89 *
90 * @author Georges Saab
91 * @author David Karlton
92 * @since 1.2
93 */
94 @JavaBean(description = "A menu item which can be selected or deselected.")
95 @SwingContainer(false)
96 @SuppressWarnings("serial") // Same-version serialization only
97 public class JCheckBoxMenuItem extends JMenuItem implements SwingConstants,
98 Accessible
99 {
100 /**
101 * @see #getUIClassID
102 * @see #readObject
103 */
104 private static final String uiClassID = "CheckBoxMenuItemUI";
105
106 /**
107 * Creates an initially unselected check box menu item with no set text or icon.
108 */
109 public JCheckBoxMenuItem() {
110 this(null, null, false);
111 }
112
113 /**
114 * Creates an initially unselected check box menu item with an icon.
115 *
116 * @param icon the icon of the {@code JCheckBoxMenuItem}.
117 */
118 public JCheckBoxMenuItem(Icon icon) {
119 this(null, icon, false);
120 }
121
122 /**
123 * Creates an initially unselected check box menu item with text.
124 *
125 * @param text the text of the {@code JCheckBoxMenuItem}
126 */
127 public JCheckBoxMenuItem(String text) {
128 this(text, null, false);
129 }
130
131 /**
132 * Creates a menu item whose properties are taken from the
133 * Action supplied.
134 *
135 * @param a the action of the {@code JCheckBoxMenuItem}
136 * @since 1.3
137 */
138 public JCheckBoxMenuItem(Action a) {
139 this();
140 setAction(a);
141 }
142
143 /**
144 * Creates an initially unselected check box menu item with the specified text and icon.
145 *
146 * @param text the text of the {@code JCheckBoxMenuItem}
147 * @param icon the icon of the {@code JCheckBoxMenuItem}
148 */
149 public JCheckBoxMenuItem(String text, Icon icon) {
150 this(text, icon, false);
151 }
152
153 /**
154 * Creates a check box menu item with the specified text and selection state.
155 *
156 * @param text the text of the check box menu item.
157 * @param b the selected state of the check box menu item
158 */
159 public JCheckBoxMenuItem(String text, boolean b) {
160 this(text, null, b);
161 }
162
163 /**
164 * Creates a check box menu item with the specified text, icon, and selection state.
165 *
166 * @param text the text of the check box menu item
167 * @param icon the icon of the check box menu item
168 * @param b the selected state of the check box menu item
169 */
170 public JCheckBoxMenuItem(String text, Icon icon, boolean b) {
171 super(text, icon);
172 setModel(new JToggleButton.ToggleButtonModel());
173 setSelected(b);
174 setFocusable(false);
175 }
176
177 /**
178 * Returns the name of the L&F class
179 * that renders this component.
180 *
181 * @return the string "CheckBoxMenuItemUI"
182 * @see JComponent#getUIClassID
183 * @see UIDefaults#getUI
184 */
185 @BeanProperty(bound = false)
186 public String getUIClassID() {
187 return uiClassID;
188 }
189
190 /**
191 * Returns the selected-state of the item. This method
192 * exists for AWT compatibility only. New code should
193 * use isSelected() instead.
194 *
195 * @return true if the item is selected
196 */
197 public boolean getState() {
198 return isSelected();
199 }
200
201 /**
202 * Sets the selected-state of the item. This method
203 * exists for AWT compatibility only. New code should
204 * use setSelected() instead.
205 *
206 * @param b a boolean value indicating the item's
207 * selected-state, where true=selected
208 */
209 @BeanProperty(bound = false, hidden = true, description
210 = "The selection state of the check box menu item")
211 public synchronized void setState(boolean b) {
212 setSelected(b);
213 }
214
215
216 /**
217 * Returns an array (length 1) containing the check box menu item
218 * label or null if the check box is not selected.
219 *
220 * @return an array containing one Object -- the text of the menu item
221 * -- if the item is selected; otherwise null
222 */
223 @BeanProperty(bound = false)
224 public Object[] getSelectedObjects() {
225 if (isSelected() == false)
226 return null;
227 Object[] selectedObjects = new Object[1];
228 selectedObjects[0] = getText();
229 return selectedObjects;
230 }
231
232 /**
233 * See readObject() and writeObject() in JComponent for more
234 * information about serialization in Swing.
235 */
236 private void writeObject(ObjectOutputStream s) throws IOException {
237 s.defaultWriteObject();
238 if (getUIClassID().equals(uiClassID)) {
239 byte count = JComponent.getWriteObjCounter(this);
240 JComponent.setWriteObjCounter(this, --count);
241 if (count == 0 && ui != null) {
242 ui.installUI(this);
243 }
244 }
245 }
246
247
248 /**
249 * Returns a string representation of this JCheckBoxMenuItem. This method
250 * is intended to be used only for debugging purposes, and the
251 * content and format of the returned string may vary between
252 * implementations. The returned string may be empty but may not
253 * be <code>null</code>.
254 *
255 * @return a string representation of this JCheckBoxMenuItem.
256 */
257 protected String paramString() {
258 return super.paramString();
259 }
260
261 /**
262 * Overriden to return true, JCheckBoxMenuItem supports
263 * the selected state.
264 */
265 boolean shouldUpdateSelectedStateFromAction() {
266 return true;
267 }
268
269 /////////////////
270 // Accessibility support
271 ////////////////
272
273 /**
274 * Gets the AccessibleContext associated with this JCheckBoxMenuItem.
275 * For JCheckBoxMenuItems, the AccessibleContext takes the form of an
276 * AccessibleJCheckBoxMenuItem.
277 * A new AccessibleJCheckBoxMenuItem instance is created if necessary.
278 *
279 * @return an AccessibleJCheckBoxMenuItem that serves as the
280 * AccessibleContext of this AccessibleJCheckBoxMenuItem
281 */
282 @BeanProperty(bound = false)
283 public AccessibleContext getAccessibleContext() {
284 if (accessibleContext == null) {
285 accessibleContext = new AccessibleJCheckBoxMenuItem();
286 }
287 return accessibleContext;
288 }
289
290 /**
291 * This class implements accessibility support for the
292 * <code>JCheckBoxMenuItem</code> class. It provides an implementation
293 * of the Java Accessibility API appropriate to checkbox menu item
294 * user-interface elements.
295 * <p>
296 * <strong>Warning:</strong>
297 * Serialized objects of this class will not be compatible with
298 * future Swing releases. The current serialization support is
299 * appropriate for short term storage or RMI between applications running
300 * the same version of Swing. As of 1.4, support for long term storage
301 * of all JavaBeans™
302 * has been added to the <code>java.beans</code> package.
303 * Please see {@link java.beans.XMLEncoder}.
304 */
305 @SuppressWarnings("serial") // Same-version serialization only
306 protected class AccessibleJCheckBoxMenuItem extends AccessibleJMenuItem {
307 /**
308 * Get the role of this object.
309 *
310 * @return an instance of AccessibleRole describing the role of the
311 * object
312 */
313 public AccessibleRole getAccessibleRole() {
314 return AccessibleRole.CHECK_BOX;
315 }
316 } // inner class AccessibleJCheckBoxMenuItem
317 }