1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
4 *
5 *
6 *
7 *
8 *
9 *
10 *
11 *
12 *
13 *
14 *
15 *
16 *
17 *
18 *
19 *
20 *
21 *
22 *
23 *
24 */
25 package javax.swing;
26
27 import java.beans.ConstructorProperties;
28
29 import java.awt.*;
30 import java.awt.event.*;
31 import java.awt.image.*;
32
33 import javax.swing.plaf.*;
34 import javax.swing.event.*;
35 import javax.accessibility.*;
36
37 import java.io.ObjectOutputStream;
38 import java.io.ObjectInputStream;
39 import java.io.IOException;
40
41
42 /**
43 * An implementation of a "push" button.
44 * <p>
45 * Buttons can be configured, and to some degree controlled, by
46 * <code><a href="Action.html">Action</a></code>s. Using an
47 * <code>Action</code> with a button has many benefits beyond directly
48 * configuring a button. Refer to <a href="Action.html#buttonActions">
49 * Swing Components Supporting <code>Action</code></a> for more
50 * details, and you can find more information in <a
51 * href="https://docs.oracle.com/javase/tutorial/uiswing/misc/action.html">How
52 * to Use Actions</a>, a section in <em>The Java Tutorial</em>.
53 * <p>
54 * See <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/button.html">How to Use Buttons, Check Boxes, and Radio Buttons</a>
55 * in <em>The Java Tutorial</em>
56 * for information and examples of using buttons.
57 * <p>
58 * <strong>Warning:</strong> Swing is not thread safe. For more
59 * information see <a
60 * href="package-summary.html#threading">Swing's Threading
61 * Policy</a>.
62 * <p>
63 * <strong>Warning:</strong>
64 * Serialized objects of this class will not be compatible with
65 * future Swing releases. The current serialization support is
66 * appropriate for short term storage or RMI between applications running
67 * the same version of Swing. As of 1.4, support for long term storage
68 * of all JavaBeans™
69 * has been added to the <code>java.beans</code> package.
70 * Please see {@link java.beans.XMLEncoder}.
71 *
72 * @beaninfo
73 * attribute: isContainer false
74 * description: An implementation of a \"push\" button.
75 *
76 * @author Jeff Dinkins
77 */
78 @SuppressWarnings("serial")
79 public class JButton extends AbstractButton implements Accessible {
80
81 /**
82 * @see #getUIClassID
83 * @see #readObject
84 */
85 private static final String uiClassID = "ButtonUI";
86
87 /**
88 * Creates a button with no set text or icon.
89 */
90 public JButton() {
91 this(null, null);
92 }
93
94 /**
95 * Creates a button with an icon.
96 *
97 * @param icon the Icon image to display on the button
98 */
99 public JButton(Icon icon) {
100 this(null, icon);
101 }
102
103 /**
104 * Creates a button with text.
105 *
106 * @param text the text of the button
107 */
108 @ConstructorProperties({"text"})
109 public JButton(String text) {
110 this(text, null);
111 }
112
113 /**
114 * Creates a button where properties are taken from the
115 * <code>Action</code> supplied.
116 *
117 * @param a the <code>Action</code> used to specify the new button
118 *
119 * @since 1.3
120 */
121 public JButton(Action a) {
122 this();
123 setAction(a);
124 }
125
126 /**
127 * Creates a button with initial text and an icon.
128 *
129 * @param text the text of the button
130 * @param icon the Icon image to display on the button
131 */
132 public JButton(String text, Icon icon) {
133 // Create the model
134 setModel(new DefaultButtonModel());
135
136 // initialize
137 init(text, icon);
138 }
139
140 /**
141 * Resets the UI property to a value from the current look and
142 * feel.
143 *
144 * @see JComponent#updateUI
145 */
146 public void updateUI() {
147 setUI((ButtonUI)UIManager.getUI(this));
148 }
149
150
151 /**
152 * Returns a string that specifies the name of the L&F class
153 * that renders this component.
154 *
155 * @return the string "ButtonUI"
156 * @see JComponent#getUIClassID
157 * @see UIDefaults#getUI
158 * @beaninfo
159 * expert: true
160 * description: A string that specifies the name of the L&F class.
161 */
162 public String getUIClassID() {
163 return uiClassID;
164 }
165
166
167 /**
168 * Gets the value of the <code>defaultButton</code> property,
169 * which if <code>true</code> means that this button is the current
170 * default button for its <code>JRootPane</code>.
171 * Most look and feels render the default button
172 * differently, and may potentially provide bindings
173 * to access the default button.
174 *
175 * @return the value of the <code>defaultButton</code> property
176 * @see JRootPane#setDefaultButton
177 * @see #isDefaultCapable
178 * @beaninfo
179 * description: Whether or not this button is the default button
180 */
181 public boolean isDefaultButton() {
182 JRootPane root = SwingUtilities.getRootPane(this);
183 if (root != null) {
184 return root.getDefaultButton() == this;
185 }
186 return false;
187 }
188
189 /**
190 * Gets the value of the <code>defaultCapable</code> property.
191 *
192 * @return the value of the <code>defaultCapable</code> property
193 * @see #setDefaultCapable
194 * @see #isDefaultButton
195 * @see JRootPane#setDefaultButton
196 */
197 public boolean isDefaultCapable() {
198 return defaultCapable;
199 }
200
201 /**
202 * Sets the <code>defaultCapable</code> property,
203 * which determines whether this button can be
204 * made the default button for its root pane.
205 * The default value of the <code>defaultCapable</code>
206 * property is <code>true</code> unless otherwise
207 * specified by the look and feel.
208 *
209 * @param defaultCapable <code>true</code> if this button will be
210 * capable of being the default button on the
211 * <code>RootPane</code>; otherwise <code>false</code>
212 * @see #isDefaultCapable
213 * @beaninfo
214 * bound: true
215 * attribute: visualUpdate true
216 * description: Whether or not this button can be the default button
217 */
218 public void setDefaultCapable(boolean defaultCapable) {
219 boolean oldDefaultCapable = this.defaultCapable;
220 this.defaultCapable = defaultCapable;
221 firePropertyChange("defaultCapable", oldDefaultCapable, defaultCapable);
222 }
223
224 /**
225 * Overrides <code>JComponent.removeNotify</code> to check if
226 * this button is currently set as the default button on the
227 * <code>RootPane</code>, and if so, sets the <code>RootPane</code>'s
228 * default button to <code>null</code> to ensure the
229 * <code>RootPane</code> doesn't hold onto an invalid button reference.
230 */
231 public void removeNotify() {
232 JRootPane root = SwingUtilities.getRootPane(this);
233 if (root != null && root.getDefaultButton() == this) {
234 root.setDefaultButton(null);
235 }
236 super.removeNotify();
237 }
238
239 /**
240 * See readObject() and writeObject() in JComponent for more
241 * information about serialization in Swing.
242 */
243 private void writeObject(ObjectOutputStream s) throws IOException {
244 s.defaultWriteObject();
245 if (getUIClassID().equals(uiClassID)) {
246 byte count = JComponent.getWriteObjCounter(this);
247 JComponent.setWriteObjCounter(this, --count);
248 if (count == 0 && ui != null) {
249 ui.installUI(this);
250 }
251 }
252 }
253
254
255 /**
256 * Returns a string representation of this <code>JButton</code>.
257 * This method is intended to be used only for debugging purposes, and the
258 * content and format of the returned string may vary between
259 * implementations. The returned string may be empty but may not
260 * be <code>null</code>.
261 *
262 * @return a string representation of this <code>JButton</code>
263 */
264 protected String paramString() {
265 String defaultCapableString = (defaultCapable ? "true" : "false");
266
267 return super.paramString() +
268 ",defaultCapable=" + defaultCapableString;
269 }
270
271
272 /////////////////
273 // Accessibility support
274 ////////////////
275
276 /**
277 * Gets the <code>AccessibleContext</code> associated with this
278 * <code>JButton</code>. For <code>JButton</code>s,
279 * the <code>AccessibleContext</code> takes the form of an
280 * <code>AccessibleJButton</code>.
281 * A new <code>AccessibleJButton</code> instance is created if necessary.
282 *
283 * @return an <code>AccessibleJButton</code> that serves as the
284 * <code>AccessibleContext</code> of this <code>JButton</code>
285 * @beaninfo
286 * expert: true
287 * description: The AccessibleContext associated with this Button.
288 */
289 public AccessibleContext getAccessibleContext() {
290 if (accessibleContext == null) {
291 accessibleContext = new AccessibleJButton();
292 }
293 return accessibleContext;
294 }
295
296 /**
297 * This class implements accessibility support for the
298 * <code>JButton</code> class. It provides an implementation of the
299 * Java Accessibility API appropriate to button user-interface
300 * elements.
301 * <p>
302 * <strong>Warning:</strong>
303 * Serialized objects of this class will not be compatible with
304 * future Swing releases. The current serialization support is
305 * appropriate for short term storage or RMI between applications running
306 * the same version of Swing. As of 1.4, support for long term storage
307 * of all JavaBeans™
308 * has been added to the <code>java.beans</code> package.
309 * Please see {@link java.beans.XMLEncoder}.
310 */
311 @SuppressWarnings("serial")
312 protected class AccessibleJButton extends AccessibleAbstractButton {
313
314 /**
315 * Get the role of this object.
316 *
317 * @return an instance of AccessibleRole describing the role of the
318 * object
319 * @see AccessibleRole
320 */
321 public AccessibleRole getAccessibleRole() {
322 return AccessibleRole.PUSH_BUTTON;
323 }
324 } // inner class AccessibleJButton
325 }
326