001 /* JToggleButton.java --
002 Copyright (C) 2002, 2004, 2005, 2006, Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package javax.swing;
040
041 import java.awt.event.ActionEvent;
042 import java.awt.event.ItemEvent;
043 import java.awt.event.ItemListener;
044
045 import javax.accessibility.Accessible;
046 import javax.accessibility.AccessibleContext;
047 import javax.accessibility.AccessibleRole;
048 import javax.accessibility.AccessibleState;
049 import javax.swing.plaf.ButtonUI;
050
051 /**
052 * The <code>JToggleButton</code> component provides a stateful button,
053 * which can be either selected or unselected. This provides the basis
054 * for the implementations of radio buttons (<code>JRadioButton</code>)
055 * and check boxes (<code>JCheckBox</code>).
056 *
057 * @author Michael Koch (konqueror@gmx.de)
058 * @author Graydon Hoare (graydon@redhat.com)
059 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
060 * @see JRadioButton
061 * @see JCheckBox
062 * @since 1.2
063 */
064 public class JToggleButton extends AbstractButton implements Accessible
065 {
066 /**
067 * This class provides accessibility support for the toggle button.
068 */
069 protected class AccessibleJToggleButton
070 extends AccessibleAbstractButton
071 implements ItemListener
072 {
073 private static final long serialVersionUID = -8652952712161229225L;
074
075 /**
076 * Constructor for the accessible toggle button.
077 */
078 public AccessibleJToggleButton()
079 {
080 super();
081 /* Register the accessible toggle button as a listener for item events */
082 addItemListener(this);
083 }
084
085 /**
086 * Returns the accessible role for the toggle button.
087 *
088 * @return An instance of <code>AccessibleRole</code>, describing
089 * the role of the toggle button.
090 */
091 public AccessibleRole getAccessibleRole()
092 {
093 return AccessibleRole.TOGGLE_BUTTON;
094 }
095
096 /**
097 * Monitors the toggle button for state changes and fires accessible
098 * property change events when they occur.
099 *
100 * @param event the event that occurred.
101 */
102 public void itemStateChanged(ItemEvent event)
103 {
104 /* Fire a state property change event as the button's state has changed */
105 if (event.getStateChange() == ItemEvent.SELECTED)
106 {
107 /* State has changed from unselected (null) to selected */
108 firePropertyChange(ACCESSIBLE_STATE_PROPERTY, null, AccessibleState.SELECTED);
109 }
110 else
111 {
112 /* State has changed from selected to unselected (null) */
113 firePropertyChange(ACCESSIBLE_STATE_PROPERTY, AccessibleState.ENABLED, null);
114 }
115 }
116
117 }
118
119 /**
120 * The model handles the storage and maintenance of the state of
121 * the toggle button. This follows the same paradigm (the MVC
122 * or Model-View-Controller design pattern) employed by
123 * other Swing components, where the data associated with a component
124 * is stored separately from the display aspects.
125 */
126 public static class ToggleButtonModel extends DefaultButtonModel
127 {
128 /**
129 * Compatible with Sun's JDK.
130 */
131 private static final long serialVersionUID = -1589950750899943974L;
132
133 /**
134 * Sets the pressed state of the button. The selected state
135 * of the button also changes follwing the button being pressed.
136 *
137 * @param p true if the button is pressed down.
138 */
139 public void setPressed(boolean p)
140 {
141 // cannot change PRESSED state unless button is enabled
142 if (! isEnabled())
143 return;
144
145 // if this call does not represent a CHANGE in state, then return
146 if ((p && isPressed()) || (!p && !isPressed()))
147 return;
148
149 // The JDK first fires events in the following order:
150 // 1. ChangeEvent for selected
151 // 2. ChangeEvent for pressed
152 // 3. ActionEvent
153 // So do we.
154
155 // setPressed(false) == mouse release on us,
156 // if we were armed, we flip the selected state.
157 if (!p && isArmed())
158 {
159 setSelected(! isSelected());
160 }
161
162 // make the change
163 if (p)
164 stateMask = stateMask | PRESSED;
165 else
166 stateMask = stateMask & (~PRESSED);
167
168 // notify interested ChangeListeners
169 fireStateChanged();
170
171 if (!p && isArmed())
172 {
173 fireActionPerformed(new ActionEvent(this,
174 ActionEvent.ACTION_PERFORMED,
175 actionCommand));
176 }
177 }
178
179 /**
180 * Checks if the button is selected.
181 *
182 * @return <code>true</code> if the button is selected.
183 */
184 public boolean isSelected()
185 {
186 return super.isSelected();
187 }
188
189 /**
190 * Sets the selected state of the button.
191 *
192 * @param b true if button is selected
193 */
194 public void setSelected(boolean b)
195 {
196 super.setSelected(b);
197 }
198 }
199
200 /**
201 * Compatible with Sun's JDK.
202 */
203 private static final long serialVersionUID = -3128248873429850443L;
204
205 /**
206 * Constructs an unselected toggle button with no text or icon.
207 */
208 public JToggleButton()
209 {
210 this(null, null, false);
211 }
212
213 /**
214 * Constructs a toggle button using the labelling, state
215 * and icon specified by the supplied action.
216 *
217 * @param a the action to use to define the properties of the button.
218 */
219 public JToggleButton(Action a)
220 {
221 this();
222 setAction(a);
223 }
224
225 /**
226 * Constructs an unselected toggle button with the supplied icon
227 * and no text.
228 *
229 * @param icon the icon to use.
230 */
231 public JToggleButton(Icon icon)
232 {
233 this(null, icon, false);
234 }
235
236 /**
237 * Constructs a toggle button with the supplied icon and state.
238 *
239 * @param icon the icon to use.
240 * @param selected if true, the toggle button is initially in the
241 * selected state. Otherwise, the button is unselected.
242 */
243 public JToggleButton(Icon icon, boolean selected)
244 {
245 this(null, icon, selected);
246 }
247
248 /**
249 * Constructs an unselected toggle button using the supplied text
250 * and no icon.
251 *
252 * @param text the text to use.
253 */
254 public JToggleButton(String text)
255 {
256 this(text, null, false);
257 }
258
259 /**
260 * Constructs a toggle button with the supplied text and state.
261 *
262 * @param text the text to use.
263 * @param selected if true, the toggle button is initially in the
264 * selected state. Otherwise, the button is unselected.
265 */
266 public JToggleButton(String text, boolean selected)
267 {
268 this(text, null, selected);
269 }
270
271 /**
272 * Constructs an unselected toggle button with the supplied text
273 * and icon.
274 *
275 * @param text the text to use.
276 * @param icon the icon to use.
277 */
278 public JToggleButton(String text, Icon icon)
279 {
280 this(text, icon, false);
281 }
282
283 /**
284 * Constructs a toggle button with the supplied text, icon and state.
285 *
286 * @param text the text to use.
287 * @param icon the icon to use.
288 * @param selected if true, the toggle button is initially in the
289 * selected state. Otherwise, the button is unselected.
290 */
291 public JToggleButton (String text, Icon icon, boolean selected)
292 {
293 super();
294 setModel(new ToggleButtonModel());
295 init(text, icon);
296 model.setSelected(selected);
297 setAlignmentX(LEFT_ALIGNMENT);
298 }
299
300 /**
301 * Gets the AccessibleContext associated with this <code>JToggleButton</code>.
302 * The context is created, if necessary.
303 *
304 * @return the associated context
305 */
306 public AccessibleContext getAccessibleContext()
307 {
308 /* Create the context if this is the first request */
309 if (accessibleContext == null)
310 {
311 /* Create the context */
312 accessibleContext = new AccessibleJToggleButton();
313 }
314 return accessibleContext;
315 }
316
317 /**
318 * Returns a string that specifies the name of the Look and Feel
319 * class that renders this component.
320 *
321 * @return The Look and Feel UI class in <code>String</code> form.
322 */
323 public String getUIClassID()
324 {
325 return "ToggleButtonUI";
326 }
327
328 /**
329 * Returns a textual representation of this component for debugging.
330 * Users should not depend on anything as regards the content or formatting
331 * of this string, except for the fact that the returned string may never be
332 * null (only empty).
333 *
334 * @return the component in <code>String</code> form for debugging.
335 */
336 protected String paramString()
337 {
338 return super.paramString();
339 }
340
341 /**
342 * This method resets the toggle button's UI delegate to the default UI for
343 * the current look and feel.
344 */
345 public void updateUI()
346 {
347 setUI((ButtonUI)UIManager.getUI(this));
348 }
349
350 }