1 /*
2 * Copyright 1996-2008 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.awt.event;
27
28 import java.awt.AWTEvent;
29 import java.awt.Event;
30
31 /**
32 * A semantic event which indicates that a component-defined action occurred.
33 * This high-level event is generated by a component (such as a
34 * <code>Button</code>) when
35 * the component-specific action occurs (such as being pressed).
36 * The event is passed to every <code>ActionListener</code> object
37 * that registered to receive such events using the component's
38 * <code>addActionListener</code> method.
39 * <p>
40 * <b>Note:</b> To invoke an <code>ActionEvent</code> on a
41 * <code>Button</code> using the keyboard, use the Space bar.
42 * <P>
43 * The object that implements the <code>ActionListener</code> interface
44 * gets this <code>ActionEvent</code> when the event occurs. The listener
45 * is therefore spared the details of processing individual mouse movements
46 * and mouse clicks, and can instead process a "meaningful" (semantic)
47 * event like "button pressed".
48 * <p>
49 * An unspecified behavior will be caused if the {@code id} parameter
50 * of any particular {@code ActionEvent} instance is not
51 * in the range from {@code ACTION_FIRST} to {@code ACTION_LAST}.
52 *
53 * @see ActionListener
54 * @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/eventmodel.html">Tutorial: Java 1.1 Event Model</a>
55 *
56 * @author Carl Quinn
57 * @since 1.1
58 */
59 public class ActionEvent extends AWTEvent {
60
61 /**
62 * The shift modifier. An indicator that the shift key was held
63 * down during the event.
64 */
65 public static final int SHIFT_MASK = Event.SHIFT_MASK;
66
67 /**
68 * The control modifier. An indicator that the control key was held
69 * down during the event.
70 */
71 public static final int CTRL_MASK = Event.CTRL_MASK;
72
73 /**
74 * The meta modifier. An indicator that the meta key was held
75 * down during the event.
76 */
77 public static final int META_MASK = Event.META_MASK;
78
79 /**
80 * The alt modifier. An indicator that the alt key was held
81 * down during the event.
82 */
83 public static final int ALT_MASK = Event.ALT_MASK;
84
85
86 /**
87 * The first number in the range of ids used for action events.
88 */
89 public static final int ACTION_FIRST = 1001;
90
91 /**
92 * The last number in the range of ids used for action events.
93 */
94 public static final int ACTION_LAST = 1001;
95
96 /**
97 * This event id indicates that a meaningful action occured.
98 */
99 public static final int ACTION_PERFORMED = ACTION_FIRST; //Event.ACTION_EVENT
100
101 /**
102 * The nonlocalized string that gives more details
103 * of what actually caused the event.
104 * This information is very specific to the component
105 * that fired it.
106
107 * @serial
108 * @see #getActionCommand
109 */
110 String actionCommand;
111
112 /**
113 * Timestamp of when this event occurred. Because an ActionEvent is a high-
114 * level, semantic event, the timestamp is typically the same as an
115 * underlying InputEvent.
116 *
117 * @serial
118 * @see #getWhen
119 */
120 long when;
121
122 /**
123 * This represents the key modifier that was selected,
124 * and is used to determine the state of the selected key.
125 * If no modifier has been selected it will default to
126 * zero.
127 *
128 * @serial
129 * @see #getModifiers
130 */
131 int modifiers;
132
133 /*
134 * JDK 1.1 serialVersionUID
135 */
136 private static final long serialVersionUID = -7671078796273832149L;
137
138 /**
139 * Constructs an <code>ActionEvent</code> object.
140 * <p>
141 * This method throws an
142 * <code>IllegalArgumentException</code> if <code>source</code>
143 * is <code>null</code>.
144 * A <code>null</code> <code>command</code> string is legal,
145 * but not recommended.
146 *
147 * @param source The object that originated the event
148 * @param id An integer that identifies the event.
149 * For information on allowable values, see
150 * the class description for {@link ActionEvent}
151 * @param command A string that may specify a command (possibly one
152 * of several) associated with the event
153 * @throws IllegalArgumentException if <code>source</code> is null
154 * @see #getSource()
155 * @see #getID()
156 * @see #getActionCommand()
157 */
158 public ActionEvent(Object source, int id, String command) {
159 this(source, id, command, 0);
160 }
161
162 /**
163 * Constructs an <code>ActionEvent</code> object with modifier keys.
164 * <p>
165 * This method throws an
166 * <code>IllegalArgumentException</code> if <code>source</code>
167 * is <code>null</code>.
168 * A <code>null</code> <code>command</code> string is legal,
169 * but not recommended.
170 *
171 * @param source The object that originated the event
172 * @param id An integer that identifies the event.
173 * For information on allowable values, see
174 * the class description for {@link ActionEvent}
175 * @param command A string that may specify a command (possibly one
176 * of several) associated with the event
177 * @param modifiers The modifier keys down during event
178 * (shift, ctrl, alt, meta).
179 * Passing negative parameter is not recommended.
180 * Zero value means that no modifiers were passed
181 * @throws IllegalArgumentException if <code>source</code> is null
182 * @see #getSource()
183 * @see #getID()
184 * @see #getActionCommand()
185 * @see #getModifiers()
186 */
187 public ActionEvent(Object source, int id, String command, int modifiers) {
188 this(source, id, command, 0, modifiers);
189 }
190
191 /**
192 * Constructs an <code>ActionEvent</code> object with the specified
193 * modifier keys and timestamp.
194 * <p>
195 * This method throws an
196 * <code>IllegalArgumentException</code> if <code>source</code>
197 * is <code>null</code>.
198 * A <code>null</code> <code>command</code> string is legal,
199 * but not recommended.
200 *
201 * @param source The object that originated the event
202 * @param id An integer that identifies the event.
203 * For information on allowable values, see
204 * the class description for {@link ActionEvent}
205 * @param command A string that may specify a command (possibly one
206 * of several) associated with the event
207 * @param modifiers The modifier keys down during event
208 * (shift, ctrl, alt, meta).
209 * Passing negative parameter is not recommended.
210 * Zero value means that no modifiers were passed
211 * @param when A long that gives the time the event occurred.
212 * Passing negative or zero value
213 * is not recommended
214 * @throws IllegalArgumentException if <code>source</code> is null
215 * @see #getSource()
216 * @see #getID()
217 * @see #getActionCommand()
218 * @see #getModifiers()
219 * @see #getWhen()
220 *
221 * @since 1.4
222 */
223 public ActionEvent(Object source, int id, String command, long when,
224 int modifiers) {
225 super(source, id);
226 this.actionCommand = command;
227 this.when = when;
228 this.modifiers = modifiers;
229 }
230
231 /**
232 * Returns the command string associated with this action.
233 * This string allows a "modal" component to specify one of several
234 * commands, depending on its state. For example, a single button might
235 * toggle between "show details" and "hide details". The source object
236 * and the event would be the same in each case, but the command string
237 * would identify the intended action.
238 * <p>
239 * Note that if a <code>null</code> command string was passed
240 * to the constructor for this <code>ActionEvent</code>, this
241 * this method returns <code>null</code>.
242 *
243 * @return the string identifying the command for this event
244 */
245 public String getActionCommand() {
246 return actionCommand;
247 }
248
249 /**
250 * Returns the timestamp of when this event occurred. Because an
251 * ActionEvent is a high-level, semantic event, the timestamp is typically
252 * the same as an underlying InputEvent.
253 *
254 * @return this event's timestamp
255 * @since 1.4
256 */
257 public long getWhen() {
258 return when;
259 }
260
261 /**
262 * Returns the modifier keys held down during this action event.
263 *
264 * @return the bitwise-or of the modifier constants
265 */
266 public int getModifiers() {
267 return modifiers;
268 }
269
270 /**
271 * Returns a parameter string identifying this action event.
272 * This method is useful for event-logging and for debugging.
273 *
274 * @return a string identifying the event and its associated command
275 */
276 public String paramString() {
277 String typeStr;
278 switch(id) {
279 case ACTION_PERFORMED:
280 typeStr = "ACTION_PERFORMED";
281 break;
282 default:
283 typeStr = "unknown type";
284 }
285 return typeStr + ",cmd="+actionCommand+",when="+when+",modifiers="+
286 KeyEvent.getKeyModifiersText(modifiers);
287 }
288 }
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