01 /*
02 * Copyright 1996-2006 Sun Microsystems, Inc. All Rights Reserved.
03 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04 *
05 * This code is free software; you can redistribute it and/or modify it
06 * under the terms of the GNU General Public License version 2 only, as
07 * published by the Free Software Foundation. Sun designates this
08 * particular file as subject to the "Classpath" exception as provided
09 * 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 /**
29 * An abstract adapter class for receiving keyboard focus events.
30 * The methods in this class are empty. This class exists as
31 * convenience for creating listener objects.
32 * <P>
33 * Extend this class to create a <code>FocusEvent</code> listener
34 * and override the methods for the events of interest. (If you implement the
35 * <code>FocusListener</code> interface, you have to define all of
36 * the methods in it. This abstract class defines null methods for them
37 * all, so you can only have to define methods for events you care about.)
38 * <P>
39 * Create a listener object using the extended class and then register it with
40 * a component using the component's <code>addFocusListener</code>
41 * method. When the component gains or loses the keyboard focus,
42 * the relevant method in the listener object is invoked,
43 * and the <code>FocusEvent</code> is passed to it.
44 *
45 * @see FocusEvent
46 * @see FocusListener
47 * @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/focuslistener.html">Tutorial: Writing a Focus Listener</a>
48 *
49 * @author Carl Quinn
50 * @version 1.24 05/05/07
51 * @since 1.1
52 */
53 public abstract class FocusAdapter implements FocusListener {
54 /**
55 * Invoked when a component gains the keyboard focus.
56 */
57 public void focusGained(FocusEvent e) {
58 }
59
60 /**
61 * Invoked when a component loses the keyboard focus.
62 */
63 public void focusLost(FocusEvent e) {
64 }
65 }
|