01 /*
02 * Copyright 1996-1998 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.beans;
27
28 /**
29 * Under some circumstances a bean may be run on servers where a GUI
30 * is not available. This interface can be used to query a bean to
31 * determine whether it absolutely needs a gui, and to advise the
32 * bean whether a GUI is available.
33 * <p>
34 * This interface is for expert developers, and is not needed
35 * for normal simple beans. To avoid confusing end-users we
36 * avoid using getXXX setXXX design patterns for these methods.
37 */
38
39 public interface Visibility {
40
41 /**
42 * Determines whether this bean needs a GUI.
43 *
44 * @return True if the bean absolutely needs a GUI available in
45 * order to get its work done.
46 */
47 boolean needsGui();
48
49 /**
50 * This method instructs the bean that it should not use the Gui.
51 */
52 void dontUseGui();
53
54 /**
55 * This method instructs the bean that it is OK to use the Gui.
56 */
57 void okToUseGui();
58
59 /**
60 * Determines whether this bean is avoiding using a GUI.
61 *
62 * @return true if the bean is currently avoiding use of the Gui.
63 * e.g. due to a call on dontUseGui().
64 */
65 boolean avoidingGui();
66
67 }
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