1 /*
   2  * Copyright (c) 1996, 1998, Oracle and/or its affiliates. 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * 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 }