001 /* FocusTraversalPolicy.java --
002 Copyright (C) 2002 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
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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
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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
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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 java.awt;
040
041 /**
042 * @since 1.4
043 */
044 public abstract class FocusTraversalPolicy
045 {
046 /**
047 * Creates a <code>FocusTraversalPolicy</code> object.
048 */
049 public FocusTraversalPolicy()
050 {
051 // Do nothing in here.
052 }
053
054 /**
055 * Returns the Component that should receive the focus after a Component.
056 *
057 * @exception IllegalArgumentException If root or current is null,
058 * or if root is not a focus cycle root of current.
059 */
060 public abstract Component getComponentAfter(Container root,
061 Component current);
062
063 /**
064 * Returns the Component that should receive the focus before a Component.
065 *
066 * @exception IllegalArgumentException If root or current is null,
067 * or if root is not a focus cycle root of current.
068 */
069 public abstract Component getComponentBefore(Container root,
070 Component current);
071
072 /**
073 * Returns the first Component in the traversal cycle.
074 *
075 * @exception IllegalArgumentException If root is null.
076 */
077 public abstract Component getFirstComponent(Container root);
078
079 /**
080 * Returns the last Component in the traversal cycle.
081 *
082 * @exception IllegalArgumentException If root is null.
083 */
084 public abstract Component getLastComponent(Container root);
085
086 /**
087 * Returns the default Component to focus.
088 *
089 * @exception IllegalArgumentException If root is null.
090 */
091 public abstract Component getDefaultComponent(Container root);
092
093 /**
094 * Returns the Component that should receive the focus when a Window is made
095 * visible for the first time.
096 *
097 * @exception IllegalArgumentException If window is null.
098 */
099 public Component getInitialComponent(Window window)
100 {
101 return getDefaultComponent(window);
102 }
103 } // class FocusTraversalPolicy