1 /* CompatibilityFocusTraversalPolicy.java -- Provides compatibility to old
2 focus API
3 Copyright (C) 2006 Free Software Foundation, Inc.
4
5 This file is part of GNU Classpath.
6
7 GNU Classpath is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
10 any later version.
11
12 GNU Classpath is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GNU Classpath; see the file COPYING. If not, write to the
19 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 02110-1301 USA.
21
22 Linking this library statically or dynamically with other modules is
23 making a combined work based on this library. Thus, the terms and
24 conditions of the GNU General Public License cover the whole
25 combination.
26
27 As a special exception, the copyright holders of this library give you
28 permission to link this library with independent modules to produce an
29 executable, regardless of the license terms of these independent
30 modules, and to copy and distribute the resulting executable under
31 terms of your choice, provided that you also meet, for each linked
32 independent module, the terms and conditions of the license of that
33 module. An independent module is a module which is not derived from
34 or based on this library. If you modify this library, you may extend
35 this exception to your version of the library, but you are not
36 obligated to do so. If you do not wish to do so, delete this
37 exception statement from your version. */
38
39
40 package javax.swing;
41
42 import java.awt.Component;
43 import java.awt.Container;
44 import java.awt.FocusTraversalPolicy;
45 import java.util.HashMap;
46
47 /**
48 * Provides compatibility to the older focus API in
49 * {@link JComponent#setNextFocusableComponent(Component)}.
50 *
51 * @author Roman Kennke (kennke@aicas.com)
52 */
53 class CompatibilityFocusTraversalPolicy
54 extends FocusTraversalPolicy
55 {
56
57 /**
58 * The focus traversal policy that has been installed on the focus cycle
59 * root before, and to which we fall back.
60 */
61 private FocusTraversalPolicy fallback;
62
63 /**
64 * Maps components to their next focused components.
65 */
66 private HashMap forward;
67
68 /**
69 * Maps components to their previous focused components.
70 */
71 private HashMap backward;
72
73 /**
74 * Creates a new CompatibilityFocusTraversalPolicy with the specified
75 * policy as fallback.
76 *
77 * @param p the fallback policy
78 */
79 CompatibilityFocusTraversalPolicy(FocusTraversalPolicy p)
80 {
81 fallback = p;
82 forward = new HashMap();
83 backward = new HashMap();
84 }
85
86 public Component getComponentAfter(Container root, Component current)
87 {
88 Component next = (Component) forward.get(current);
89 if (next == null && fallback != null)
90 next = fallback.getComponentAfter(root, current);
91 return next;
92 }
93
94 public Component getComponentBefore(Container root, Component current)
95 {
96 Component previous = (Component) backward.get(current);
97 if (previous == null && fallback != null)
98 previous = fallback.getComponentAfter(root, current);
99 return previous;
100 }
101
102 public Component getFirstComponent(Container root)
103 {
104 Component first = null;
105 if (fallback != null)
106 first = fallback.getFirstComponent(root);
107 return first;
108 }
109
110 public Component getLastComponent(Container root)
111 {
112 Component last = null;
113 if (fallback != null)
114 last = fallback.getLastComponent(root);
115 return last;
116 }
117
118 public Component getDefaultComponent(Container root)
119 {
120 Component def = null;
121 if (fallback != null)
122 def = fallback.getDefaultComponent(root);
123 return def;
124 }
125
126 /**
127 * Sets a next focused component for a specified component. This is called
128 * by {@link JComponent#setNextFocusableComponent(Component)}.
129 *
130 * @param current the current component
131 * @param next the next focused component
132 */
133 void setNextFocusableComponent(Component current, Component next)
134 {
135 forward.put(current, next);
136 backward.put(next, current);
137 }
138
139 /**
140 * Sets a next focused component for a specified component. This is called
141 * by {@link JComponent#setNextFocusableComponent(Component)}.
142 *
143 * @param current the current component
144 * @param next the next focused component
145 */
146 void addNextFocusableComponent(Component current, Component next)
147 {
148 forward.put(current, next);
149 backward.put(next, current);
150 }
151
152 /**
153 * Removes a focused component mapping. This is called
154 * by {@link JComponent#setNextFocusableComponent(Component)}.
155 *
156 * @param current the current component
157 * @param next the next focused component
158 */
159 void removeNextFocusableComponent(Component current, Component next)
160 {
161 forward.remove(current);
162 backward.remove(next);
163 }
164 }
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