1 /*
2 * Copyright (c) 2000, 2014, 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 package javax.swing;
26
27 import java.awt.FocusTraversalPolicy;
28 import java.awt.Component;
29 import java.awt.Container;
30 import java.awt.Window;
31 import java.util.HashMap;
32 import java.util.HashSet;
33 import java.io.*;
34
35
36 /**
37 * A FocusTraversalPolicy which provides support for legacy applications which
38 * handle focus traversal via JComponent.setNextFocusableComponent or by
39 * installing a custom DefaultFocusManager. If a specific traversal has not
40 * been hard coded, then that traversal is provided either by the custom
41 * DefaultFocusManager, or by a wrapped FocusTraversalPolicy instance.
42 *
43 * @author David Mendenhall
44 */
45 @SuppressWarnings("serial") // JDK-implementation class
46 final class LegacyGlueFocusTraversalPolicy extends FocusTraversalPolicy
47 implements Serializable
48 {
49 private transient FocusTraversalPolicy delegatePolicy;
50 private transient DefaultFocusManager delegateManager;
51
52 private HashMap<Component, Component> forwardMap = new HashMap<Component, Component>(),
53 backwardMap = new HashMap<Component, Component>();
54
55 LegacyGlueFocusTraversalPolicy(FocusTraversalPolicy delegatePolicy) {
56 this.delegatePolicy = delegatePolicy;
57 }
58 LegacyGlueFocusTraversalPolicy(DefaultFocusManager delegateManager) {
59 this.delegateManager = delegateManager;
60 }
61
62 void setNextFocusableComponent(Component left, Component right) {
63 forwardMap.put(left, right);
64 backwardMap.put(right, left);
65 }
66 void unsetNextFocusableComponent(Component left, Component right) {
67 forwardMap.remove(left);
68 backwardMap.remove(right);
69 }
70
71 public Component getComponentAfter(Container focusCycleRoot,
72 Component aComponent) {
73 Component hardCoded = aComponent, prevHardCoded;
74 HashSet<Component> sanity = new HashSet<Component>();
75
76 do {
77 prevHardCoded = hardCoded;
78 hardCoded = forwardMap.get(hardCoded);
79 if (hardCoded == null) {
80 if (delegatePolicy != null &&
81 prevHardCoded.isFocusCycleRoot(focusCycleRoot)) {
82 return delegatePolicy.getComponentAfter(focusCycleRoot,
83 prevHardCoded);
84 } else if (delegateManager != null) {
85 return delegateManager.
86 getComponentAfter(focusCycleRoot, aComponent);
87 } else {
88 return null;
89 }
90 }
91 if (sanity.contains(hardCoded)) {
92 // cycle detected; bail
93 return null;
94 }
95 sanity.add(hardCoded);
96 } while (!accept(hardCoded));
97
98 return hardCoded;
99 }
100 public Component getComponentBefore(Container focusCycleRoot,
101 Component aComponent) {
102 Component hardCoded = aComponent, prevHardCoded;
103 HashSet<Component> sanity = new HashSet<Component>();
104
105 do {
106 prevHardCoded = hardCoded;
107 hardCoded = backwardMap.get(hardCoded);
108 if (hardCoded == null) {
109 if (delegatePolicy != null &&
110 prevHardCoded.isFocusCycleRoot(focusCycleRoot)) {
111 return delegatePolicy.getComponentBefore(focusCycleRoot,
112 prevHardCoded);
113 } else if (delegateManager != null) {
114 return delegateManager.
115 getComponentBefore(focusCycleRoot, aComponent);
116 } else {
117 return null;
118 }
119 }
120 if (sanity.contains(hardCoded)) {
121 // cycle detected; bail
122 return null;
123 }
124 sanity.add(hardCoded);
125 } while (!accept(hardCoded));
126
127 return hardCoded;
128 }
129 public Component getFirstComponent(Container focusCycleRoot) {
130 if (delegatePolicy != null) {
131 return delegatePolicy.getFirstComponent(focusCycleRoot);
132 } else if (delegateManager != null) {
133 return delegateManager.getFirstComponent(focusCycleRoot);
134 } else {
135 return null;
136 }
137 }
138 public Component getLastComponent(Container focusCycleRoot) {
139 if (delegatePolicy != null) {
140 return delegatePolicy.getLastComponent(focusCycleRoot);
141 } else if (delegateManager != null) {
142 return delegateManager.getLastComponent(focusCycleRoot);
143 } else {
144 return null;
145 }
146 }
147 public Component getDefaultComponent(Container focusCycleRoot) {
148 if (delegatePolicy != null) {
149 return delegatePolicy.getDefaultComponent(focusCycleRoot);
150 } else {
151 return getFirstComponent(focusCycleRoot);
152 }
153 }
154 private boolean accept(Component aComponent) {
155 if (!(aComponent.isVisible() && aComponent.isDisplayable() &&
156 aComponent.isFocusable() && aComponent.isEnabled())) {
157 return false;
158 }
159
160 // Verify that the Component is recursively enabled. Disabling a
161 // heavyweight Container disables its children, whereas disabling
162 // a lightweight Container does not.
163 if (!(aComponent instanceof Window)) {
164 for (Container enableTest = aComponent.getParent();
165 enableTest != null;
166 enableTest = enableTest.getParent())
167 {
168 if (!(enableTest.isEnabled() || enableTest.isLightweight())) {
169 return false;
170 }
171 if (enableTest instanceof Window) {
172 break;
173 }
174 }
175 }
176
177 return true;
178 }
179 private void writeObject(ObjectOutputStream out) throws IOException {
180 out.defaultWriteObject();
181
182 if (delegatePolicy instanceof Serializable) {
183 out.writeObject(delegatePolicy);
184 } else {
185 out.writeObject(null);
186 }
187
188 if (delegateManager instanceof Serializable) {
189 out.writeObject(delegateManager);
190 } else {
191 out.writeObject(null);
192 }
193 }
194 private void readObject(ObjectInputStream in)
195 throws IOException, ClassNotFoundException
196 {
197 in.defaultReadObject();
198 delegatePolicy = (FocusTraversalPolicy)in.readObject();
199 delegateManager = (DefaultFocusManager)in.readObject();
200 }
201 }