1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
5 *
6 * The contents of this file are subject to the terms of either the GNU
7 * General Public License Version 2 only ("GPL") or the Common Development
8 * and Distribution License("CDDL") (collectively, the "License"). You
9 * may not use this file except in compliance with the License. You can obtain
10 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
11 * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
12 * language governing permissions and limitations under the License.
13 *
14 * When distributing the software, include this License Header Notice in each
15 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
16 * Sun designates this particular file as subject to the "Classpath" exception
17 * as provided by Sun in the GPL Version 2 section of the License file that
18 * accompanied this code. If applicable, add the following below the License
19 * Header, with the fields enclosed by brackets [] replaced by your own
20 * identifying information: "Portions Copyrighted [year]
21 * [name of copyright owner]"
22 *
23 * Contributor(s):
24 *
25 * If you wish your version of this file to be governed by only the CDDL or
26 * only the GPL Version 2, indicate your decision by adding "[Contributor]
27 * elects to include this software in this distribution under the [CDDL or GPL
28 * Version 2] license." If you don't indicate a single choice of license, a
29 * recipient has the option to distribute your version of this file under
30 * either the CDDL, the GPL Version 2 or to extend the choice of license to
31 * its licensees as provided above. However, if you add GPL Version 2 code
32 * and therefore, elected the GPL Version 2 license, then the option applies
33 * only if the new code is made subject to such option by the copyright
34 * holder.
35 */
36
37 package javax.faces.component;
38
39 import java.util.Collection;
40 import java.util.List;
41 import java.util.Map;
42 import java.util.Set;
43
44 class TypedCollections {
45
46 /**
47 * Dynamically check that the members of the collection are all
48 * instances of the given type (or null).
49 */
50 private static boolean checkCollectionMembers(Collection<?> c, Class<?> type) {
51 for (Object element : c) {
52 if (element != null && !type.isInstance(element)) {
53 return false;
54 }
55 }
56 return true;
57 }
58
59 /**
60 * Dynamically check that the members of the collection are all
61 * instances of the given type (or null), and that the collection
62 * itself is of the given collection type.
63 *
64 * @param <E>
65 * the collection's element type
66 * @param c
67 * the collection to cast
68 * @param type
69 * the class of the collection's element type.
70 * @return the dynamically-type checked collection.
71 * @throws java.lang.ClassCastException
72 */
73 @SuppressWarnings("unchecked")
74 static <E,TypedC extends Collection<E>> TypedC dynamicallyCastCollection(Collection<?> c,
75 Class<E> type,
76 Class<TypedC> collectionType) {
77 if (c == null)
78 return null;
79 if (!collectionType.isInstance(c))
80 throw new ClassCastException(c.getClass().getName());
81 assert checkCollectionMembers(c, type) :
82 "The collection contains members with a type other than " + type.getName();
83
84 return collectionType.cast(c);
85 }
86
87 /**
88 * Dynamically check that the members of the list are all instances of
89 * the given type (or null).
90 *
91 * @param <E>
92 * the list's element type
93 * @param list
94 * the list to cast
95 * @param type
96 * the class of the list's element type.
97 * @return the dynamically-type checked list.
98 * @throws java.lang.ClassCastException
99 */
100 @SuppressWarnings("unchecked")
101 static <E> List<E> dynamicallyCastList(List<?> list, Class<E> type) {
102 return dynamicallyCastCollection(list, type, List.class);
103 }
104
105 /**
106 * Dynamically check that the members of the set are all instances of
107 * the given type (or null).
108 *
109 * @param <E>
110 * the set's element type
111 * @param set
112 * the set to cast
113 * @param type
114 * the class of the set's element type.
115 * @return the dynamically-type checked set.
116 * @throws java.lang.ClassCastException
117 */
118 @SuppressWarnings("unchecked")
119 static <E> Set<E> dynamicallyCastSet(Set<?> set,
120 Class<E> type) {
121 return dynamicallyCastCollection(set, type, Set.class);
122 }
123
124 /**
125 * Dynamically check that the keys and values in the map are all
126 * instances of the correct types (or null).
127 *
128 * @param <K>
129 * the map's key type
130 * @param <V>
131 * the map's value type
132 * @param map
133 * the map to cast
134 * @param keyType
135 * the class of the map's key type.
136 * @param keyType
137 * the class of the map's key type.
138 * @return the dynamically-type checked map.
139 * @throws java.lang.ClassCastException
140 */
141 @SuppressWarnings("unchecked")
142 static <K, V> Map<K, V> dynamicallyCastMap(Map<?, ?> map,
143 Class<K> keyType,
144 Class<V> valueType) {
145 if (map == null) {
146 return null;
147 }
148 assert checkCollectionMembers(map.keySet(), keyType) :
149 "The map contains keys with a type other than " + keyType.getName();
150 assert checkCollectionMembers(map.values(), valueType) :
151 "The map contains values with a type other than " + valueType.getName();
152
153 return (Map<K, V>) map;
154 }
155 }