javax.faces.TypedCollections Maven / Gradle / Ivy
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package javax.faces;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;
class TypedCollections {
/**
* Dynamically check that the members of the collection are all
* instances of the given type (or null).
*/
private static boolean checkCollectionMembers(Collection c, Class type) {
for (Object element : c) {
if (element != null && !type.isInstance(element)) {
return false;
}
}
return true;
}
/**
* Dynamically check that the members of the collection are all
* instances of the given type (or null), and that the collection
* itself is of the given collection type.
*
* @param
* the collection's element type
* @param c
* the collection to cast
* @param type
* the class of the collection's element type.
* @return the dynamically-type checked collection.
* @throws java.lang.ClassCastException
*/
@SuppressWarnings("unchecked")
static > TypedC dynamicallyCastCollection(Collection c,
Class type,
Class collectionType) {
if (c == null)
return null;
if (!collectionType.isInstance(c))
throw new ClassCastException(c.getClass().getName());
assert checkCollectionMembers(c, type) :
"The collection contains members with a type other than " + type.getName();
return collectionType.cast(c);
}
/**
* Dynamically check that the members of the list are all instances of
* the given type (or null).
*
* @param
* the list's element type
* @param list
* the list to cast
* @param type
* the class of the list's element type.
* @return the dynamically-type checked list.
* @throws java.lang.ClassCastException
*/
@SuppressWarnings("unchecked")
static List dynamicallyCastList(List list, Class type) {
return dynamicallyCastCollection(list, type, List.class);
}
/**
* Dynamically check that the members of the set are all instances of
* the given type (or null).
*
* @param
* the set's element type
* @param set
* the set to cast
* @param type
* the class of the set's element type.
* @return the dynamically-type checked set.
* @throws java.lang.ClassCastException
*/
@SuppressWarnings("unchecked")
static Set dynamicallyCastSet(Set set,
Class type) {
return dynamicallyCastCollection(set, type, Set.class);
}
/**
* Dynamically check that the keys and values in the map are all
* instances of the correct types (or null).
*
* @param
* the map's key type
* @param
* the map's value type
* @param map
* the map to cast
* @param keyType
* the class of the map's key type.
* @param valueType
* the class of the map's value type.
* @return the dynamically-type checked map.
* @throws java.lang.ClassCastException
*/
@SuppressWarnings("unchecked")
static Map dynamicallyCastMap(Map map,
Class keyType,
Class valueType) {
if (map == null) {
return null;
}
assert checkCollectionMembers(map.keySet(), keyType) :
"The map contains keys with a type other than " + keyType.getName();
assert checkCollectionMembers(map.values(), valueType) :
"The map contains values with a type other than " + valueType.getName();
return (Map) map;
}
}