001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.collections.list;
018
019 import java.util.Collection;
020 import java.util.Iterator;
021 import java.util.List;
022 import java.util.ListIterator;
023
024 import org.apache.commons.collections.Unmodifiable;
025 import org.apache.commons.collections.iterators.UnmodifiableIterator;
026 import org.apache.commons.collections.iterators.UnmodifiableListIterator;
027
028 /**
029 * Decorates another <code>List</code> to ensure it can't be altered.
030 * <p>
031 * This class is Serializable from Commons Collections 3.1.
032 *
033 * @since Commons Collections 3.0
034 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
035 *
036 * @author Stephen Colebourne
037 */
038 public final class UnmodifiableList
039 extends AbstractSerializableListDecorator
040 implements Unmodifiable {
041
042 /** Serialization version */
043 private static final long serialVersionUID = 6595182819922443652L;
044
045 /**
046 * Factory method to create an unmodifiable list.
047 *
048 * @param list the list to decorate, must not be null
049 * @throws IllegalArgumentException if list is null
050 */
051 public static List decorate(List list) {
052 if (list instanceof Unmodifiable) {
053 return list;
054 }
055 return new UnmodifiableList(list);
056 }
057
058 //-----------------------------------------------------------------------
059 /**
060 * Constructor that wraps (not copies).
061 *
062 * @param list the list to decorate, must not be null
063 * @throws IllegalArgumentException if list is null
064 */
065 private UnmodifiableList(List list) {
066 super(list);
067 }
068
069 //-----------------------------------------------------------------------
070 public Iterator iterator() {
071 return UnmodifiableIterator.decorate(getCollection().iterator());
072 }
073
074 public boolean add(Object object) {
075 throw new UnsupportedOperationException();
076 }
077
078 public boolean addAll(Collection coll) {
079 throw new UnsupportedOperationException();
080 }
081
082 public void clear() {
083 throw new UnsupportedOperationException();
084 }
085
086 public boolean remove(Object object) {
087 throw new UnsupportedOperationException();
088 }
089
090 public boolean removeAll(Collection coll) {
091 throw new UnsupportedOperationException();
092 }
093
094 public boolean retainAll(Collection coll) {
095 throw new UnsupportedOperationException();
096 }
097
098 //-----------------------------------------------------------------------
099 public ListIterator listIterator() {
100 return UnmodifiableListIterator.decorate(getList().listIterator());
101 }
102
103 public ListIterator listIterator(int index) {
104 return UnmodifiableListIterator.decorate(getList().listIterator(index));
105 }
106
107 public void add(int index, Object object) {
108 throw new UnsupportedOperationException();
109 }
110
111 public boolean addAll(int index, Collection coll) {
112 throw new UnsupportedOperationException();
113 }
114
115 public Object remove(int index) {
116 throw new UnsupportedOperationException();
117 }
118
119 public Object set(int index, Object object) {
120 throw new UnsupportedOperationException();
121 }
122
123 public List subList(int fromIndex, int toIndex) {
124 List sub = getList().subList(fromIndex, toIndex);
125 return new UnmodifiableList(sub);
126 }
127
128 }