1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.collections.iterators;
18
19 import org.apache.commons.collections.MapIterator;
20 import org.apache.commons.collections.Unmodifiable;
21
22 /**
23 * Decorates a map iterator such that it cannot be modified.
24 * <p>
25 * Attempts to modify it will result in an UnsupportedOperationException.
26 *
27 * @since 3.0
28 * @version $Id: UnmodifiableMapIterator.java 1429905 2013-01-07 17:15:14Z ggregory $
29 */
30 public final class UnmodifiableMapIterator<K, V> implements MapIterator<K, V>, Unmodifiable {
31
32 /** The iterator being decorated */
33 private final MapIterator<K, V> iterator;
34
35 //-----------------------------------------------------------------------
36 /**
37 * Decorates the specified iterator such that it cannot be modified.
38 *
39 * @param <K> the key type
40 * @param <V> the value type
41 * @param iterator the iterator to decorate
42 * @return a new unmodifiable map iterator
43 * @throws IllegalArgumentException if the iterator is null
44 */
45 public static <K, V> MapIterator<K, V> unmodifiableMapIterator(final MapIterator<K, V> iterator) {
46 if (iterator == null) {
47 throw new IllegalArgumentException("MapIterator must not be null");
48 }
49 if (iterator instanceof Unmodifiable) {
50 return iterator;
51 }
52 return new UnmodifiableMapIterator<K, V>(iterator);
53 }
54
55 //-----------------------------------------------------------------------
56 /**
57 * Constructor.
58 *
59 * @param iterator the iterator to decorate
60 */
61 private UnmodifiableMapIterator(final MapIterator<K, V> iterator) {
62 super();
63 this.iterator = iterator;
64 }
65
66 //-----------------------------------------------------------------------
67 public boolean hasNext() {
68 return iterator.hasNext();
69 }
70
71 public K next() {
72 return iterator.next();
73 }
74
75 public K getKey() {
76 return iterator.getKey();
77 }
78
79 public V getValue() {
80 return iterator.getValue();
81 }
82
83 public V setValue(final V value) {
84 throw new UnsupportedOperationException("setValue() is not supported");
85 }
86
87 public void remove() {
88 throw new UnsupportedOperationException("remove() is not supported");
89 }
90
91 }