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.ResettableIterator;
21
22 /**
23 * Provides an implementation of an empty map iterator.
24 *
25 * @since 3.1
26 * @version $Id: EmptyMapIterator.java 1369925 2012-08-06 19:11:31Z tn $
27 */
28 public class EmptyMapIterator<K, V> extends AbstractEmptyMapIterator<K, V> implements
29 MapIterator<K, V>, ResettableIterator<K> {
30
31 /**
32 * Singleton instance of the iterator.
33 * @since 3.1
34 */
35 public static final MapIterator<Object, Object> INSTANCE = new EmptyMapIterator<Object, Object>();
36
37 /**
38 * Get a typed instance of the iterator.
39 * @param <K> the key type
40 * @param <V> the value type
41 * @return {@link MapIterator}<K, V>
42 */
43 @SuppressWarnings("unchecked")
44 public static <K, V> MapIterator<K, V> emptyMapIterator() {
45 return (MapIterator<K, V>) INSTANCE;
46 }
47
48 /**
49 * Constructor.
50 */
51 protected EmptyMapIterator() {
52 super();
53 }
54
55 }