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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.collections4.iterators;
18  
19  import org.apache.commons.collections4.MapIterator;
20  import org.apache.commons.collections4.ResettableIterator;
21  
22  /**
23   * Provides an implementation of an empty map iterator.
24   *
25   * @param <K> the type of keys
26   * @param <V> the type of mapped values
27   * @since 3.1
28   */
29  public class EmptyMapIterator<K, V> extends AbstractEmptyMapIterator<K, V> implements
30          MapIterator<K, V>, ResettableIterator<K> {
31  
32      /**
33       * Singleton instance of the iterator.
34       * @since 3.1
35       */
36      @SuppressWarnings("rawtypes")
37      public static final MapIterator INSTANCE = new EmptyMapIterator<>();
38  
39      /**
40       * Get a typed instance of the iterator.
41       * @param <K> the key type
42       * @param <V> the value type
43       * @return {@link MapIterator}&lt;K, V&gt;
44       */
45      public static <K, V> MapIterator<K, V> emptyMapIterator() {
46          return INSTANCE;
47      }
48  
49      /**
50       * Constructor.
51       */
52      protected EmptyMapIterator() {
53          super();
54      }
55  
56  }