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 */
017package org.apache.commons.collections4.iterators;
018
019import org.apache.commons.collections4.MapIterator;
020import org.apache.commons.collections4.ResettableIterator;
021
022/**
023 * Provides an implementation of an empty map iterator.
024 *
025 * @since 3.1
026 * @version $Id: EmptyMapIterator.html 972421 2015-11-14 20:00:04Z tn $
027 */
028public class EmptyMapIterator<K, V> extends AbstractEmptyMapIterator<K, V> implements
029        MapIterator<K, V>, ResettableIterator<K> {
030
031    /**
032     * Singleton instance of the iterator.
033     * @since 3.1
034     */
035    @SuppressWarnings("rawtypes")
036    public static final MapIterator INSTANCE = new EmptyMapIterator<Object, Object>();
037
038    /**
039     * Get a typed instance of the iterator.
040     * @param <K> the key type
041     * @param <V> the value type
042     * @return {@link MapIterator}<K, V>
043     */
044    @SuppressWarnings("unchecked")
045    public static <K, V> MapIterator<K, V> emptyMapIterator() {
046        return (MapIterator<K, V>) INSTANCE;
047    }
048
049    /**
050     * Constructor.
051     */
052    protected EmptyMapIterator() {
053        super();
054    }
055
056}