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 * @param <K> the type of keys
026 * @param <V> the type of mapped values
027 * @since 3.1
028 */
029public class EmptyMapIterator<K, V> extends AbstractEmptyMapIterator<K, V> implements
030        MapIterator<K, V>, ResettableIterator<K> {
031
032    /**
033     * Singleton instance of the iterator.
034     * @since 3.1
035     */
036    @SuppressWarnings("rawtypes")
037    public static final MapIterator INSTANCE = new EmptyMapIterator<>();
038
039    /**
040     * Gets a typed instance of the iterator.
041     * @param <K> the key type
042     * @param <V> the value type
043     * @return {@link MapIterator}&lt;K, V&gt;
044     */
045    public static <K, V> MapIterator<K, V> emptyMapIterator() {
046        return INSTANCE;
047    }
048
049    /**
050     * Constructs a new instance.
051     */
052    protected EmptyMapIterator() {
053    }
054
055}