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 *      https://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 */
017
018package org.apache.commons.collections4;
019
020/**
021 * Defines an iterator that operates over an ordered {@code Map}.
022 * <p>
023 * This iterator allows both forward and reverse iteration through the map.
024 * </p>
025 *
026 * @param <K> The type of the keys in the map
027 * @param <V> The type of the values in the map
028 * @since 3.0
029 */
030public interface OrderedMapIterator<K, V> extends MapIterator<K, V>, OrderedIterator<K> {
031
032    /**
033     * Checks to see if there is a previous entry that can be iterated to.
034     *
035     * @return {@code true} if the iterator has a previous element.
036     */
037    @Override
038    boolean hasPrevious();
039
040    /**
041     * Gets the previous <em>key</em> from the {@code Map}.
042     *
043     * @return The previous key in the iteration.
044     * @throws java.util.NoSuchElementException if the iteration is finished.
045     */
046    @Override
047    K previous();
048}