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; 018 019import java.util.Iterator; 020 021/** 022 * Defines an iterator that operates over an ordered container. Subset of {@link java.util.ListIterator}. 023 * <p> 024 * This iterator allows both forward and reverse iteration through the container. 025 * </p> 026 * 027 * @param <E> the type of elements returned by this iterator 028 * @since 3.0 029 */ 030public interface OrderedIterator<E> extends Iterator<E> { 031 032 /** 033 * Checks to see if there is a previous element that can be iterated to. 034 * 035 * @return <code>true</code> if the iterator has a previous element 036 */ 037 boolean hasPrevious(); 038 039 /** 040 * Gets the previous element from the container. 041 * 042 * @return the previous element in the iteration 043 * @throws java.util.NoSuchElementException if the iteration is finished 044 */ 045 E previous(); 046 047}