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.wicket.util.collections; 018 019import java.util.Iterator; 020import java.util.List; 021import java.util.ListIterator; 022 023/** 024 * An iterator over {@link List} which goes from the end to the start 025 * 026 * @param <E> 027 */ 028public class ReverseListIterator<E> implements Iterator<E>, Iterable<E> 029{ 030 private final ListIterator<E> delegateIterator; 031 032 /** 033 * Construct. 034 * 035 * @param list 036 * the list which will be iterated in reverse order 037 */ 038 public ReverseListIterator(final List<E> list) 039 { 040 int start = list.size(); 041 this.delegateIterator = list.listIterator(start); 042 } 043 044 @Override 045 public boolean hasNext() 046 { 047 return delegateIterator.hasPrevious(); 048 } 049 050 @Override 051 public E next() 052 { 053 return delegateIterator.previous(); 054 } 055 056 @Override 057 public void remove() 058 { 059 throw new UnsupportedOperationException(); 060 } 061 062 @Override 063 public Iterator<E> iterator() 064 { 065 return this; 066 } 067 068}