001/* 002 * Copyright 2013 The Apache Software Foundation. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016package org.apache.commons.collections4.iterators; 017 018import java.util.Iterator; 019import java.util.NoSuchElementException; 020 021import org.w3c.dom.Node; 022import org.w3c.dom.NodeList; 023 024/** 025 * An {@link Iterator} over a {@link NodeList}. 026 * <p> 027 * This iterator does not support {@link #remove()} as a {@link NodeList} does not support 028 * removal of items. 029 * 030 * @since 4.0 031 * @see NodeList 032 */ 033public class NodeListIterator implements Iterator<Node> { 034 035 /** the original NodeList instance */ 036 private final NodeList nodeList; 037 /** The current iterator index */ 038 private int index = 0; 039 040 /** 041 * Convenience constructor, which creates a new NodeListIterator from 042 * the specified node's childNodes. 043 * 044 * @param node Node, who's child nodes are wrapped by this class. Must not be null 045 * @throws NullPointerException if node is null 046 */ 047 public NodeListIterator(final Node node) { 048 if (node == null) { 049 throw new NullPointerException("Node must not be null."); 050 } 051 this.nodeList = node.getChildNodes(); 052 } 053 054 /** 055 * Constructor, that creates a new NodeListIterator from the specified 056 * <code>org.w3c.NodeList</code> 057 * 058 * @param nodeList node list, which is wrapped by this class. Must not be null 059 * @throws NullPointerException if nodeList is null 060 */ 061 public NodeListIterator(final NodeList nodeList) { 062 if (nodeList == null) { 063 throw new NullPointerException("NodeList must not be null."); 064 } 065 this.nodeList = nodeList; 066 } 067 068 @Override 069 public boolean hasNext() { 070 return nodeList != null && index < nodeList.getLength(); 071 } 072 073 @Override 074 public Node next() { 075 if (nodeList != null && index < nodeList.getLength()) { 076 return nodeList.item(index++); 077 } 078 throw new NoSuchElementException("underlying nodeList has no more elements"); 079 } 080 081 /** 082 * Throws {@link UnsupportedOperationException}. 083 * 084 * @throws UnsupportedOperationException always 085 */ 086 @Override 087 public void remove() { 088 throw new UnsupportedOperationException("remove() method not supported for a NodeListIterator."); 089 } 090}