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.camel.converter.jaxp; 018 019import java.util.ArrayList; 020import java.util.List; 021 022import org.w3c.dom.Document; 023import org.w3c.dom.Node; 024import org.w3c.dom.NodeList; 025import org.w3c.dom.Text; 026 027/** 028 * A simple thread-safe {@link NodeList} that is used by {@link org.apache.camel.builder.xml.XPathBuilder} 029 * to return thread-safe {@link NodeList} instances as its result. 030 * <p/> 031 * This is needed to ensure that end users do not hit any concurrency issues while working 032 * with xpath expressions using built-in from the JDK or via camel-saxon. 033 */ 034public class ThreadSafeNodeList implements NodeList { 035 036 private final List<Node> list = new ArrayList<>(); 037 038 public ThreadSafeNodeList(NodeList source) throws Exception { 039 init(source); 040 } 041 042 @Override 043 public Node item(int index) { 044 return list.get(index); 045 } 046 047 @Override 048 public int getLength() { 049 return list.size(); 050 } 051 052 private void init(NodeList source) throws Exception { 053 for (int i = 0; i < source.getLength(); i++) { 054 Node node = source.item(i); 055 if (node != null) { 056 // import node must not occur concurrent on the same node (must be its owner) 057 // so we need to synchronize on it 058 synchronized (node.getOwnerDocument()) { 059 Document doc = new XmlConverter().createDocument(); 060 // import node must not occur concurrent on the same node (must be its owner) 061 // so we need to synchronize on it 062 synchronized (node.getOwnerDocument()) { 063 Node clone = doc.importNode(node, true); 064 if (clone instanceof Text) { 065 // basic text node then add as-is 066 list.add(clone); 067 } else { 068 // more complex node, then add as child (yes its a bit weird but this is working) 069 doc.appendChild(clone); 070 list.add(doc.getChildNodes().item(0)); 071 } 072 } 073 } 074 } 075 } 076 } 077 078}