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 */
017
018 package org.apache.activemq.filter;
019
020 import java.io.StringReader;
021
022 import javax.jms.BytesMessage;
023 import javax.jms.JMSException;
024 import javax.jms.TextMessage;
025 import javax.xml.parsers.DocumentBuilder;
026 import javax.xml.parsers.DocumentBuilderFactory;
027 import javax.xml.xpath.XPath;
028
029 import org.w3c.dom.Document;
030 import org.w3c.dom.traversal.NodeIterator;
031 import org.xml.sax.InputSource;
032
033 import org.apache.activemq.command.Message;
034 import org.apache.activemq.util.ByteArrayInputStream;
035 import org.apache.xpath.CachedXPathAPI;
036 import org.apache.xpath.objects.XObject;
037
038
039 public class XalanXPathEvaluator implements XPathExpression.XPathEvaluator {
040
041 private final String xpath;
042
043 public XalanXPathEvaluator(String xpath) {
044 this.xpath = xpath;
045 }
046
047 public boolean evaluate(Message m) throws JMSException {
048 if (m instanceof TextMessage) {
049 String text = ((TextMessage)m).getText();
050 return evaluate(text);
051 } else if (m instanceof BytesMessage) {
052 BytesMessage bm = (BytesMessage)m;
053 byte data[] = new byte[(int)bm.getBodyLength()];
054 bm.readBytes(data);
055 return evaluate(data);
056 }
057 return false;
058 }
059
060 private boolean evaluate(byte[] data) {
061 try {
062
063 InputSource inputSource = new InputSource(new ByteArrayInputStream(data));
064
065 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
066 factory.setNamespaceAware(true);
067 DocumentBuilder dbuilder = factory.newDocumentBuilder();
068 Document doc = dbuilder.parse(inputSource);
069
070 CachedXPathAPI cachedXPathAPI = new CachedXPathAPI();
071 XObject result = cachedXPathAPI.eval(doc, xpath);
072 if (result.bool())
073 return true;
074 else {
075 NodeIterator iterator = cachedXPathAPI.selectNodeIterator(doc, xpath);
076 return (iterator.nextNode() != null);
077 }
078
079 } catch (Throwable e) {
080 return false;
081 }
082 }
083
084 private boolean evaluate(String text) {
085 try {
086 InputSource inputSource = new InputSource(new StringReader(text));
087
088 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
089 factory.setNamespaceAware(true);
090 DocumentBuilder dbuilder = factory.newDocumentBuilder();
091 Document doc = dbuilder.parse(inputSource);
092
093 //An XPath expression could return a true or false value instead of a node.
094 //eval() is a better way to determine the boolean value of the exp.
095 //For compliance with legacy behavior where selecting an empty node returns true,
096 //selectNodeIterator is attempted in case of a failure.
097
098 CachedXPathAPI cachedXPathAPI = new CachedXPathAPI();
099 XObject result = cachedXPathAPI.eval(doc, xpath);
100 if (result.bool())
101 return true;
102 else {
103 NodeIterator iterator = cachedXPathAPI.selectNodeIterator(doc, xpath);
104 return (iterator.nextNode() != null);
105 }
106
107 } catch (Throwable e) {
108 return false;
109 }
110 }
111 }