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    import javax.xml.xpath.XPathConstants;
029    import javax.xml.xpath.XPathFactory;
030    
031    import org.w3c.dom.Document;
032    import org.w3c.dom.traversal.NodeIterator;
033    import org.xml.sax.InputSource;
034    
035    import org.apache.activemq.command.Message;
036    import org.apache.activemq.util.ByteArrayInputStream;
037    import org.apache.xpath.CachedXPathAPI;
038    import org.apache.xpath.objects.XObject;
039    
040    public class XalanXPathEvaluator implements XPathExpression.XPathEvaluator {
041    
042        private static final XPathFactory FACTORY = XPathFactory.newInstance();
043        private final String xpathExpression;
044        private final DocumentBuilder builder;
045        private final XPath xpath = FACTORY.newXPath();
046    
047        public XalanXPathEvaluator(String xpathExpression, DocumentBuilder builder) throws Exception {
048            this.xpathExpression = xpathExpression;
049            if (builder != null) {
050                this.builder = builder;
051            } else {
052                throw new RuntimeException("No document builder available");
053            }
054        }
055    
056        public boolean evaluate(Message m) throws JMSException {
057            if (m instanceof TextMessage) {
058                String text = ((TextMessage)m).getText();
059                return evaluate(text);
060            } else if (m instanceof BytesMessage) {
061                BytesMessage bm = (BytesMessage)m;
062                byte data[] = new byte[(int)bm.getBodyLength()];
063                bm.readBytes(data);
064                return evaluate(data);
065            }
066            return false;
067        }
068    
069        private boolean evaluate(byte[] data) {
070            try {
071    
072                InputSource inputSource = new InputSource(new ByteArrayInputStream(data));
073                Document inputDocument = builder.parse(inputSource);
074                return ((Boolean) xpath.evaluate(xpathExpression, inputDocument, XPathConstants.BOOLEAN)).booleanValue();
075            } catch (Exception e) {
076                return false;
077            }
078        }
079    
080        private boolean evaluate(String text) {
081            try {
082                InputSource inputSource = new InputSource(new StringReader(text));
083                Document inputDocument = builder.parse(inputSource);
084                return ((Boolean) xpath.evaluate(xpathExpression, inputDocument, XPathConstants.BOOLEAN)).booleanValue();
085            } catch (Exception e) {
086                return false;
087            }
088        }
089    
090        @Override
091        public String toString() {
092            return xpathExpression;
093        }
094    }