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    package org.apache.activemq.filter;
018    
019    import java.io.StringReader;
020    
021    import javax.jms.BytesMessage;
022    import javax.jms.JMSException;
023    import javax.jms.TextMessage;
024    import javax.xml.xpath.XPath;
025    import javax.xml.xpath.XPathConstants;
026    import javax.xml.xpath.XPathExpressionException;
027    import javax.xml.xpath.XPathFactory;
028    
029    import org.xml.sax.InputSource;
030    
031    import org.apache.activemq.command.Message;
032    import org.apache.activemq.util.ByteArrayInputStream;
033    
034    public class JAXPXPathEvaluator implements XPathExpression.XPathEvaluator {
035    
036        private static final XPathFactory FACTORY = XPathFactory.newInstance();
037        private javax.xml.xpath.XPathExpression expression;
038    
039        public JAXPXPathEvaluator(String xpathExpression) {
040            try {
041                XPath xpath = FACTORY.newXPath();
042                expression = xpath.compile(xpathExpression);
043            } catch (XPathExpressionException e) {
044                throw new RuntimeException("Invalid XPath expression: " + xpathExpression);
045            }
046        }
047    
048        public boolean evaluate(Message message) throws JMSException {
049            if (message instanceof TextMessage) {
050                String text = ((TextMessage)message).getText();
051                return evaluate(text);
052            } else if (message instanceof BytesMessage) {
053                BytesMessage bm = (BytesMessage)message;
054                byte data[] = new byte[(int)bm.getBodyLength()];
055                bm.readBytes(data);
056                return evaluate(data);
057            }
058            return false;
059        }
060    
061        private boolean evaluate(byte[] data) {
062            try {
063                InputSource inputSource = new InputSource(new ByteArrayInputStream(data));
064                return ((Boolean)expression.evaluate(inputSource, XPathConstants.BOOLEAN)).booleanValue();
065            } catch (XPathExpressionException e) {
066                return false;
067            }
068        }
069    
070        private boolean evaluate(String text) {
071            try {
072                InputSource inputSource = new InputSource(new StringReader(text));
073                return ((Boolean)expression.evaluate(inputSource, XPathConstants.BOOLEAN)).booleanValue();
074            } catch (XPathExpressionException e) {
075                return false;
076            }
077        }
078    }