diff options
Diffstat (limited to 'java/broker/src/main/java/org/apache/qpid/server/filter/XPathExpression.java')
-rw-r--r-- | java/broker/src/main/java/org/apache/qpid/server/filter/XPathExpression.java | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/java/broker/src/main/java/org/apache/qpid/server/filter/XPathExpression.java b/java/broker/src/main/java/org/apache/qpid/server/filter/XPathExpression.java new file mode 100644 index 0000000000..ab952b6fea --- /dev/null +++ b/java/broker/src/main/java/org/apache/qpid/server/filter/XPathExpression.java @@ -0,0 +1,130 @@ +/** + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.qpid.server.filter; +// +// Based on like named file from r450141 of the Apache ActiveMQ project <http://www.activemq.org/site/home.html> +// + +import java.io.IOException; +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; + +import javax.jms.JMSException; + +//import org.apache.activemq.command.Message; +//import org.apache.activemq.util.JMSExceptionSupport; +import org.apache.commons.logging.Log; +import org.apache.commons.logging.LogFactory; +import org.apache.qpid.server.queue.AMQMessage; + +/** + * Used to evaluate an XPath Expression in a JMS selector. + */ +public final class XPathExpression implements BooleanExpression { + + private static final Log log = LogFactory.getLog(XPathExpression.class); + private static final String EVALUATOR_SYSTEM_PROPERTY = "org.apache.qpid.server.filter.XPathEvaluatorClassName"; + private static final String DEFAULT_EVALUATOR_CLASS_NAME=XalanXPathEvaluator.class.getName(); + + private static final Constructor EVALUATOR_CONSTRUCTOR; + + static { + String cn = System.getProperty(EVALUATOR_SYSTEM_PROPERTY, DEFAULT_EVALUATOR_CLASS_NAME); + Constructor m = null; + try { + try { + m = getXPathEvaluatorConstructor(cn); + } catch (Throwable e) { + log.warn("Invalid "+XPathEvaluator.class.getName()+" implementation: "+cn+", reason: "+e,e); + cn = DEFAULT_EVALUATOR_CLASS_NAME; + try { + m = getXPathEvaluatorConstructor(cn); + } catch (Throwable e2) { + log.error("Default XPath evaluator could not be loaded",e); + } + } + } finally { + EVALUATOR_CONSTRUCTOR = m; + } + } + + private static Constructor getXPathEvaluatorConstructor(String cn) throws ClassNotFoundException, SecurityException, NoSuchMethodException { + Class c = XPathExpression.class.getClassLoader().loadClass(cn); + if( !XPathEvaluator.class.isAssignableFrom(c) ) { + throw new ClassCastException(""+c+" is not an instance of "+XPathEvaluator.class); + } + return c.getConstructor(new Class[]{String.class}); + } + + private final String xpath; + private final XPathEvaluator evaluator; + + static public interface XPathEvaluator { + public boolean evaluate(AMQMessage message) throws JMSException; + } + + XPathExpression(String xpath) { + this.xpath = xpath; + this.evaluator = createEvaluator(xpath); + } + + private XPathEvaluator createEvaluator(String xpath2) { + try { + return (XPathEvaluator)EVALUATOR_CONSTRUCTOR.newInstance(new Object[]{xpath}); + } catch (InvocationTargetException e) { + Throwable cause = e.getCause(); + if( cause instanceof RuntimeException ) { + throw (RuntimeException)cause; + } + throw new RuntimeException("Invalid XPath Expression: "+xpath+" reason: "+e.getMessage(), e); + } catch (Throwable e) { + throw new RuntimeException("Invalid XPath Expression: "+xpath+" reason: "+e.getMessage(), e); + } + } + + public Object evaluate(AMQMessage message) throws JMSException { +// try { +//FIXME this is flow to disk work +// if( message.isDropped() ) +// return null; + return evaluator.evaluate(message) ? Boolean.TRUE : Boolean.FALSE; +// } catch (IOException e) { +// +// JMSException exception = new JMSException(e.getMessage()); +// exception.initCause(e); +// throw exception; +// +// } + + } + + public String toString() { + return "XPATH "+ConstantExpression.encodeString(xpath); + } + + /** + * @param message + * @return true if the expression evaluates to Boolean.TRUE. + * @throws JMSException + */ + public boolean matches(AMQMessage message) throws JMSException { + Object object = evaluate(message); + return object!=null && object==Boolean.TRUE; + } + +} |