1 files changed, 126 insertions, 0 deletions
diff --git a/qpid/java/broker/src/main/java/org/apache/qpid/server/filter/XPathExpression.java b/qpid/java/broker/src/main/java/org/apache/qpid/server/filter/XPathExpression.java
new file mode 100644
index 0000000000..aa35cb5a76
--- /dev/null
+++ b/qpid/java/broker/src/main/java/org/apache/qpid/server/filter/XPathExpression.java
@@ -0,0 +1,126 @@
+/**
+ *
+ * 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 org.apache.log4j.Logger;
+import org.apache.qpid.AMQException;
+import org.apache.qpid.server.queue.Filterable;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+
+/**
+ * Used to evaluate an XPath Expression in a JMS selector.
+ */
+public final class XPathExpression implements BooleanExpression {
+
+    private static final Logger log = Logger.getLogger(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(Filterable message);
+    }
+
+    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(Filterable message)  {
+//        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 AMQException
+     */
+    public boolean matches(Filterable message)
+    {
+        Object object = evaluate(message);
+        return object!=null && object==Boolean.TRUE;
+    }
+
+}