ARTEMIS-4687 concurrent use of DocumentBuilder breaking Xpath filtering

artemis-selector/pom.xml

@@ -46,7 +46,6 @@
       <dependency>
          <groupId>org.slf4j</groupId>
          <artifactId>slf4j-api</artifactId>
-         <scope>test</scope>
       </dependency>
       <dependency>
          <groupId>org.apache.activemq</groupId>

artemis-selector/src/main/java/org/apache/activemq/artemis/selector/filter/JAXPXPathEvaluator.java

@@ -21,10 +21,14 @@
 import javax.xml.xpath.XPathConstants;
 import javax.xml.xpath.XPathFactory;
 import java.io.StringReader;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.lang.invoke.MethodHandles;
 
 import org.xml.sax.InputSource;
 
 public class JAXPXPathEvaluator implements XPathExpression.XPathEvaluator {
+   private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
 
    // this is not thread-safe https://docs.oracle.com/javase/8/docs/api/javax/xml/xpath/XPathFactory.html
    private static final XPathFactory FACTORY = XPathFactory.newInstance();
@@ -56,8 +60,11 @@ protected boolean evaluate(String text) {
 
    protected boolean evaluate(InputSource inputSource) {
       try {
-         return ((Boolean)xpath.evaluate(xpathExpression, builder.parse(inputSource), XPathConstants.BOOLEAN)).booleanValue();
+         synchronized (builder) {
+            return ((Boolean)xpath.evaluate(xpathExpression, builder.parse(inputSource), XPathConstants.BOOLEAN)).booleanValue();
+         }
       } catch (Exception e) {
+         logger.debug("Failed to evaluate XPath expression {}", xpathExpression, inputSource, e);
          return false;
       }
    }

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/server/ServerFilterTest.java

@@ -0,0 +1,85 @@
+/*
+ * 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.activemq.artemis.tests.integration.server;
+
+import javax.jms.Connection;
+import javax.jms.ConnectionFactory;
+import javax.jms.JMSException;
+import javax.jms.Message;
+import javax.jms.MessageProducer;
+import javax.jms.Session;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import org.apache.activemq.artemis.api.core.QueueConfiguration;
+import org.apache.activemq.artemis.api.core.RoutingType;
+import org.apache.activemq.artemis.api.core.SimpleString;
+import org.apache.activemq.artemis.core.server.ActiveMQServer;
+import org.apache.activemq.artemis.jms.client.ActiveMQConnectionFactory;
+import org.apache.activemq.artemis.jms.client.ActiveMQTopic;
+import org.apache.activemq.artemis.tests.util.ActiveMQTestBase;
+import org.apache.activemq.artemis.tests.util.Wait;
+import org.junit.Before;
+import org.junit.Test;
+
+public class ServerFilterTest extends ActiveMQTestBase {
+
+   private ActiveMQServer server;
+
+   @Override
+   @Before
+   public void setUp() throws Exception {
+      super.setUp();
+      server = createServer(false);
+      server.start();
+   }
+
+   @Test
+   public void concurrentXpathTest() throws Exception {
+      final long threadCount = 5;
+      final long messageCount = 5;
+      final String address = "myAddress";
+      final String xpathFilter = "XPATH '/a/b/c/d[text()=\"foo\"]'";
+      final String text = "<a><b><c><d>foo</d></c></b></a>";
+
+      server.createQueue(new QueueConfiguration("A").setAddress(address).setFilterString(xpathFilter).setRoutingType(RoutingType.MULTICAST));
+      server.createQueue(new QueueConfiguration("B").setAddress(address).setFilterString(xpathFilter).setRoutingType(RoutingType.MULTICAST));
+      ConnectionFactory cf = new ActiveMQConnectionFactory("vm://0");
+      ExecutorService executor = Executors.newFixedThreadPool((int) threadCount);
+      for (int i = 0; i < threadCount; i++) {
+         executor.submit(() -> {
+            try (Connection conn = cf.createConnection()) {
+               Session session = conn.createSession();
+               MessageProducer producer = session.createProducer(new ActiveMQTopic(address));
+               Message msg = session.createTextMessage(text);
+               int count = 0;
+               while (count++ < messageCount) {
+                  msg.setStringProperty("MessageId", String.valueOf(count));
+                  producer.send(msg);
+               }
+               session.close();
+            } catch (JMSException e) {
+               e.printStackTrace();
+            }
+         });
+      }
+      runAfter(executor::shutdownNow);
+      Wait.assertEquals(threadCount * messageCount, () -> server.getAddressInfo(SimpleString.toSimpleString(address)).getRoutedMessageCount(), 2000, 100);
+      Wait.assertEquals(threadCount * messageCount, () -> server.locateQueue("A").getMessageCount(), 2000, 100);
+      Wait.assertEquals(threadCount * messageCount, () -> server.locateQueue("B").getMessageCount(), 2000, 100);
+   }
+}