https://issues.apache.org/jira/browse/AMQ-6000

Fix and test, wakeup queue dispatch when resume is called.

activemq-broker/src/main/java/org/apache/activemq/broker/region/Queue.java

@@ -49,7 +49,13 @@ import javax.jms.ResourceAllocationException;
 import org.apache.activemq.broker.BrokerService;
 import org.apache.activemq.broker.ConnectionContext;
 import org.apache.activemq.broker.ProducerBrokerExchange;
-import org.apache.activemq.broker.region.cursors.*;
+import org.apache.activemq.broker.region.cursors.OrderedPendingList;
+import org.apache.activemq.broker.region.cursors.PendingList;
+import org.apache.activemq.broker.region.cursors.PendingMessageCursor;
+import org.apache.activemq.broker.region.cursors.PrioritizedPendingList;
+import org.apache.activemq.broker.region.cursors.QueueDispatchPendingList;
+import org.apache.activemq.broker.region.cursors.StoreQueueCursor;
+import org.apache.activemq.broker.region.cursors.VMPendingMessageCursor;
 import org.apache.activemq.broker.region.group.CachedMessageGroupMapFactory;
 import org.apache.activemq.broker.region.group.MessageGroupMap;
 import org.apache.activemq.broker.region.group.MessageGroupMapFactory;
@@ -1657,6 +1663,7 @@ public class Queue extends BaseDestination implements Task, UsageListener, Index
 
     public void resumeDispatch() {
         dispatchSelector.resume();
+        wakeup();
     }
 
     public boolean isDispatchPaused() {

activemq-unit-tests/src/test/java/org/apache/activemq/bugs/AMQ6000Test.java

@@ -0,0 +1,138 @@
+/**
+ * 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.bugs;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import javax.jms.Destination;
+import javax.jms.JMSException;
+import javax.jms.MessageConsumer;
+import javax.jms.MessageProducer;
+import javax.jms.Session;
+import javax.management.MalformedObjectNameException;
+import javax.management.ObjectName;
+
+import org.apache.activemq.ActiveMQConnection;
+import org.apache.activemq.ActiveMQConnectionFactory;
+import org.apache.activemq.broker.BrokerService;
+import org.apache.activemq.broker.jmx.QueueViewMBean;
+import org.apache.activemq.broker.region.policy.PolicyEntry;
+import org.apache.activemq.broker.region.policy.PolicyMap;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestName;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Test for AMQ-6000 issue with pause / resume feature.
+ */
+public class AMQ6000Test {
+
+    private static Logger LOG = LoggerFactory.getLogger(AMQ5921Test.class);
+
+    private ActiveMQConnection connection;
+    private BrokerService broker;
+    private String connectionUri;
+
+    @Rule
+    public TestName name = new TestName();
+
+    @Before
+    public void setUp() throws Exception {
+        broker = new BrokerService();
+        broker.setUseJmx(true);
+        broker.setPersistent(false);
+
+        PolicyMap policyMap = new PolicyMap();
+        PolicyEntry defaultEntry = new PolicyEntry();
+        defaultEntry.setExpireMessagesPeriod(0);
+        defaultEntry.setUseCache(false);
+        policyMap.setDefaultEntry(defaultEntry);
+
+        broker.setDestinationPolicy(policyMap);
+        broker.addConnector("tcp://localhost:0");
+        broker.start();
+        broker.waitUntilStarted();
+
+        connectionUri = broker.getTransportConnectors().get(0).getPublishableConnectString();
+
+        connection = createConnection();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        if (connection != null) {
+            try {
+                connection.close();
+            } catch (Exception e) {}
+        }
+
+        if (broker != null) {
+            broker.stop();
+            broker.waitUntilStopped();
+        }
+    }
+
+    @Test(timeout = 30000)
+    public void testResumeNotDispatching() throws Exception {
+        sendMessage();
+
+        connection.start();
+
+        Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
+        Destination destination = session.createQueue(name.getMethodName());
+
+        QueueViewMBean queueView = getProxyToQueue(name.getMethodName());
+        LOG.info("Pausing Queue");
+        queueView.pause();
+
+        MessageConsumer consumer = session.createConsumer(destination);
+        assertNull(consumer.receive(100));
+
+        LOG.info("Resuming Queue");
+        queueView.resume();
+
+        assertNotNull(consumer.receive(2000));
+    }
+
+    protected QueueViewMBean getProxyToQueue(String name) throws MalformedObjectNameException, JMSException {
+        ObjectName queueViewMBeanName = new ObjectName("org.apache.activemq:type=Broker,brokerName=localhost,destinationType=Queue,destinationName="+name);
+        QueueViewMBean proxy = (QueueViewMBean) broker.getManagementContext()
+                .newProxyInstance(queueViewMBeanName, QueueViewMBean.class, true);
+        return proxy;
+    }
+
+    protected ActiveMQConnectionFactory createConnectionFactory() throws Exception {
+        return new ActiveMQConnectionFactory(connectionUri);
+    }
+
+    protected ActiveMQConnection createConnection() throws Exception {
+        return (ActiveMQConnection) createConnectionFactory().createConnection();
+    }
+
+    private void sendMessage() throws Exception {
+        Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
+        Destination destination = session.createQueue(name.getMethodName());
+        MessageProducer producer = session.createProducer(destination);
+        producer.send(session.createMessage());
+        session.close();
+    }
+}