first cut at resolution to: https://issues.apache.org/activemq/browse/AMQ-2753 - add priority network consumer dispatch policy that will ignore duplicates such that there can be redundancy in the network with the addition of suppressDuplicateTopicSubscriptions attribute on a network bridge

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@948911 13f79535-47bb-0310-9956-ffa450edef68

activemq-core/src/main/java/org/apache/activemq/broker/region/policy/PriorityNetworkDispatchPolicy.java

@@ -0,0 +1,98 @@
+/**
+ * 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.broker.region.policy;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.activemq.broker.region.MessageReference;
+import org.apache.activemq.broker.region.Subscription;
+import org.apache.activemq.command.ConsumerId;
+import org.apache.activemq.command.ConsumerInfo;
+import org.apache.activemq.filter.MessageEvaluationContext;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * dispatch policy that ignores lower priority duplicate network consumers,
+ * used in conjunction with network bridge suppresDuplicateTopicSubscriptions
+ * 
+ * @org.apache.xbean.XBean
+ */
+public class PriorityNetworkDispatchPolicy extends SimpleDispatchPolicy {
+
+    private static final Log LOG = LogFactory.getLog(PriorityNetworkDispatchPolicy.class);
+    @Override
+    public boolean dispatch(MessageReference node,
+            MessageEvaluationContext msgContext,
+            List<Subscription> consumers) throws Exception {
+        
+        List<Subscription> duplicateFreeSubs = new ArrayList<Subscription>();
+        synchronized (consumers) {
+            for (Subscription sub: consumers) {
+                ConsumerInfo info = sub.getConsumerInfo();
+                if (info.isNetworkSubscription()) {    
+                    boolean highestPrioritySub = true;
+                    for (Subscription candidate: duplicateFreeSubs) {
+                        if (matches(candidate, info)) {
+                            if (hasLowerPriority(candidate, info)) {
+                                duplicateFreeSubs.remove(candidate);
+                            } else {
+                                // higher priority matching sub exists
+                                highestPrioritySub = false;
+                                if (LOG.isDebugEnabled()) {
+                                LOG.debug("ignoring lower priority: " + candidate 
+                                        + "[" +candidate.getConsumerInfo().getNetworkConsumerIds() +", "
+                                        + candidate.getConsumerInfo().getNetworkConsumerIds() +"] in favour of: " 
+                                        + sub
+                                        + "[" +sub.getConsumerInfo().getNetworkConsumerIds() +", "
+                                        + sub.getConsumerInfo().getNetworkConsumerIds() +"]");
+                                }
+                            }
+                        }
+                    }
+                    if (highestPrioritySub) {
+                        duplicateFreeSubs.add(sub);
+                    } 
+                } else {
+                    duplicateFreeSubs.add(sub);
+                }
+            }
+        }
+        
+        return super.dispatch(node, msgContext, duplicateFreeSubs);
+    }
+
+    private boolean hasLowerPriority(Subscription candidate,
+            ConsumerInfo info) {
+       return candidate.getConsumerInfo().getPriority() < info.getPriority();
+    }
+
+    private boolean matches(Subscription candidate, ConsumerInfo info) {
+        boolean matched = false;
+        for (ConsumerId candidateId: candidate.getConsumerInfo().getNetworkConsumerIds()) {
+            for (ConsumerId subId: info.getNetworkConsumerIds()) {
+                if (candidateId.equals(subId)) {
+                    matched = true;
+                    break;
+                }
+            }
+        }
+        return matched;
+    }
+
+}

activemq-core/src/main/java/org/apache/activemq/network/DemandForwardingBridgeSupport.java

@@ -1020,7 +1020,8 @@ public abstract class DemandForwardingBridgeSupport implements NetworkBridge, Br
         final ConsumerInfo consumerInfo = candidate.getRemoteInfo();
         boolean suppress = false;
 
-        if (consumerInfo.getDestination().isQueue() && !configuration.isSuppressDuplicateQueueSubscriptions()) {
+        if (consumerInfo.getDestination().isQueue() && !configuration.isSuppressDuplicateQueueSubscriptions() ||
+                consumerInfo.getDestination().isTopic() && !configuration.isSuppressDuplicateTopicSubscriptions()) {
             return suppress;
         }
 

activemq-core/src/main/java/org/apache/activemq/network/NetworkBridgeConfiguration.java

@@ -46,6 +46,7 @@ public class NetworkBridgeConfiguration {
     private List<ActiveMQDestination> staticallyIncludedDestinations;
 
     private boolean suppressDuplicateQueueSubscriptions = false;
+    private boolean suppressDuplicateTopicSubscriptions = true;
 
 
     /**
@@ -275,6 +276,18 @@ public class NetworkBridgeConfiguration {
         suppressDuplicateQueueSubscriptions = val;
     }
 
+    public boolean isSuppressDuplicateTopicSubscriptions() {
+        return suppressDuplicateTopicSubscriptions;
+    }
+
+    /**
+     * 
+     * @param val if true, duplicate network topic subscriptions (in a cyclic network) will be suppressed
+     */
+    public void setSuppressDuplicateTopicSubscriptions(boolean val) {
+        suppressDuplicateTopicSubscriptions  = val;
+    }
+    
     /**
      * @return the brokerURL
      */

activemq-core/src/test/java/org/apache/activemq/usecases/NoDuplicateOnTopicNetworkTest.java

@@ -18,6 +18,7 @@ package org.apache.activemq.usecases;
 
 import java.net.URI;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -34,16 +35,23 @@ import javax.jms.Session;
 import javax.jms.TextMessage;
 import javax.jms.Topic;
 
-import junit.framework.TestCase;
+import junit.framework.Test;
 
 import org.apache.activemq.ActiveMQConnectionFactory;
+import org.apache.activemq.CombinationTestSupport;
 import org.apache.activemq.broker.BrokerService;
+import org.apache.activemq.broker.region.policy.DispatchPolicy;
+import org.apache.activemq.broker.region.policy.PolicyEntry;
+import org.apache.activemq.broker.region.policy.PolicyMap;
+import org.apache.activemq.broker.region.policy.PriorityNetworkDispatchPolicy;
+import org.apache.activemq.broker.region.policy.SimpleDispatchPolicy;
+import org.apache.activemq.command.ActiveMQTopic;
 import org.apache.activemq.network.NetworkConnector;
 import org.apache.activemq.util.Wait;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
-public class NoDuplicateOnTopicNetworkTest extends TestCase {
+public class NoDuplicateOnTopicNetworkTest extends CombinationTestSupport {
     private static final Log LOG = LogFactory
             .getLog(NoDuplicateOnTopicNetworkTest.class);
 
@@ -51,17 +59,23 @@ public class NoDuplicateOnTopicNetworkTest extends TestCase {
     private static final String BROKER_1 = "tcp://localhost:61626";
     private static final String BROKER_2 = "tcp://localhost:61636";
     private static final String BROKER_3 = "tcp://localhost:61646";
+    private final static String TOPIC_NAME = "broadcast";
     private BrokerService broker1;
     private BrokerService broker2;
     private BrokerService broker3;
 
+    public boolean suppressDuplicateTopicSubs = false;
+    public DispatchPolicy dispatchPolicy = new SimpleDispatchPolicy();
+    
     private boolean dynamicOnly = false;
     // no duplicates in cyclic network if networkTTL <=1
     // when > 1, subscriptions perculate around resulting in duplicates as there is no
     // memory of the original subscription.
     // solution for 6.0 using org.apache.activemq.command.ConsumerInfo.getNetworkConsumerIds()
     private int ttl = 3;
-
+    
+    
+  
     @Override
     protected void setUp() throws Exception {
         super.setUp();
@@ -76,6 +90,10 @@ public class NoDuplicateOnTopicNetworkTest extends TestCase {
         waitForBridgeFormation();
     }
     
+    public static Test suite() {
+        return suite(NoDuplicateOnTopicNetworkTest.class);
+    }
+    
     protected void waitForBridgeFormation() throws Exception {
         Wait.waitFor(new Wait.Condition() {
             public boolean isSatisified() throws Exception {
@@ -105,7 +123,17 @@ public class NoDuplicateOnTopicNetworkTest extends TestCase {
         networkConnector.setDecreaseNetworkConsumerPriority(true);
         networkConnector.setDynamicOnly(dynamicOnly);
         networkConnector.setNetworkTTL(ttl);
+        networkConnector.setSuppressDuplicateTopicSubscriptions(suppressDuplicateTopicSubs);
 
+        
+        PolicyMap policyMap = new PolicyMap();
+        PolicyEntry policy = new PolicyEntry();
+        policy.setDispatchPolicy(dispatchPolicy);
+        // the audit will suppress the duplicates as it defaults to true so this test
+        // checking for dups will fail. it is good to have it on in practice.
+        policy.setEnableAudit(false);
+        policyMap.put(new ActiveMQTopic(TOPIC_NAME), policy);
+        broker.setDestinationPolicy(policyMap);
         broker.start();
        
         return broker;
@@ -119,13 +147,20 @@ public class NoDuplicateOnTopicNetworkTest extends TestCase {
         super.tearDown();
     }
 
+    public void initCombosForTestProducerConsumerTopic() {
+        this.addCombinationValues("suppresDuplicateTopicSubs", new Object[]{Boolean.TRUE, Boolean.FALSE});
+        this.addCombinationValues("dispatchPolicy", new Object[]{new PriorityNetworkDispatchPolicy(), new SimpleDispatchPolicy()});
+    }
+    
     public void testProducerConsumerTopic() throws Exception {
-        final String topicName = "broadcast";
+        
+        final CountDownLatch consumerStarted = new CountDownLatch(1);
+        
         Thread producerThread = new Thread(new Runnable() {
             public void run() {
                 TopicWithDuplicateMessages producer = new TopicWithDuplicateMessages();
                 producer.setBrokerURL(BROKER_1);
-                producer.setTopicName(topicName);
+                producer.setTopicName(TOPIC_NAME);
                 try {
                     producer.produce();
                 } catch (JMSException e) {
@@ -138,9 +173,10 @@ public class NoDuplicateOnTopicNetworkTest extends TestCase {
         Thread consumerThread = new Thread(new Runnable() {
             public void run() {
                 consumer.setBrokerURL(BROKER_2);
-                consumer.setTopicName(topicName);
+                consumer.setTopicName(TOPIC_NAME);
                 try {
                     consumer.consumer();
+                    consumerStarted.countDown();
                     consumer.getLatch().await(60, TimeUnit.SECONDS);
                 } catch (Exception e) {
                     fail("Unexpected " + e);
@@ -151,20 +187,32 @@ public class NoDuplicateOnTopicNetworkTest extends TestCase {
         consumerThread.start();
         LOG.info("Started Consumer");
         
+        assertTrue("consumer started eventually", consumerStarted.await(10, TimeUnit.SECONDS));
+        
         // ensure subscription has percolated though the network
         Thread.sleep(2000);
+        
         producerThread.start();
         LOG.info("Started Producer");
         producerThread.join();
         consumerThread.join();
 
+        int duplicateCount = 0;
         Map<String, String> map = new HashMap<String, String>();
         for (String msg : consumer.getMessageStrings()) {
-            assertTrue("is not a duplicate: " + msg, !map.containsKey(msg));
+            if (map.containsKey(msg)) {
+                LOG.info("got duplicate: " + msg);
+                duplicateCount++;
+            }
             map.put(msg, msg);
         }
-        assertEquals("got all required messages: " + map.size(), consumer
+        if (suppressDuplicateTopicSubs || dispatchPolicy instanceof PriorityNetworkDispatchPolicy) {
-                .getNumMessages(), map.size());
+            assertEquals("no duplicates", 0, duplicateCount);
+            assertEquals("got all required messages: " + map.size(), consumer
+                    .getNumMessages(), map.size());
+        } else {
+            assertTrue("we got some duplicates", duplicateCount > 0);
+        }
     }
 
     class TopicWithDuplicateMessages {
@@ -176,16 +224,18 @@ public class NoDuplicateOnTopicNetworkTest extends TestCase {
         private MessageProducer producer;
         private MessageConsumer consumer;
 
-        private List<String> receivedStrings = new ArrayList<String>();
+        private List<String> receivedStrings = Collections.synchronizedList(new ArrayList<String>());
         private int numMessages = 10;
         private CountDownLatch recievedLatch = new CountDownLatch(numMessages);
 
         public CountDownLatch getLatch() {
             return recievedLatch;
         }
-
+        
         public List<String> getMessageStrings() {
-            return receivedStrings;
+            synchronized(receivedStrings) {
+                return new ArrayList<String>(receivedStrings);
+            }
         }
 
         public String getBrokerURL() {