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From cobrien <clark.obr...@ttmsolutions.com>
Subject Re: ActiveMQ mixes up order of messages while receiving them from Camel
Date Thu, 01 Jul 2010 15:47:52 GMT

Great, 
If the list can be large you may want to optimize by making the  commit 
independent of the size of the list. 

Clark 

www.ttmsolutions.com 
ActiveMQ reference guide at 
http://bit.ly/AMQRefGuide


ps
And thanks for sharing your code with the community.


sonicBasher wrote:
> 
> Hi Clark,
> 
> I solved my problem using transactions. Here's how I did it, maybe it'll
> help someone who stumbles upon similar problem (you should probably create
> the ActiveMQConnectionFactory and Session stuff elswhere and just pass a
> reference, but I add it here to make things more clear):
> 
> import java.util.List;
> import javax.jms.Connection;
> import javax.jms.JMSException;
> import javax.jms.Message;
> import javax.jms.Queue;
> import javax.jms.Session;
> import org.apache.activemq.ActiveMQConnectionFactory;
> import org.apache.camel.Body;
> import org.apache.camel.Handler;
> import com.thoughtworks.xstream.XStream;
> 
> @Handler
>     public void produce(@Body List listOfMyObj) throws JMSException {
>         ActiveMQConnectionFactory cf = new ActiveMQConnectionFactory();
>         Connection connection = cf.createConnection();
>         connection.start();
>         XStream x = new XStream();
>         List<MyObject> listOfMyObjects = (List<MyObject>) listOfMyObj;
>         Session session = connection.createSession(true,
> Session.SESSION_TRANSACTED);
>         String id = listOfMyObjects.get(0).getAccountName();
>         Queue queue = session.createQueue(id);
>         javax.jms.MessageProducer producer =
> session.createProducer(queue);
>         for (int q = 0; q < listOfMyObjects .size(); q++) {
>             MyObject eo = listOfMyObjects .get(q);
>             Message message = session.createTextMessage(x.toXML(eo));
>             producer.send(message);
>             if (q == listOfMyObjects .size() - 1) {
>                 session.commit();
>             }
>         }
>     }
> 
> 
> 
> regards
> 
> 
> 
> 
> 
> cobrien wrote:
>> 
>> Hi,
>> It appears like you are sending messages in async  mode (see link: 
>> http://activemq.apache.org/async-sends.html). Order cannot be guaranteed,
>> even for a single producer, using async mode. So the answer to your
>> question is  yes the sync/async mode can change ordering particularly
>> when  sent over  slow or unreliable networks. 
>> 
>> You also may want to look into using transactions to batch  message
>> sends.
>> The link below has an example Camel configuration.( under connection
>> pooling)
>> 
>> http://camel.apache.org/activemq.html
>> 
>> 
>> Clark 
>> 
>> www.ttmsolutions.com 
>> ActiveMQ reference guide at 
>> http://bit.ly/AMQRefGuide
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>>  
>> 
>> 
>> 
>> 
>> 
>> 
>> sonicBasher wrote:
>>> 
>>> Hi Clark,
>>> 
>>> I'm using Client-Server topology, meaning I just access ActiveMQ via
>>> tcp. I do it like this:
>>> 
>>> final String brokerURL = "tcp://localhost:61616";
>>> ConnectionFactory connectionFactory = new
>>> ActiveMQConnectionFactory(brokerURL);
>>> context.addComponent("jms",
>>> JmsComponent.jmsComponentAutoAcknowledge(connectionFactory));
>>> 
>>> where context is obviously my DefaultCamelContext object.
>>> 
>>> As for the config files, I haven't changed anything. My activemq.xml
>>> looks like this:
>>> 
>>> 
>>> 
>>> <!--
>>>     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.
>>> -->
>>> <beans
>>>   xmlns="http://www.springframework.org/schema/beans"
>>>   xmlns:amq="http://activemq.apache.org/schema/core"
>>>   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>>>   xsi:schemaLocation="http://www.springframework.org/schema/beans
>>> http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
>>>   http://activemq.apache.org/schema/core
>>> http://activemq.apache.org/schema/core/activemq-core.xsd">
>>> 
>>>     <!-- Allows us to use system properties as variables in this
>>> configuration file -->
>>>     <bean
>>> class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
>>>         <property name="locations">
>>>            
>>> <value>file:${activemq.base}/conf/credentials.properties</value>
>>>         </property>      
>>>     </bean>
>>> 
>>>     <!-- 
>>>         The <broker> element is used to configure the ActiveMQ broker.

>>>     -->
>>>     <broker xmlns="http://activemq.apache.org/schema/core"
>>> brokerName="localhost" dataDirectory="${activemq.base}/data"
>>> destroyApplicationContextOnStop="true">
>>>  
>>>         <!--
>>> 			For better performances use VM cursor and small memory limit.
>>> 			For more information, see:
>>>             
>>>             http://activemq.apache.org/message-cursors.html
>>>             
>>>             Also, if your producer is "hanging", it's probably due to
>>> producer flow control.
>>>             For more information, see:
>>>             http://activemq.apache.org/producer-flow-control.html
>>>         -->
>>>               
>>>         <destinationPolicy>
>>>             <policyMap>
>>>               <policyEntries>
>>>                 <policyEntry topic=">" producerFlowControl="true"
>>> memoryLimit="1mb">
>>>                   <pendingSubscriberPolicy>
>>>                     <vmCursor />
>>>                   </pendingSubscriberPolicy>
>>>                 </policyEntry>
>>>                 <policyEntry queue=">" producerFlowControl="true"
>>> memoryLimit="1mb">
>>>                   <!-- Use VM cursor for better latency
>>>                        For more information, see:
>>>                        
>>>                        http://activemq.apache.org/message-cursors.html
>>>                        
>>>                   <pendingQueuePolicy>
>>>                     <vmQueueCursor/>
>>>                   </pendingQueuePolicy>
>>>                   -->
>>>                 </policyEntry>
>>>               </policyEntries>
>>>             </policyMap>
>>>         </destinationPolicy> 
>>>  
>>>         
>>>         <!-- 
>>>             The managementContext is used to configure how ActiveMQ is
>>> exposed in 
>>>             JMX. By default, ActiveMQ uses the MBean server that is
>>> started by 
>>>             the JVM. For more information, see: 
>>>             
>>>             http://activemq.apache.org/jmx.html 
>>>         -->
>>>         <managementContext>
>>>             <managementContext createConnector="false"/>
>>>         </managementContext>
>>> 
>>>         <!-- 
>>>             Configure message persistence for the broker. The default
>>> persistence
>>>             mechanism is the KahaDB store (identified by the kahaDB
>>> tag). 
>>>             For more information, see: 
>>>             
>>>             http://activemq.apache.org/persistence.html 
>>>         -->
>>>         <persistenceAdapter>
>>>             <kahaDB directory="${activemq.base}/data/kahadb"/>
>>>         </persistenceAdapter>
>>>         
>>>         
>>>           <!--
>>>             The systemUsage controls the maximum amount of space the
>>> broker will 
>>>             use before slowing down producers. For more information,
>>> see:
>>>             
>>>             http://activemq.apache.org/producer-flow-control.html
>>>              
>>>         <systemUsage>
>>>             <systemUsage>
>>>                 <memoryUsage>
>>>                     <memoryUsage limit="20 mb"/>
>>>                 </memoryUsage>
>>>                 <storeUsage>
>>>                     <storeUsage limit="1 gb" name="foo"/>
>>>                 </storeUsage>
>>>                 <tempUsage>
>>>                     <tempUsage limit="100 mb"/>
>>>                 </tempUsage>
>>>             </systemUsage>
>>>         </systemUsage>
>>> 		-->
>>> 		  
>>>         <!-- 
>>>             The transport connectors expose ActiveMQ over a given
>>> protocol to
>>>             clients and other brokers. For more information, see: 
>>>             
>>>             http://activemq.apache.org/configuring-transports.html 
>>>         -->
>>>         <transportConnectors>
>>>             <transportConnector name="openwire"
>>> uri="tcp://0.0.0.0:61616"/>
>>>         </transportConnectors>
>>> 
>>>     </broker>
>>> 
>>>     <!-- 
>>>         Uncomment to enable Camel
>>>         Take a look at activemq-camel.xml for more details
>>>          
>>>     <import resource="camel.xml"/>
>>>     -->
>>> 
>>>     <!-- 
>>>         Enable web consoles, REST and Ajax APIs and demos
>>>         Take a look at activemq-jetty.xml for more details 
>>>     -->
>>>     <import resource="jetty.xml"/>
>>>     
>>> </beans>
>>> 
>>> 
>>> 
>>> I tried to enable camel in activemq.xml by uncommenting the  <import
>>> resource="camel.xml"/> line, but it doesn't seem to help either - still
>>> getting mixed up messages.
>>> My camel.xml looks like that:
>>> 
>>> 
>>> 
>>> <!--
>>>     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.
>>> -->
>>> <!-- 
>>> 
>>>     Lets deploy some Enterprise Integration Patterns inside the ActiveMQ
>>> Message Broker
>>>     For more information, see:
>>>     
>>>     http://camel.apache.org
>>>     
>>>     Include this file in your configuration to enable Camel
>>>     
>>>     e.g. <import resource="camel.xml"/>
>>> -->
>>> <beans
>>>    xmlns="http://www.springframework.org/schema/beans"  
>>>    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>>>    xsi:schemaLocation="http://camel.apache.org/schema/spring
>>> http://camel.apache.org/schema/spring/camel-spring.xsd
>>>    http://www.springframework.org/schema/beans
>>> http://www.springframework.org/schema/beans/spring-beans.xsd">
>>>   
>>>   	<camelContext id="camel"
>>> xmlns="http://camel.apache.org/schema/spring">
>>> 
>>>         <!-- You can use a <packages> element for each root package
to
>>> search for Java routes -->
>>>         <packageScan>
>>>            <package>org.foo.bar</package>
>>>         </packageScan>
>>> 
>>>         <!-- You can use Spring XML syntax to define the routes here
>>> using the <route> element -->
>>>         <route>
>>>             <from uri="activemq:example.A"/>
>>>             <to uri="activemq:example.B"/>
>>>         </route>
>>>     </camelContext>
>>> 
>>>     <!--
>>>        Lets configure some Camel endpoints
>>>     
>>>        http://camel.apache.org/components.html
>>>     -->
>>> 
>>>     <!-- configure the camel activemq component to use the current
>>> broker -->
>>>     <bean id="activemq"
>>> class="org.apache.activemq.camel.component.ActiveMQComponent" >
>>>        <property name="userName" value="${activemq.username}"/>
>>>        <property name="password" value="${activemq.password}"/>
>>>     </bean>
>>> </beans>
>>> 
>>> 
>>> 
>>> I'm not sure if any other config files might have impact on what is
>>> going on in my case. If yes, please do let me know.
>>> 
>>> regards
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> cobrien wrote:
>>>> 
>>>> Hi,
>>>> Can you describe a little more your Queue topology and configuration-
>>>> perhaps even share your config file(s). Not all queue topologies are
>>>> order preserving!
>>>> -clark
>>>> 
>>>> Clark 
>>>> 
>>>> www.ttmsolutions.com 
>>>> ActiveMQ reference guide at 
>>>> http://bit.ly/AMQRefGuide
>>>> 
>>>> 
>>>> sonicBasher wrote:
>>>>> 
>>>>> At the end of my camel route I have a following class which I use to
>>>>> put messages in ActiveMQ: 
>>>>> 
>>>>> public class MessageProducer { 
>>>>> 
>>>>>     private ProducerTemplate template = null; 
>>>>> 
>>>>>     public MessageProducer(ProducerTemplate template) { 
>>>>>         this.template = template; 
>>>>>     } 
>>>>> 
>>>>>     public void produce(@Body List listOfEttexObj) { 
>>>>>         System.out.println("Entered produce() method"); 
>>>>>         XStream x = new XStream(); 
>>>>>         List<EttexObject> listOfEttexObjects =
>>>>> (List<EttexObject>)listOfEttexObj; 
>>>>>         for (int q = 0; q < listOfEttexObjects.size(); q++) { 
>>>>>             EttexObject eo = listOfEttexObjects.get(q); 
>>>>>             template.sendBody("jms:" + eo.getAccountName() +
>>>>> "_2",x.toXML(eo)); 
>>>>>             System.out.println("Sent type: " +
>>>>> eo.getMessage().getType()); 
>>>>>         } 
>>>>>     } 
>>>>> } 
>>>>> 
>>>>> 
>>>>> *XStream is just a library for converting objects to XML, has nothing
>>>>> to do with anything
>>>>> **EttexObject is my POJO class 
>>>>> 
>>>>> Now, I noticed that whenever I send objects (from the list passed as
>>>>> an argument) to the queues, which I implicitly create using
>>>>> ProducerTemplate, most of the time the order of delivered messages is
>>>>> correct, but there's always one queue, which gets the mixed up
>>>>> messages. I can't really figure out why. I tried to use the
>>>>> requestBody method, instead of sendBody, to no avail. I also double
>>>>> checked the lists that come in - the order of objects inside them is
>>>>> fine. Honestly I'm kind of stuck here. Will be grateful for any tips.

>>>>> 
>>>>> regards 
>>>>> 
>>>>> p.s. Can synchronous/asynchronous ActiveMQ mode have anything to do
>>>>> with my problem? 
>>>>> 
>>>> 
>>>> 
>>> 
>>> 
>> 
>> 
> 
> 

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