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From Neal Sanche <>
Subject Re: MDB Question
Date Sun, 11 Jun 2006 07:11:39 GMT
Thanks David,

I've looked for the examples you mention, and probably because it's 
late, but I'm not getting it. Let's see if I can follow it at least a 
little. I can't use JNDI, that much is clear. The only thing in the 
GBean's JNDI is the JMXConnector object.

So, you're saying that I can use constructor dependency injection 
instead. So, in my <sys:gbean>, I would have to add a couple of 
<sys:reference> tags, the question is what do I use for the 'name' 
attribute and the <sys:name> child element of those references?

Then, after I've done that, and set up the references in my GBean Info, 
I can set up a constructor that takes those parameters. I've been 
looking at the JDBCStoreThreadPooledNonTransactionalTimer class, which 
shows exactly how to do that. That makes sense.

I guess all I need is direction on what my <sys:gbean> should look like?

 <sys:gbean class="org.acme.TimerGBean" name="TimerGBean">
   <sys:attribute name="period">5000</sys:attribute>
   <sys:reference name="IS THIS RELATED TO THE GBEAN INFO?">
      <sys:name>WHAT IS THIS?</sys:name>

If you could tell me how to figure out the two names, I'll try it and 
see if I get references to my queue and connection factories.



David Jencks wrote:
> Hi Neal,
> This isn't going to work using jndi.  We only supply the spec-required 
> local jndi java:comp context to j2ee components, and there is no 
> global jndi context.  Therefore a gbean with a thread is not going to 
> have a usable jndi context.
> What you can do instead is use gbean references and constructor 
> dependency injection.  This is a bit strange, because the gbeans 
> involved are not queues or connection factories but holders for them, 
> and to get the queue or connection factory you have to call a 
> $getResource method on them.
> For instance, for the connection factory you could include in your 
> gbean into and constuctor args a reference to a 
> ManagedConnectionFactoryWrapper, and get the connection factory by
>   ConnectionFactory connectionFactory = (ConnectionFactory) 
> mcfWrapper.$getResource();
> in your constructor: similarly
>   Queue queue = (Queue) adminObjectWrapper.$getResource();
> If you look in the system-database plan and the timer module you can 
> see an example of this, the timer gbean has a reference to a 
> MCFWrapper gbean and gets the datasource from it.  Activemq journal 
> has a similar reference to get a jdbc datasource for long-term 
> persistence.
> Hope this helps,
> david jencks
> On Jun 10, 2006, at 10:20 PM, Neal Sanche wrote:
>> Hi All,
>> I am doing some research for a Geronimo 1.1 tutorial I'm putting 
>> together. I'm writing a little reminder application that uses an MDB 
>> that is periodically sent a JMS message to wake it up to perform a 
>> little database lookup and send out a bunch of reminder email 
>> messages. That's the theory anyway.
>> I have managed to get my MDB to deploy after creating a JMS Resource 
>> Adaptor through the Admin console, and then setting up the dependency 
>> and MessageDriven section in my open-ejb.xml deployment plan, that 
>> looks like the following:
>> <?xml version="1.0" encoding="UTF-8"?>
>> <openejb-jar xmlns="" 
>> xmlns:nam=""
>>    xmlns:pkgen="" 
>> xmlns:sec=""
>>    xmlns:sys="">
>>  <sys:environment>
>>    <sys:moduleId>
>>      <sys:groupId>default</sys:groupId>
>>      <sys:artifactId>ReminderBackend</sys:artifactId>
>>      <sys:version>1.0</sys:version>
>>      <sys:type>car</sys:type>
>>    </sys:moduleId>
>>    <sys:dependencies>
>>      <sys:dependency>
>>        <sys:groupId>console.jms</sys:groupId>
>>        <sys:artifactId>ReminderMessageAdaptor</sys:artifactId>
>>        <sys:version>1.0</sys:version>
>>        <sys:type>rar</sys:type>
>>      </sys:dependency>
>>    </sys:dependencies>
>>  </sys:environment>
>>  <enterprise-beans>
>>    <message-driven>
>>      <ejb-name>TimerTick</ejb-name>
>>      <nam:resource-adapter>
>>        <nam:resource-link>ReminderMessageAdaptor</nam:resource-link>
>>      </nam:resource-adapter>
>>      <activation-config>
>>        <activation-config-property>
>> <activation-config-property-name>destination</activation-config-property-name>

>> <activation-config-property-value>TimerTickQueue</activation-config-property-value>

>>        </activation-config-property>
>>        <activation-config-property>
>> <activation-config-property-name>destinationType</activation-config-property-name>

>> <activation-config-property-value>javax.jms.Queue</activation-config-property-value>

>>        </activation-config-property>
>>      </activation-config>
>>    </message-driven>
>>  </enterprise-beans>
>> </openejb-jar>
>> Now, that's all good. It deploys without any warnings. Now, I want to 
>> send a message to the queue. So, I thought to myself, 'Self, I'll 
>> write a GBean to start a thread to send a TextMessage to the queue 
>> periodically.' So I wrote one, and added the following to my 
>> deployment descriptor:
>>  <sys:gbean class="org.acme.TimerGBean" name="TimerGBean">
>>    <sys:attribute name="period">5000</sys:attribute>
>>  </sys:gbean>
>> I am getting called back for the start() and stop() lifecycle 
>> methods, and so I wrote my thread to be interruptable, and that's all 
>> working. My thread wakes up and calls the following method (ignore 
>> the resource issues here, I haven't written my finally block yet):
>>    private void SendTickMessage() {
>>        System.err.println("Tick");
>>              try {
>>            Queue queue = TimerTickUtil.getQueue();
>>            System.err.println(queue.getQueueName());
>>            QueueConnection conn = TimerTickUtil.getQueueConnection();
>>            Session session = 
>> conn.createSession(false,Session.AUTO_ACKNOWLEDGE);
>>            TextMessage msg = session.createTextMessage("TICK");
>>            MessageProducer producer = session.createProducer(queue);
>>            producer.send(msg);
>>        } catch (Exception ex) {
>>            ex.printStackTrace();
>>            try {
>>                InitialContext ctx = new InitialContext();
>>                              NamingEnumeration<NameClassPair> en = 
>> ctx.list("");
>>                while(en.hasMore()) {
>>                    NameClassPair pair =;
>>                    System.err.println(pair.getName() + " -> "+ 
>> pair.getClassName());
>>                }
>>            } catch (Exception ex2) {
>>                ex2.printStackTrace();
>>            }
>>        }
>>    }
>> Now, the problem is that TimerTickUtil.getQueue() is trying to do a 
>> JNDI lookup for the queue, but I have absolutely no idea what form 
>> that JNDI name will take? I ran JConsole to get some idea of the JNDI 
>> namespace, but that was no good, and hence the silly code in the 
>> exception handler that tries to list the entire InitialContext list. 
>> But that's not giving me much to go on either.
>> Can anyone tell me what the JNDI name of my queue will be from the 
>> above information? Is there a sample MDB app in the source tree that 
>> shows how this is done?
>> I'll keep hammering at it and see if I can figure it out.
>> -Neal

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