How can all of the same subscriber in different instance get the meesages?

Question

Hi
I am using MDB to recieve messages from publisher, used for event and notification, I deploy same MDB into different instance, if there is a event, the publisher will publish a message, and all subscribers in different instance are supposed to get the message, but reffer to the message flow, only one of these MDB will recieve the messages.
One solution is to have different clientID for these MDB in different instances. But unfortunately, the value for clientId should be constant expression.
Here is my code, any suggestion?
@MessageDriven(mappedName = "cluster_publisher_adm", activationConfig = {
     @ActivationConfigProperty(propertyName = "acknowledgeMode", propertyValue = "Auto-acknowledge"),
     @ActivationConfigProperty(propertyName = "subscriptionDurability", propertyValue = "Durable"),
     @ActivationConfigProperty(propertyName = "clientId", propertyValue = "test"),
        @ActivationConfigProperty(propertyName = "subscriptionName", propertyValue = "myTest"),
     @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Topic") })
public class TopicListener implements MessageListener {
    public TopicListener() {
    }How can I have all the MDB in different instances to get the same messages?

Answer 1

I presume you are using Glassfish and Glassfish Message Queue, and that your Glassfish instances are clustered. If so, then if an MDB (listening on a topic) is deployed into the cluster, each message will indeed be delivered to one MDB per cluster rather then to one MDB per instance. This is a feature known as "shared subscriptions".
If you are using Glassfish 2.1.1 or 3 (but not earlier versions) you can disable this using an activation spec property. Take a look at the latest documentation at
http://docs.sun.com/app/docs/doc/821-0027/aeooq?l=en&a=view&q=activationspec
and scroll down to the new property "useSharedSubscriptionInClusteredContainer". You need to set this to false.
Nigel