WebSphere Message Brokers
File: au19720_
Writer: Jane Brockbank

Reference topic

This build: July 31, 2007 21:39:54

Subscriptions and topics

Events are published to provide notification of changes to the subscription tables, changes in the list of defined topics or their access control lists.

Registration or de-registration of subscriptions causes events to be published using the following system topics:
$SYS/Broker/broker_name/Subscription/topic
where:
broker_name
is the name of the broker issuing this message
topic
is the original topic on which the subscription is being, or was, registered

The body of each publication is an XML message giving additional information concerning the registration or de-registration request.

These events are nonpersistent, non-retained publications.

Examples

Here are example event messages for a subscription being created, changed, and deleted.

Subscription created

Event publication topic = "$SYS/Broker/Broker1/Subscription/stock/IBM"

<Broker uuid="1234" label="Broker1" version="1">
  <ControlGroup>
    <DynamicSubscriptionEngine>
      <Topic name="stock/IBM">
        <Create>
          <Subscription
            clientId="mqrfh2:Broker1:client1queue"
            subscriptionPoint="poundsSterling"
            filter="currentPrice>100"
            user="Fred"
            persistent="true"
            localOnly="false"
            pubOnReqOnly="false"
            informIfRet="true"
            expiryTimeStamp="2000-12-31 23:59:59"
            createTimeStamp="2000-01-01 00:00:00"
            tempDynamicQueue="false"
            clientContext="hex digits"/>
        </Create>
      </Topic>
    </DynamicSubscriptionEngine>
  </ControlGroup>
</Broker>

Subscription changed

Event publication topic = "$SYS/Broker/Broker1/Subscription/stock/IBM"

<Broker uuid="1234" label="Broker1" version="1">
  <ControlGroup>
    <DynamicSubscriptionEngine>
      <Topic name="stock/IBM">
        <Change>
          <Subscription
            clientId="mqrfh2:Broker1:client1queue"
            subscriptionPoint="poundsSterling"
            filter="currentPrice>100"
            user="Fred"
            persistent="false"
            localOnly="true"
            pubOnReqOnly="true"
            informIfRet="false"
            expiryTimeStamp="2005-12-31 23:59:59"
            createTimeStamp="2000-01-01 00:00:00"
            tempDynamicQueue="false"
            clientContext="hex digits"/>
        </Change>
      </Topic>
    </DynamicSubscriptionEngine>
  </ControlGroup>
</Broker>

Subscription deleted (deregistered)

Event publication topic = "$SYS/Broker/Broker1/Subscription/stock/IBM"

<Broker uuid="1234" label="Broker1" version="1">
  <ControlGroup>
    <DynamicSubscriptionEngine>
      <Topic name="stock/IBM">
        <Delete>
          <Subscription
            clientId="mqrfh2:Broker1:client1queue"
            subscriptionPoint="poundsSterling"
            filter="currentPrice>100"
            user="Fred"/>
        </Delete>
      </Topic>
    </DynamicSubscriptionEngine>
  </ControlGroup>
</Broker>
Related concepts
Broker domains
Related tasks
Creating a broker
Notices | Trademarks | Downloads | Library | Support | Feedback

Copyright IBM Corporation 1999, 2007Copyright IBM Corporation 1999, 2007. All Rights Reserved.
This build: July 31, 2007 21:39:54

au19720_ This topic's URL is: