WebSphere Message Brokers
File: aq01155_
Writer: Terry Cowling

Concept topic

This build: July 31, 2007 21:35:08

Subscription points

A subscription point is the name that a subscriber uses to request publications from a particular set of Publication nodes. It is the property of a Publication node that differentiates that Publication node from other Publication nodes in the same message flow.

A subscriber that registers a subscription without specifying a subscription point receives publications from any unnamed Publication node in the message flow, provided that there is a match with the topic and filter specified by the subscriber.

This applies to all message flows running in all brokers connected in the same network, unless the local has been specified when registering the subscription.

Using subscription points

If you have more than one Publication node in a message flow, you can differentiate between them by specifying subscription points. Choose values that indicate the type of message that is routed to each Publication node.

Example

Consider an application that publishes stock prices. The prices that are available from the first Publication node in the message flow are in dollars. This Publication node uses the default subscription point.

You can define a second path through the message flow that takes the price in dollars, and converts this using a defined conversion value, to produce the same message but with the stock price in pounds. These messages are published at a second Publication node that has its subscription point property set to "Pounds".

You might have another message flow, in the same broker or a connected broker, that publishes stock prices in pounds on the same topic. Make sure that it uses the "Pounds" subscription point, and that all other message flows that publish their stock prices in dollars use the default subscription point.

Subscribers specifying the relevant topic (for example, "stock") can then choose whether to receive the information in dollars or in pounds, by using the default subscription point or the "Pounds" subscription point when they subscribe.

Related tasks
Subscribing
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Copyright IBM Corporation 1999, 2007Copyright IBM Corporation 1999, 2007. All Rights Reserved.
This build: July 31, 2007 21:35:08

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