WebSphere Message Brokers
File: ac12311_
Writer: Catherine Tucker

Task topic

This build: July 31, 2007 21:18:23

Associating fan-out and fan-in aggregation flows

This topic describes how you can associate the fan-out message flow processing with its corresponding fan-in message flow processing by setting the Aggregate Name property of the AggregateControl and AggregateReply nodes in your aggregation flow to the same value.

If you did not configure this property whilst creating your fan-in and fan-out flows you must complete this task.

Before you start:

You must have completed the following tasks:

The Aggregate Name must be contextually unique within a broker. You can have only one AggregateControl node and one AggregateReply node with a particular Aggregate Name, although it is possible to have more than one AggregateControl node with the same Aggregate Name, as described in Using multiple AggregateControl nodes. It is not advisable to deploy a fan-in flow to multiple execution groups on the same broker.

You can either create the fan-out and fan-in flows in the same message flow, or in two different message flows. In either case, the two parts of the aggregation are associated by setting the Aggregate Name property.

The way in which you configure your aggregation flow depends on a number of factors:

A single flow is easier to implement for a simple case, but there are some limitations to this approach, and, in most cases, you will find that the flexibility offered by two message flows is preferable. The following sample shows the use of two flows for aggregation: You can view samples only when you use the information center that is integrated with the Message Brokers Toolkit.

The advantages of creating separate fan-out and fan-in flows are:

To associate the fan-out flow with the fan-in flow:

  1. Open the message flow containing your fan-out flow.
  2. Right-click the AggregateControl node and click Properties.
  3. Set the Aggregate Name property of the AggregateReply node to identify this aggregation. The Aggregate Name that you specify must be contextually unique within a broker.
  4. If you have separate fan-out and fan-in flows:
    1. Press Ctrl-S to save the fan-out message flow and validate its configuration.
    2. Open the message flow containing your fan-in flow.
  5. Right-click the AggregateReply node and click Properties.
  6. Set the Aggregate Name property of the AggregateReply node to the same value that you set for the Aggregate Name property in the corresponding AggregateControl node in the fan-out flow.
  7. Press Ctrl-S to save the message flow and validate its configuration.
In Version 5.0 of the product, fan-out and fan-in flows were also associated by sending control messages from the AggregateControl node to the AggregateReply node. This facility is no longer available. For optimum performance it is preferable not to connect the AggregateControl and AggregateReply node. However, if you do want to use control messages in your aggregations and you want to connect these two nodes refer to Using control messages in aggregation flows.
Note: Connections between the AggregateControl and AggregateReply node created in Version 5.0 will be ignored once you have migrated them to version 6.0 unless you set the broker environment to specify otherwise. For more information see, Using control messages in aggregation flows.
Related concepts
Message flows overview
Message flow aggregation
Related tasks
Configuring aggregation flows
Creating the aggregation fan-out flow
Setting timeouts for aggregation
Using multiple AggregateControl nodes
Handling exceptions in aggregation flows
Using control messages in aggregation flows
Related reference
AggregateControl node
AggregateReply node
AggregateRequest node
Notices | Trademarks | Downloads | Library | Support | Feedback

Copyright IBM Corporation 1999, 2007Copyright IBM Corporation 1999, 2007. All Rights Reserved.
This build: July 31, 2007 21:18:23

ac12311_ This topic's URL is: