Resequencer

Pattern Catalog

Previous Previous   Next Next

Site HomePatterns HomeTable of Contents

A Message Router can route messages from one channel to different channels based on message content or other criteria. Because individual messages may follow different routes, some messages are likely to pass through the processing steps sooner than others, resulting in the messages getting out of order. However, some subsequent processing steps do require in-sequence processing of messages, for example to maintain referential integrity.

How can we get a stream of related but out-of-sequence messages back into the correct order?

Use a stateful filter, a Resequencer, to collect and re-order messages so that they can be published to the output channel in a specified order.

The Resequencer can receive a stream of messages that may not arrive in order. The Resequencer contains in internal buffer to store out-of-sequence messages until a complete sequence is obtained. The in-sequence messages are then published to the output channel. It is important that the output channel is order-preserving so messages are guaranteed to arrive in order at the next component. Like most other routers, a Resequencer usually does not modify the message contents.

...

Related patterns: Aggregator, Competing Consumers, Message Router, Message Sequence, Pipes and Filters, Splitter, Test Message


Enterprise Integration Patterns Find the full description of this pattern in:
Enterprise Integration Patterns
Gregor Hohpe and Bobby Woolf
ISBN 0321200683
650 pages
Addison-Wesley
Creative Commons License Parts of this page are available under the Creative Commons Attribution license. You can reuse the pattern icon, the pattern name, the problem and solution statements (in bold), and the sketch under this license. Other portions of the text, such as text chapters or the full pattern text, are protected by copyright.

HomePatternsTable of ContentsPrevious Previous   Next Next