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The Content Enricher helps us in situations where a message receiver requires more - or different - data elements than the message creator provides. There are surprisingly many situations where the opposite effect is desired: removing data elements from a message.

How do you simplify dealing with a large message, when you are interested only in a few data items?

Use a Content Filter to remove unimportant data items from a message leaving only important items.

The Content Filter does not necessarily just remove data elements. A Content Filter is also useful to simplify the structure of the message. Often times, messages are represented as tree structures. Many messages originating from external systems or packaged applications contain many levels of nested, repeating groups because they are modeled after generic, normalized database structures. Frequently, known constraints and assumptions make this level of nesting superfluous and a Content Filter can be used to 'flatten' the hierarchy into a simple list of elements than can be more easily understood and processed by other systems.

Related patterns: Content Enricher

Find the full description of this pattern in: Enterprise Integration Patterns Gregor Hohpe and Bobby Woolf ISBN 0321200683 650 pages Addison-Wesley

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