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Message Router


A message router, shown in Figure 13, is a type of filter that consumes messages from a single consumer endpoint and redirects them to the appropriate target endpoint, based on a particular decision criterion. A message router is concerned only with redirecting messages; it does not modify the message content.

Figure 13. Message Router Pattern

Message router pattern

A message router can easily be implemented in Apache Camel using the choice() processor, where each of the alternative target endpoints can be selected using a when() subclause (for details of the choice processor, see Processors).

Java DSL example

The following Java DSL example shows how to route messages to three alternative destinations (either seda:a, seda:b, or seda:c) depending on the contents of the foo header:


XML configuration example

The following example shows how to configure the same route in XML:

<camelContext id="buildSimpleRouteWithChoice" xmlns="">
    <from uri="seda:a"/>
        <xpath>$foo = 'bar'</xpath>
        <to uri="seda:b"/>
        <xpath>$foo = 'cheese'</xpath>
        <to uri="seda:c"/>
        <to uri="seda:d"/>

Choice without otherwise

If you use choice() without an otherwise() clause, any unmatched exchanges are dropped by default.

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