A message router, shown in Figure 4.7, 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.
A message router can easily be implemented in Fuse Mediation Router 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).
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:
from("seda:a").choice() .when(header("foo").isEqualTo("bar")).to("seda:b") .when(header("foo").isEqualTo("cheese")).to("seda:c") .otherwise().to("seda:d");
The following example shows how to configure the same route in XML:
<camelContext id="buildSimpleRouteWithChoice" xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="seda:a"/> <choice> <when> <xpath>$foo = 'bar'</xpath> <to uri="seda:b"/> </when> <when> <xpath>$foo = 'cheese'</xpath> <to uri="seda:c"/> </when> <otherwise> <to uri="seda:d"/> </otherwise> </choice> </route> </camelContext>