docs/user-manual/modules/ROOT/pages/choice-eip.adoc

[[choice-eip]]
= Choice EIP
:page-source: core/camel-core-engine/src/main/docs/eips/choice-eip.adoc

The
http://www.enterpriseintegrationpatterns.com/ContentBasedRouter.html[Content
Based Router] from the xref:enterprise-integration-patterns.adoc[EIP
patterns] allows you to route messages to the correct destination based
on the contents of the message exchanges.

image::eip/ContentBasedRouter.gif[image]

== Choice options

// eip options: START
The Choice EIP supports 2 options which are listed below:

[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *whenClauses* | Sets the when clauses |  | List
| *otherwise* | Sets the otherwise node |  | OtherwiseDefinition
|===
// eip options: END

== Examples

The following example shows how to route a request from an input
*seda:a* endpoint to either *seda:b*, *seda:c* or *seda:d* depending on
the evaluation of various xref:predicate.adoc[Predicate] expressions

[source,java]
----
RouteBuilder builder = new RouteBuilder() {
    public void configure() {
        from("direct:a")
            .choice()
                .when(simple("${header.foo} == 'bar'"))
                    .to("direct:b")
                .when(simple("${header.foo} == 'cheese'"))
                    .to("direct:c")
                .otherwise()
                    .to("direct:d");
    }
};
----

TIP: See xref:faq/why-can-i-not-use-when-or-otherwise-in-a-java-camel-route.adoc[Why
can I not use when or otherwise in a Java Camel route] if you have
problems with the Java DSL, accepting using `when` or `otherwise`.

And the same example using XML:

[source,xml]
----
<camelContext xmlns="http://camel.apache.org/schema/spring">
    <route>
        <from uri="direct:a"/>
        <choice>
            <when>
                <simple>${header.foo} == 'bar'</simple>
                <to uri="direct:b"/>
            </when>
            <when>
                <simple>${header.foo} == 'cheese'</simple>
                <to uri="direct:c"/>
            </when>
            <otherwise>
                <to uri="direct:d"/>
            </otherwise>
        </choice>
    </route>
</camelContext>
----