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The [Dynamic Router|http://www.enterpriseintegrationpatterns.com/DynamicRouter.html] from the [EIP patterns|Enterprise Integration Patterns] allows you to route messages while avoiding the dependency of the router on all possible destinations while maintaining its

 efficiency.

!http://www.enterpriseintegrationpatterns.com/img/DynamicRouter.gif!

In *Camel 2.5* we introduced a {{dynamicRouter}} in the DSL which is like a dynamic [Routing Slip] which evaluates the slip _on-the-fly_.

 

{warning:title=Beware}
You must ensure the expression used for the {{dynamicRouter}} such as a bean, will return {{null}} to indicate the end. Otherwise the {{dynamicRouter}} will keep repeating endlessly.
{warning}


h3. Options

{div:class=confluenceTableSmall}
|| Name || Default Value || Description ||
| {{uriDelimiter}} | {{,}} | Delimiter used if the [Expression] returned multiple endpoints. |
| {{ignoreInvalidEndpoints}} | {{false}} | If an endpoint uri could not be resolved, should it be ignored. Otherwise Camel will thrown an exception stating the endpoint uri is not valid. |
{div}


h3. Dynamic Router in Camel 2.5 onwards

From Camel 2.5 the [Dynamic Router] will set a property (Exchange.SLIP_ENDPOINT) on the [Exchange] which contains the current endpoint as it advanced though the slip. This allows you to know how far we have processed in the slip. (It's a slip because the [Dynamic Router] implementation is based on top of [Routing Slip]).

h4. Java DSL

In Java DSL you can use the {{routingSlip}} as shown below:

You can also use the {{@DynamicRouter}} annotation, for example the Camel 2.4 example below could be written as follows. The {{route}} method would then be invoked repeatedly as the message is processed dynamically. The idea is to return the next endpoint uri where to go. Return {{null}} to indicate the end. You can return multiple endpoints if you like, just as the [Routing Slip], where each endpoint is separated by a delimiter.

{code

:java

}
public class MyDynamicRouter {

    @Consume(uri = "activemq:foo")
    @DynamicRouter
    public String route(@XPath("/customer/id") String customerId, @Header("Location") String location, Document body) {
        // query a database to find the best match of the endpoint based on the input parameteres
        // return the next endpoint uri, where to go. Return null to indicate the end.
    }
}
{code}

h3. Dynamic Router in Camel 2.4 or older

The simplest way to implement this is to use the [RecipientList Annotation] on a Bean method to determine where to route the message.

{code

:java

}
public class MyDynamicRouter {

    @Consume(uri = "activemq:foo")
    @RecipientList
    public List<String> route(@XPath("/customer/id") String customerId, @Header("Location") String location, Document body) {
        // query a database to find the best match of the endpoint based on the input parameteres
        ...
    }
}
{code}

In the above we can use the [Parameter Binding Annotations] to bind different parts of the [Message] to method parameters or use an [Expression] such as using [XPath] or [XQuery].

The method can be invoked in a number of ways as described in the [Bean Integration] such as

* [POJO Producing

]
* [Spring Remoting

]
* [Bean] component

{include:Using This Pattern}