@RoutingSlip Annotation
As of Camel 2.4.0 we now support the use of @RoutingSlip on a bean method to easily create a dynamic Routing Slip using a Java method.
Simple Example using @Consume and @RoutingSlip
package com.acme.foo; public class RouterBean { @Consume(uri = "activemq:foo") @RoutingSlip public String[] route(String body) { return new String[]{"activemq:bar", "activemq:whatnot"}; } }
For example if the above bean is configured in Spring when using a <camelContext> element as follows
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://activemq.apache.org/camel/schema/spring http://activemq.apache.org/camel/schema/spring/camel-spring.xsd "> <camelContext xmlns="http://activemq.apache.org/camel/schema/spring"/> <bean id="myRecipientList" class="com.acme.foo.RouterBean"/> </beans>
then a route will be created consuming from the foo queue on the ActiveMQ component which when a message is received the message will be forwarded to the endpoints defined by the result of this method call - namely the bar and whatnot queues.
How it works
The return value of the @RoutingSlip method is converted to either a java.util.Collection / java.util.Iterator or array of objects where each element is converted to an Endpoint or a String, or if you are only going to route to a single endpoint then just return either an Endpoint object or an object that can be converted to a String. So the following methods are all valid
@RoutingSlip public String[] route(String body) { ... } @RoutingSlip public List<String> route(String body) { ... } @RoutingSlip public Endpoint route(String body) { ... } @RoutingSlip public Endpoint[] route(String body) { ... } @RoutingSlip public Collection<Endpoint> route(String body) { ... } @RoutingSlip public URI route(String body) { ... } @RecipientList public URI[] route(String body) { ... }
Then for each endpoint or URI the message is forwarded a separate copy to that endpoint.
You can then use whatever Java code you wish to figure out what endpoints to route to; for example you can use the Bean Binding annotations to inject parts of the message body or headers or use Expression values on the message.
More Complex Example Using DSL
In this example we will use more complex Bean Binding, plus we will use a separate route to invoke the Recipient List
public class RouterBean2 { @RoutingSlip public String route(@Header("customerID") String custID String body) { if (custID == null) return null; return "activemq:Customers.Orders." + custID; } } public class MyRouteBuilder extends RouteBuilder { protected void configure() { from("activemq:Orders.Incoming").routingSlip(bean("myRouterBean", "route")); } }
Notice how we are injecting some headers or expressions and using them to determine the recipients using Routing Slip EIP.
See the Bean Integration for more details.