Chapter 133. Ref
Ref Component
The ref: component is used for lookup of existing endpoints bound in the Registry.
URI format
ref:someName
Where someName is the name of an endpoint in the Registry (usually, but not always, the Spring registry). If you are using the Spring registry,
someName would be the bean ID of an endpoint in the Spring registry.
Runtime lookup
This component can be used when you need dynamic discovery of endpoints in the Registry where you can compute the URI at runtime. Then you can look up the endpoint using the following code:
// lookup the endpoint
String myEndpointRef = "bigspenderOrder";
Endpoint endpoint = context.getEndpoint("ref:" + myEndpointRef);
Producer producer = endpoint.createProducer();
Exchange exchange = producer.createExchange();
exchange.getIn().setBody(payloadToSend);
// send the exchange
producer.process(exchange);
...
And you could have a list of endpoints defined in the Registry such as:
<camelContext id="camel" xmlns="http://activemq.apache.org/camel/schema/spring">
<endpoint id="normalOrder" uri="activemq:order.slow"/>
<endpoint id="bigspenderOrder" uri="activemq:order.high"/>
...
</camelContext>Sample
In the sample below we use the
ref: in the URI to reference the endpoint with the spring ID, endpoint2:
<bean id="mybean" class="org.apache.camel.spring.example.DummyBean">
<property name="endpoint" ref="endpoint1"/>
</bean>
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
<jmxAgent id="agent" disabled="true"/>
<endpoint id="endpoint1" uri="direct:start"/>
<endpoint id="endpoint2" uri="mock:end"/>
<route>
<from ref="endpoint1"/>
<to uri="ref:endpoint2"/>
</route>
</camelContext>
You could, of course, have used the
ref attribute instead:
<to ref="endpoint2"/>
Which is the more common way to write it.
