Chapter 260. Ref Component

Available as of Camel version 1.2

The ref: component is used for lookup of existing endpoints bound in the Registry.

260.1. URI format

ref:someName[?options]

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.

260.2. Ref Options

The Ref component has no options.

The Ref endpoint is configured using URI syntax:

ref:name

with the following path and query parameters:

260.2.1. Path Parameters (1 parameters):

NameDescriptionDefaultType

name

Required Name of endpoint to lookup in the registry.

 

String

260.2.2. Query Parameters (4 parameters):

NameDescriptionDefaultType

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN/ERROR level and ignored.

false

boolean

exceptionHandler (consumer)

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this options is not in use. By default the consumer will deal with exceptions, that will be logged at WARN/ERROR level and ignored.

 

ExceptionHandler

exchangePattern (consumer)

Sets the default exchange pattern when creating an exchange.

 

ExchangePattern

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

260.3. 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>

260.4. Sample

In the sample below we use the ref: in the URI to reference the endpoint with the spring ID, endpoint2:

You could, of course, have used the ref attribute instead:

<to ref="endpoint2"/>

Which is the more common way to write it.