Chapter 274. Ref Component
Available as of Camel version 1.2
The ref: component is used for lookup of existing endpoints bound in the Registry.
274.1. 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.
274.2. 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:
274.2.1. Path Parameters (1 parameters):
Name | Description | Default | Type |
---|---|---|---|
name | Required Name of endpoint to lookup in the registry. | String |
274.2.2. Query Parameters (4 parameters):
Name | Description | Default | Type |
---|---|---|---|
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 |
274.3. 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>
274.4. 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.