Configuring Camel

How do I add a component?

You might first want to read Writing Components for a background in how to implement a new component. Typically it means you write an implementation of the Component interface, usually deriving from DefaultComponent.

You can then register your component explicitly via:

CamelContext context = new DefaultCamelContext();
context.addComponent("foo", new FooComponent(context));

However you can use the auto-discovery feature of Camel where by Camel will automatically add a Component when an endpoint URI is used. To do this you would create a file called:

/META-INF/services/org/apache/camel/component/foo

with contents:

class=org.acme.FooComponent

(You can add other property configurations in there too if you like.)

Then if you refer to an endpoint as foo://somethingOrOther Camel will auto-discover your component and register it.

The FooComponent can then be auto-injected with resources using the Injector, such as to support Spring based auto-wiring, or to support @Resource (EJB3 style) injection or Guice style @Inject injection.

Working with Spring XML

You can configure a component via Spring using the following mechanism:

  <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
      <jmxAgent id="agent" disabled="true"/>
  </camelContext>

  <bean id="activemq" class="org.apache.camel.component.jms.JmsComponent">
    <property name="connectionFactory">
      <bean class="org.apache.activemq.ActiveMQConnectionFactory">
        <property name="brokerURL" value="vm://localhost?broker.persistent=false&amp;broker.useJmx=false"/>
      </bean>
    </property>
  </bean>

Which allows you to configure a component using some name (activemq in the above example), then you can refer to the component using activemq:[queue:|topic:]destinationName.

If you want to add explicit Spring 2.x XML objects to your XML then you could use the xbean-spring which tries to automate most of the XML binding work for you; or you could look in camel-spring at CamelNamespaceHandler you’ll see how we handle the Spring XML stuff (warning it’s kinda hairy code to look at :smile:). If you wanted <fooComponent> to be a standard part of the core Camel schema then you’d hack that file to add your component & contribute a patch to the camel XSD. Otherwise you could write your own namespace & schema if you prefer.

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