ServiceMix Bean

The ServiceMix Bean component provides integration with beans (POJOs) with the JBI bus to make it easy to use POJOs to process JBI message exchanges.

Deployment

Currently (v 3.1), servicemix-bean supports two different deployment models. The first one uses an xbean.xml configuration file where one can configure the different endpoints / beans that will be used. The other one only works with a static configuration file (servicemix.xml) and can not be used with standard JBI packaging but allows automatic detection of the beans to expose.

`xbean.xml`

<beans xmlns:bean="http://servicemix.apache.org/bean/1.0">

  <bean:endpoint service="test:service" endpoint="endpoint" bean="#listenerBean"/>

  <bean id="listenerBean" class="org.apache.servicemix.bean.beans.ListenerBean"/>

</beans>

Static configuration

When used in a static configuration, beans can be automatically discovered amongst spring configured beans:

<beans xmlns:sm="http://servicemix.apache.org/config/1.0"
       xmlns:bean="http://servicemix.apache.org/bean/1.0"
       xmlns:test="urn:test">

  <sm:container id="jbi" embedded="true" createMBeanServer="false">
    <sm:activationSpecs>
      <sm:activationSpec>
        <sm:component>
          <bean:component/>
        </sm:component>
      </sm:activationSpec>
    </sm:activationSpecs>
  </sm:container>

  <bean id="consumerBean" class="org.apache.servicemix.bean.beans.ConsumerBean"/>
  <bean id="listenerBean" class="org.apache.servicemix.bean.beans.ListenerBean"/>
  <bean id="annotatedBean" class="org.apache.servicemix.bean.beans.AnnotatedBean"/>
  <bean id="plainBean" class="org.apache.servicemix.bean.beans.PlainBean"/>

</beans>

Such beans can be accessed by resolving a URI:

DocumentFragment epr = URIResolver.createWSAEPR("bean:annotatedBean");
ServiceEndpoint se = client.getContext().resolveEndpointReference(epr);
exchange.setEndpoint(se);

Beans can also be discovered by searching within defined packages:

<beans xmlns:sm="http://servicemix.apache.org/config/1.0"
       xmlns:bean="http://servicemix.apache.org/bean/1.0"
       xmlns:test="urn:test">

  <sm:container id="jbi" embedded="true" createMBeanServer="false">
    <sm:activationSpecs>
      <sm:activationSpec>
        <sm:component>
          <bean:component searchPackages="org.apache.servicemix.bean.beans"/>
        </sm:component>
      </sm:activationSpec>
    </sm:activationSpecs>
  </sm:container>

</beans>

In such a case, beans must have the @Endpoint annotation.

Of course, you can use the endpoint xml element to configure your POJOs:

<beans xmlns:sm="http://servicemix.apache.org/config/1.0"
       xmlns:bean="http://servicemix.apache.org/bean/1.0"
       xmlns:test="urn:test">

  <sm:container id="jbi" embedded="true" createMBeanServer="false">
    <sm:activationSpecs>
      <sm:activationSpec>
        <sm:component>
          <bean:component>
            <bean:endpoints>
              <bean:endpoint service="test:service" endpoint="endpoint" bean="#listenerBean">
            </bean:endpoints>
          <bean:component>
        </sm:component>
      </sm:activationSpec>
    </sm:activationSpecs>
  </sm:container>

  <bean id="listenerBean" class="org.apache.servicemix.bean.beans.ListenerBean"/>

</beans>

MessageExchange dispatching

If the POJO deployed implements the org.apache.servicemix.MessageExchangeListener, every message received for this POJO will be dispatched to the onMessageExchange method.

In other cases, exchanges in a provider role will be dispatched according to the MethodInvocationStrategy configured on the endpoint. The default one try to find the method according to the operation name defined on the exchange. If there is only a single method acting as an operation, it will always be used.

Annotations

The servicemix-bean component can accept different kind of POJOs. These POJOs may be annotated to customize their behavior. All the following annotations belong to the org.apache.servicemix.bean package.

Annotation	Target	Description
Callback	Method
Content	Parameter
Correlation	Type
Endpoint	Type	This annotation is mandatory if the bean is automatically searched from a list of packages.
ExchangeTarget	Field
Operation	Method
Property	Parameter
XPath	Parameter

In addition, standard annotations can be used:

Annotation	Target	Description
Resource	Field	The Resource annotation marks a resource that is needed by the application. Currently, this annotation is only supported on fields of type `ComponentContext` and `DeliveryChannel`. The component will inject the specified resource when the POJO is instanciated.
PostConstruct	Method	The PostConstruct annotation is used on a method that needs to be executed after dependency injection is done to perform any initialization.
PreDestroy	Method	The PreDestroy annotation is used on methods as a callback notification to signal that the instance is in the process of being removed by the container.

The following interfaces are part of this API:

Interface	Description
MessageExchagneListener	When the POJO implements this interface, all exchanges will be dispatched to the `onMessageExchange` method.
Destination	This interface can be used to define a property on the bean, annotated with the `@ExchangeTarget` annotation. This is a very simple API to send exchanges from a POJO. More complex use cases can use an injected `DeliveryChannel` directly or to create a ServiceMix client.

Examples

URI

You can use a handy URI to refer to beans using the Spring names of beans.

bean:someName

The above would refer to the bean named someName in the Spring ApplicationContext which is used to boot up the bean component.

Child pages

servicemix-bean