servicemix-bean

 ServiceMix Bean组件提供了JBI总线与bean(POJO)的集成，这使得易于使用POJO来处理JBI消息交换。类似于在J2EE中的消息驱动Bean，一个POJO将从NMR接收消息，并可以以任何方式处理消息。不像JMS组件中的编码已经完成了，Bean组件给予了开发者可以创建任何类型的消息的自由，但是这必须是要手动编码的。

POJOs

有若干种POJO可用来部署到servicemix-bean。

MessageExchangeListener

这是第一种可部署的POJO类型，它实现了MessageExchangeListener接口。在这种情况下，servicemix-bean作为轻量级容器组件的替代物。这个层次提供了对接收到的和发送的交换的绝大部分控制。通常会使用注入的DeliveryChannel来回送交换。

这些POJO是低层次的POJO。你需要理解JBI API和消息交换模式以求能正确处理进入的交换。

Trace example

import org.apache.servicemix.MessageExchangeListener;

import javax.annotation.Resource;
import javax.jbi.messaging.DeliveryChannel;
import javax.jbi.messaging.ExchangeStatus;
import javax.jbi.messaging.MessageExchange;
import javax.jbi.messaging.MessagingException;

public class ListenerBean implements MessageExchangeListener {

    @Resource
    private DeliveryChannel channel;

    public void onMessageExchange(MessageExchange exchange) throws MessagingException {
        System.out.println("Received exchange: " + exchange);
        exchange.setStatus(ExchangeStatus.DONE);
        channel.send(exchange);
    }
}

Message processing example

import org.apache.servicemix.MessageExchangeListener;
import org.apache.servicemix.jbi.util.MessageUtil;
import org.apache.servicemix.jbi.jaxp.SourceTransformer;

import javax.annotation.Resource;
import javax.jbi.messaging.DeliveryChannel;
import javax.jbi.messaging.ExchangeStatus;
import javax.jbi.messaging.MessageExchange;
import javax.jbi.messaging.MessagingException;
import javax.jbi.messaging.NormalizedMessage;
import javax.xml.transform.Source;

public class ListenerBean implements MessageExchangeListener {

    @Resource
    private DeliveryChannel channel;

    public void onMessageExchange(MessageExchange exchange) throws MessagingException {
        if (exchange.getStatus() == ExchangeStatus.ACTIVE) {
                        NormalizedMessage message = exchange.getMessage("in");
          Source content = message.getContent();
   //process content according to your logic
   //e.g. to access the message body as a String use
   String body = (new SourceTransformer()).toString(content);

   message.setContent(content);
   exchange.setMessage(message, "out");
   channel.send(exchange);
        }
    }

}

部署

目前版本(v 3.1)的servicemix-bean支持两种不同的部署模型。第一种是使用xbean.xml配置文件。另一种是与静态配置文件servicemix.xml一起作用，但不能与标准JBI封装一起使用。

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

<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>

这些bean可以通过解析一个URI获取

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

Bean也可以通过搜索一个定义的包被发现

<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>

在这种情况下，bean必须要有@Endpoint注释。

当然，也可以使用endpoint xml元素来配置POJO。

<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>