Re: what's the problem with bean expression

[Willem Jiang <wi...@gmail.com>]

Please use the users@camel.apache.org to ask this kind of question.

My comments are in the mail.

On 7/23/64 4:29 AM, wow wrote:
> I use camel 2.8.0 with servicemix4.3. I set up a dynamic router by camel-context.xml. as follows:
> <?xml version="1.0" encoding="UTF-8"?>
> <beans xmlns="http://www.springframework.org/schema/beans"
>         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>         xsi:schemaLocation="
>         http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
>         http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd">
>
>      <classpath>
>          <library>osgi:org.apache.camel.camel-spring</library>
>          <library>osgi:com.hongbo.cobweb.utils</library>
>          <library>osgi:com.hongbo.cobweb.store.api</library>
>          <library>osgi:com.hongbo.cobweb.store.entity</library>
>          <library>osgi:com.hongbo.cobweb.nmr.api</library>
>          <library>osgi:com.hongbo.cobweb.resource.manager</library>
>          <library>osgi:com.mongodb</library>
>      </classpath>
>
>      <bean id="bizTypeDR" class="com.hongbo.cobweb.master.router.BizTypeDynamicRouter" init-method="init">
>          <property name="gatewayUri" value="jbi:service:http://cobweb.hongbo.net.cn/default/master/gateway" />
>          <property name="storeUri" value="jbi:service:http://cobweb.hongbo.net.cn/default/master/store" />
>          <property name="storeFactoryName" value="MongoMessageStore" />
>      </bean>
>
>      <camelContext id="camelContext" xmlns="http://camel.apache.org/schema/spring">
>          <route>
>              <from uri="jbi:service:http://cobweb.hongbo.net.cn/default/master/camel?mep=in-out" />
>              <dynamicRouter>
>                  <method ref="bizTypeDR" method="route"/>
>              </dynamicRouter>
>          </route>
>      </camelContext>
> </beans>
>
> bizTypeDR bean:
>      @DynamicRouter(ignoreInvalidEndpoints=true)
>      public String route(@Header(MessageHeader.CW_MSG_BIZ_TYPE) String bizType, Exchange exchange) {
>          // query a database to find the best match of the endpoint based on the input parameteres
>          // return the next endpoint uri, where to go. Return null to indicate the end.
>          if (started.get()) {
>              if (exchange.hasOut()) {
>                  return null;
>              }
>              if (types != null&&  types.size()>  0&&  bizType != null) {
>                  WrapperMessageBizType mbt = types.get(bizType);
>                  if (mbt != null&&  mbt.getSaIds() != null&&  mbt.getSaIds().size()>  0) {
>                      exchange.getIn().setHeader(MessageHeader.CW_INNER_MSG_BIZ_URI, mbt.getUri());
>                      return gatewayUri;
>                  }
>              }
>          }
>          return storeUri;
>      }
>
> It finish selecting one approach(gatewayUri or storeUri)
>
> But I debug the camel-su. When (gatewayUri or storeUri) downflow components return an exchange with out message(it contains body and headers), camel ignore headers and think the body is next uri in BeanExpress. Is it a bug?? Camel should return the exchange to upflow component(http) in servicemix.
>
> BeanExpress code:
> org.apache.camel.language.bean.BeanExpression
> line 161-163
>                  resultExchange.setPattern(ExchangePattern.InOut);
>                  processor.process(resultExchange);
>                  result = resultExchange.getOut().getBody();
> In line 163, resultExchange is ok. It contains In Message and Out Message returned by downflow components in servicemix. The out Message has headers and body. but 163, camel bean expression only cares about the body of out message and ignore headers of out message.
>
BeanExpression doesn't take care of the message header as the result is 
set the to the out message body.

If you just want to change the endpoint uri dynamically, you can try to 
use the recipient list[1]
[1]http://camel.apache.org/recipient-list.html

> How can I use dynamic router in camel. It can return entirely exchange from downflow components to upflow component.
>
>                                                     thank you very much!
>
>
>


-- 
Willem
----------------------------------
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