将Spring bean注入Camel DSL

Question

Trying to add Spring bean to Camel body property. Something like:

MVEL: exchange.in.body.limit = uiLimit
<transform>
    <mvel>
        exchange.in.body.limit = uiLimit;
        exchange.in.body;
    </mvel>
</transform>
Spel: request.body.limit = uiLimit

Or even putting in header first:

<setHeader headerName="limit">
  <simple>ref:uiLimit</simple>
</setHeader>

Where uiLimit is:

<bean id="uiLimit" class="java.math.BigInteger">
  <constructor-arg value="${UI_LIMIT} />
</bean>

And still getting null in header and property.

Any ideas why bean lookup in Registry doesn't work for OSGI? (all beans/routes inside single bundle)

PS: this works fine in Route:

<bean ref="uiLimit" method="toString"/>

Answer 1

The transform is only for transforming the message body. Not to mutate headers.

If you want to change a header, use setHeader

Answer 2

The reason of such behaviour is that Exchange created in another bundle and came via exposed service:

<osgi:service ref="someHandler" interface="org.apache.camel.Component"/>

Exchange contains Registry/Context from another bundle where this bean is not declared. All expression languages are working with Registry/Context attached to Exchange and not with Registry of current budle