event:inbound-channel-adapter with payload-expression not able to resolve bean - events

Question

I'm attempting to use the event:inbound-channel-adapter as an ApplicationEventListener to capture the ContextRefreshedEvent so I can dynamically start a file:inbound-channel-adapter like:
<file:inbound-channel-adapter id="filesIn" auto-startup="false"
directory="${input.location}" channel="fileInChannel">
<integration:poller ref="filesInPoller" />
</file:inbound-channel-adapter>
<event:inbound-channel-adapter id='appStarter' channel="nullChannel"
error-channel="errorChannel"
event-types="org.springframework.context.event.ContextRefreshedEvent"
payload-expression="#filesIn.start()"/>
But I get the following error indicating the sPel payload-expression cannot find the filesIn bean:
Exception in thread "main" org.springframework.expression.spel.SpelEvaluationException: EL1057E:(pos 1): No bean resolver registered in the context to resolve access to bean 'filesIn'
at org.springframework.expression.spel.ast.BeanReference.getValueInternal(BeanReference.java:45)
at org.springframework.expression.spel.ast.CompoundExpression.getValueRef(CompoundExpression.java:49)
at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:82)
at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:93)
at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:72)
at org.springframework.integration.event.inbound.ApplicationEventListeningMessageProducer.sendEventAsMessage(ApplicationEventListeningMessageProducer.java:113)
at org.springframework.integration.event.inbound.ApplicationEventListeningMessageProducer.onApplicationEvent(ApplicationEventListeningMessageProducer.java:91)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:96)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:334)
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:948)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
Am I correct in believing that the file:inbound-channel-adapter is able to be started in this way?
Thanks

Answer 1

What version of Spring Integration are you using? The ability to reference a bean #filesIn was added to this adapter in 3.0.
If you are using 2.2 or below, upgrade to the current release (or at least 3.0.4).
In any case, you can't just send that command to nullChannel, it will evaluate to null and you can't have a null payload; you'll have to send '#filesIn.start()' to a <control-bus/>.
EDIT:
Or, "#filesIn.start() == null ? 'foo' : 'bar'" will send foo to the nullChannel.