Error with transform

Hi all,

We have a SIMPLE transform step in a route that reports an exception
infrequently. I suspect the exception arises when a data element is missing,
which could be the case infrequently. When missing, I want the transform to
just use empty space and not report exception.

Here is the transform:

<transform>
<simple>JMS Channel processing tweet event from
@${header.Status$User$ScreenName} at ${header.$Event$Start}</simple>
</transform>

Here is the exception:
[Camel (STEP3_EDATweetReceivedFromJMS) thread #10 -
JmsConsumer[Event::WebM::Communication::Twitter::1.1::TweetReceived]]
EndpointMessageListener WARN Execution of JMS message
listener failed. Caused by: [org.apache.camel.RuntimeCamelException -
java.lang.ArrayIndexOutOfBoundsException]
org.apache.camel.RuntimeCamelException:
java.lang.ArrayIndexOutOfBoundsException
at
org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException(ObjectHelper.java:1363)
at
org.apache.camel.component.jms.EndpointMessageListener$EndpointMessageListenerAsyncCallback.done(EndpointMessageListener.java:186)
at
org.apache.camel.component.jms.EndpointMessageListener.onMessage(EndpointMessageListener.java:107)
at
org.springframework.jms.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:562)
at
org.springframework.jms.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:500)
at
org.springframework.jms.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:468)
at
org.springframework.jms.listener.AbstractPollingMessageListenerContainer.doReceiveAndExecute(AbstractPollingMessageListenerContainer.java:325)
at
org.springframework.jms.listener.AbstractPollingMessageListenerContainer.receiveAndExecute(AbstractPollingMessageListenerContainer.java:263)
at
org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener(DefaultMessageListenerContainer.java:1096)
at
org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.executeOngoingLoop(DefaultMessageListenerContainer.java:1088)
at
org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.run(DefaultMessageListenerContainer.java:985)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ArrayIndexOutOfBoundsException

How do I write this so that no exceptions are thrown when the data element
is missing?

Thanks!
Michael