MessageProcessor implementation that logs the current element of a value evaluated from it using
an expression evaluator. By default the current messages is logged using the Level.DEBUG
level to the 'org.mule.api.processor.LoggerMessageProcessor' category. The level and
category can both be configured to suit your needs.
Method used to perform any initialisation work. If a fatal error occurs during
initialisation an InitialisationException should be thrown,
causing the Mule instance to shutdown. If the error is recoverable, say by
retrying to connect, a RecoverableException should be thrown.
There is no guarantee that by throwing a Recoverable exception that the Mule
instance will not shut down.