xpfStringToAggregateId

The function will only return an aggregateId when the actual returned aggrId is an existing aggregate in the actual data base. 
When the actual aggregateId is not a valid id, the function will fail, return the value xpxNULLID and throw an exception.

FUNCTION xpfStringToAggregateId (stringValue : STRING)
                                 aggregateId : AGGREGATE OF GENERIC;