Commitment Control

Looking for some advice.  We have an application that uses a table entry
to get the next available number for an ID field used in a series of
tables.  This number is used in both an RPG and a Java program, and we
are concerned about ensuring that the same number is never issued twice.
My thought was to write a user defined SQL function that would increment
the table value and return the next number, using commitment control to
ensure that the row was locked for the entire process.  We got the
function created, then figured out that we needed to journal the table
in order to use commitment control.  We are not journalling anything on
the box today for performance and data storage reasons and at this point
would prefer to avoid it.  
 
Is commitment control overkill in this case?  We are using an update
cursor to perform the operation, so will that keep the record locked for
the duration of the function execution?  If not, is there another way to
do this gracefully without commitment control and journalling?
 
Thanks in advance,
 
Jim Reinardy
Badger Meter, Inc.
Milwaukee, WI