Optional parameters in EJB QL?

Hello,
I'm trying to create a finder in a container-managed EJB, with optional parameters. What do I mean? Well, I'm looking for certain data in my tables which occur within a certain date interval. I would like to use a single method for this:
findDataInInterval(Integer type, Date occursAfterThisDate, Date occursBeforeThisDate)
Which can conceivably generate at least 4 SQL queries (using a EJB-QL'ish syntax):
select * from my table where type = ?type
select * from my table where type = ?type and mydate > ?occursAfterThisDate
select * from my table where type = ?type and mydate < ?occursBeforeThisDate
select * from my table where type = ?type and mydate > ?occursAfterThisDate and mydate < ?occursBeforeThisDate
Is there a way to generalise the four queries into one entry, so that the mydate clauses are ignored if either (or both) dates are null?
Thanks,
L

Hi Laurent,
Those look like four different custom finders to me.
Regards,