What is the correct failure behavior for org.apache.directory.server.core.partition.lookup()

[Icky Dude]

Hi,

Interface documentation isn't completel clear about what an
implementor of the partition interface should do when the object
specified by the LookupOperationContext does not exist in a call to
lookup().

Should null be returned or should an NamingException be thrown, if so,
which NamingException.

Thanks.