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Re: SUBCLASSING, again

Hi All!

I think Entries and Object Classes are being confused in this discussion.
Nowhere does X.501 say that the superclasses of a Structural Object Class
cannot be Auxiliary.  In fact, there is no explicit statement that any of
the superclasses must be Structural.

For ENTRIES however, it is clear that there is exactly one Structural
Object Class.  Any additions or deletions of attributes or additions of
(Auxiliary) Object Classes to an ENTRY must be handled by a Content Rule.
There is nothing in the specification of a Content Rule that prohibits the
use of an Auxiliary Object Class.

For many years, I have been told by implementors that the products do not
support Content Rules!  Given this fact, if Auxiliary Object Classes could
not be superclasses, no Auxiliary Object Classes could never be used.
X.509 clearly intends that Auxiliary Object Classes be used, as it defines
several.

I think this sentence in the Models draft must be removed from section
2.4.2:
      "Structural object classes cannot subclass auxiliary object classes."

I think section 2.4.2 should be clarified to indicate that multiple
inheritance is possible, as is clearly stated in X.501, clause 8.3:
        "An object class may be derived from two or more direct
superclasses (superclasses not part of the same
         superclass chain). This feature of subclassing is termed multiple
inheritance."

 Perhaps this paragraph could be added to the end of section 2.4.2:
        "A Structural Object Class that is formed by multiple inheritance
has one direct superclass which is a
         structural object class and other direct superclasses which are
abstract or auxiliary object classes."

Regards,
Kathy Dally



Hallvard B Furuseth wrote:

> Kurt D. Zeilenga writes:
> > For instance, it is quite clear in X.501 that which auxiliary
> > classes an entry can belongs to is controlled solely by the
> > DIT Content Rule.  However, the entry's structural object
> > class has a auxiliary super class, then the entry belong to
> > that auxiliary class even when the DIT content rule disallows
> > it from belong to that auxiliary class.
>
> I guess that would mean that an entry of that structural object class
> cannot be created unless a DIT content rule allows the auxiliary class.
>
> --
> Hallvard