[xacml-comment] SubjectCategory XML attribute:string or URI?

I recommend we change the type of the SubjectCategory XML
attribute in both the Policy and, based on the 12/02/02 change,
in the Context.

RATIONALE:

All the values we have defined for SubjectCategory are URIs.  It
is very important that custom SubjectCategory values not collide
with each other.  When subject-category was an XACML attribute,
it probably made sense for the Policy SubjectCategory XML
attribute to be a string since we specified that string-equals
comparison was to be done.  But the actual syntax of the
SubjectCategory value should be something that is likely to be
unique, and can be made not to collide with other values, and now
that we are specifying that syntax, I believe it should be a URI.

Anne
-- 
Anne H. Anderson             Email: 
Sun Microsystems Laboratories
1 Network Drive,UBUR02-311     Tel: 781/442-0928
Burlington, MA 01803-0902 USA  Fax: 781/442-1692