[xacml] XML schema annotation

[Sekhar Vajjhala - Sun Microsystems <sekhar.vajjhala@sun.com>]

Hi,

Since the subject of using <annotation> came up in the
TC meeting, I thought this would be educational to send
out a little bit more information about it.

The <annotation> element is specified by XML Schema Part 1
specification. It is however meant to be used in annotating 
a schema (e.g XACML schema itself) not an XML instance document.

It can be used can be used with most XML schema components.
(the precise location is determined by XML Schema Part 1
specification).

An <annotation> can contain two XML sub elements:

1. <appinfo> which contains information meant for consumption by
   an application. So for e.g., this could be used to attach
   business level constraints ( e.g. Schematron rules ). 

2. <documentation> sub element which contains information meant
   for human consumption.

-- 
Sekhar