[xacml-comment] Schema error (Section 6.7 says that <AttributeValue>is optional)

[Satoshi Hada <SATOSHIH@jp.ibm.com>]

Anne,

Section 6.7 says that <AttributeValue> in
<Attribute> is OPTIONAL. Actually, minOccurs="0" is specified.

However,
the minOccurs="0" is missing
in the schema in the conformance testcases.

I have a question here.
Take for example the following "action-param" attribute
with no attribute value specified.

<?xml version="1.0" encoding="UTF-8"?>
<Request>
    ...
    <Action>
        <Attribute
          AttributeId="urn:oasis:names:tc:xacml:1.0:action:action-param"
          DataType="http://www.w3.org/2001/XMLSchema#anyURI"/>
    </Action>
    ...
</Request>

Does this mean that
the "action-param" attribute is ABSENT,
or
the "action-param" attribute is PRESENT, but the attribute value
is missing.

In my understanding, I think it means the latter, and
my understanding of "MustBePresent" of <AttributeDesignator>
is as follows:
Is this correct?
In particular, Is my understanding for Case 2-1 correct?

AttributeDesignator:
(Case 1) The designated attribute was absent
  If(MustBePresent=TRUE)
    The result is "Indeterminate".
  else
    The result is an empty bag.
(Case 2) The designated attribute was present
  (Case 2-1) It was an empty bag.
    Regardless of the MustBePresent value, the result is the empty bag.
  (Case 2-2) It was a non-empty bag.
    Regardless of the MustBePresent value, the result is the non-empty bag.


Satoshi Hada
IBM Tokyo Research Laboratory
mailto:satoshih@jp.ibm.com