[xacml] Attribute, AttributeDesignator, AttributeSelector

I'm trying to sum up where I think we stand on the question of
Attribute, AttributeDesignator, and AttributeSelector.  Does
anyone object to the following?

There are just "Attribute"s and "AttributeSelector"s.  There is
no AttributeDesignator.  That is replaced by AttributeSelector.

Attributes are primarily used in the context to convey attribute
values, but may also occur in a policy to convey a literal value
for matching.

The Attribute schema is:

	<xs:complexType name="AttributeType">
		<xs:sequence>
			<xs:element name="AttributeMetaData" type="xacmlContext:AttributeMetaDataType"/>
			<xs:element ref="xacml:AttributeValue" maxOccurs="unbounded"/>
		</xs:sequence>
	</xs:complexType>
	<!-- -->
	<xs:complexType name="AttributeMetaDataType">
		<xs:attribute name="AttributeName" type="xs:string" use="required"/>
		<xs:attribute name="AttributeNamespace" type="xs:anyURI" use="required"/>
		<xs:attribute name="Issuer" type="xs:anyURI" use="optional"/>
		<xs:attribute name="IssueInstant" type="xs:dateTime" use="optional"/>
	</xs:complexType>
  
	<xs:element name="AttributeValue" type="xs:anyType"/>

An AttributeSelector is used only in a policy (perhaps calling it
"RequestValueSelector" would be more intuitive).  It is an XPATH
into the Request context.  We may allow the root of the XPATH to
be specified as "Subject", "Resource", "Action", "Other" as a
shortcut for "/Request/Subject/", etc.

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