Re: [xacml] is-present-designators (fwd)

[Polar Humenn <polar@syr.edu>]

On Tue, 5 Nov 2002, Polar Humenn wrote:

> There is a way to test if attribute is present without using is-present-designator elements:
> It is to compare bag size selected by the designator to 0:
>
> <apply function-id="integer-greater-than">
>     <apply function-id="type-bag-size">
>         <attribute-designator ..../>
>     </apply>
>     <attr-val ...>0</attr-val>
> </apply>

Well, I do agree that is a way, but still it may not be all that
efficient.

Let's say you have an attribute named "face-print" that contains 2MB of
image data. You might have 10 of them.  If you just want to know if its
present, using the IsPresent element just may require the request context
builder to just see if its there. The comparing the bag size would require
the AttributeDesignator, which would actually retrieve them for nothing.

-Polar





>
> My proposal is to drop is-present-attribute-designators
>
> Simon
>
>