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ACTION-294 Ashok to open a CR issue with text to define "collection"

From: Ashok Malhotra <ashok.malhotra@oracle.com>
Date: Fri, 4 May 2007 05:29:13 -0700
To: "public-ws-policy@w3.org" <public-ws-policy@w3.org>
Message-ID: <20070504052913953.00000009940@amalhotr-pc>
My point was that the word 'collection' in Computer Science is used as a generic term to cover several types of collections.
See definition from Wikipedia below.  Thus, it would be better to be more precise about the exact type of collection we use in WS-Policy:

In  HYPERLINK "http://en.wikipedia.org/wiki/Object-oriented_programming" \o "Object-oriented programming" object-oriented programming, a collection class is any  HYPERLINK "http://en.wikipedia.org/wiki/Class_%28computer_science%29" \o "Class (computer science)" class that is capable of storing other  HYPERLINK "http://en.wikipedia.org/wiki/Object_%28computer_science%29" \o "Object (computer science)" objects. Collection classes usually implement some kind of  HYPERLINK "http://en.wikipedia.org/wiki/Data_structure" \o "Data structure" data structure, such as a  HYPERLINK "http://en.wikipedia.org/wiki/List_%28computing%29" \o "List (computing)" list,  HYPERLINK "http://en.wikipedia.org/wiki/Associative_array" \o "Associative array" map,  HYPERLINK "http://en.wikipedia.org/wiki/Set_%28computer_science%29" \o "Set (computer science)" set,  HYPERLINK "http://en.wikipedia.org/wiki/Array" \o "Array" array, or  HYPERLINK "http://en.wikipedia.org/wiki/Tree_%28data_structure%29" \o "Tree (data structure)" tree. A collection class is usually able to store an arbitrary number of data items, i.e. the size of the collection is adjusted automatically.

In the framework document we use 'collection' in three contexts:

"A  HYPERLINK "http://www.w3.org/TR/2007/CR-ws-policy-20070330/" \l "policy" \o "policy" policy is a collection of policy alternatives."  Since alternatives can be identical and there is no order between them, a policy is a bag of alternatives.
"A  HYPERLINK "http://www.w3.org/TR/2007/CR-ws-policy-20070330/" \l "policy_alternative" \o "policy alternative" policy alternative is a collection of policy assertions."  Here, again, the assertions in an alternative can be duplicates and are unordered, so bag seems to be the correct term.
"A  HYPERLINK "http://www.w3.org/TR/2007/CR-ws-policy-20070330/" \l "policy_scope" \o "policy scope" policy scope is a collection of policy subjects to which a policy applies."  Here I am not sure.  Can there be duplicate subjects in a policy scope?  Aren't policy subjects ordered?

If the policy subjects in a policy scope can be duplicates and are not ordered then all uses of 'collection' mean 'bag' and we can add a definition such as "In this document the word 'collection' refers to what is known in the literature as 'bag'.  But I thought we should clarify point 3 first.

All the best, Ashok
Received on Friday, 4 May 2007 12:30:00 GMT

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