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RE: comments on WS Desc Requirements draft of 29 April 2002

From: Jeffrey Schlimmer <jeffsch@windows.microsoft.com>
Date: Thu, 10 Oct 2002 08:22:22 -0700
Message-ID: <2E33960095B58E40A4D3345AB9F65EC109355C33@win-msg-01.wingroup.windeploy.ntdev.microsoft.com>
To: "WS-Desc WG (Public)" <www-ws-desc@w3.org>

In [1], we received several comments on the 29 April Requirements draft
[2]. I have incorporated several of the minor points of feedback in the
working draft [3], and below are some more substantial points of
feedback along with my recommendation.

--Jeff

[1]
http://lists.w3.org/Archives/Public/public-ws-desc-comments/2002Sep/0001
.html 
[2] http://www.w3.org/TR/2002/WD-ws-desc-reqs-20020429/ 
[3]
http://dev.w3.org/cvsweb/~checkout~/2002/ws/desc/requirements/ws-desc-re
qs.html 


COMMENT
1 "action" is undefined (I realize one can't define every term in every
definition -- perhaps specs should provide both definitions and explicit
lists of important primitive concepts), and the result is that I don't
know what is actually meant here. 

RECOMMENDATION
Use a better definition from the TAG, if any.


REQUIREMENT
R014 
The WG specification(s) SHOULD be compatible with existing Web
infrastructure. (From the Charter. Last discussed 7 Mar 2002.)

COMMENT
R014 seems vague.  It would be helpful to the reader if it were possible
to indicate in a sketchy manner which parts of the existing Web
infrastructure are meant here: existing deployed WSDL 1.1 software?
REST-ful software and ideas? HTML 3.2?  I realize that this is likely to
be a difficult point to reach perfect consensus on; perhaps a note
indicating the degree of consensus and the points of contention would be
useful. 

RECOMMENDATION
(No change.) R014 comes directly from the charter. It is a general
goodness requirement and is harmless.


REQUIREMENT
R054 
The description language MUST clearly separate the description of
Messages from the Message exchange pattern and InterfaceBinding. (From
YF. Last revised 11 April 2002.)

COMMENT
R054 is opaque to me: as a reader, I don't know what is meant here, or
how I would tell the difference between a Web Services Description spec
that met this requirement and one which didn't. 

RECOMMENDATION
Reword: "The description language MUST describe Messages independent
from their use in message exchange patterns and/or Interface Bindings."


REQUIRMENT
R116 
The description language MUST allow describing abstract policies
required or offered by Services. (From GD. Last revised 11 Apr 2002.)

COMMENT
R116 sounds good, but I don't know what it means.  An example of an
abstract policy, as opposed to a concrete policy, would be helpful, as
would an example clarifying what it means to "offer" a policy. [Good
feedback.]

RECOMMENDATION
Ask contributor (Glen?) to clarify. (I don't remember exactly what we
were driving at here.)


REQUIREMENT
R046 
The description language MUST allow describing Messages independent of
specific wire format. (From JS. Last discussed 11 April, 2002.)

COMMENT
R046 leaves the term "wire format" undefined.  I have heard this term
often before, but never before in a context where the details of what is
meant matter quite so much.  A definition or at least an example would
be useful.  (Big-endian vs. little-endian? HTTP vs. SMTP?  ASCII vs
UTF-7 vs UTF-8 vs Shift-JIS vs EBCDIC vs UTF-16?  All of the above? None
of the above?)

RECOMMENDATION
Reword: "The description language MUST describe Messages independent
from transfer encodings." or "The description language MUST describe
Messages in terms of the XML Infoset."


REQUIREMENT
R071 
The description language MUST allow partitioning a description across
multiple files. (From JS.)

COMMENT
R071 puzzles me slightly.  If the description is in XML, as is implied
by your definition of Web Service, then this is already given by the
existence of the external-entity mechanism in XML.  If the
external-entity mechanism of XML does not meet this requirement, then it
is not clear what the requirement is, and this item needs revision.

RECOMMENDATION
(No change.) We need a mechanism that allows changes to the WSDL
component model in the way that XSD include/import does. 


REQUIREMENT
R012 
The description language MUST support the kind of extensibility actually
seen on the Web: disparity of document formats and protocols used to
communicate, mixing of XML vocabularies using XML namespaces,
development of solutions in a distributed environment without a central
authority, etc. In particular, the description language MUST support
distributed extensibility. (From the Charter. Last discussed 12 April
2002.)

COMMENT
R012 uses but does not define the term "support", which means the
statement of the requirement is not really very informative.

RECOMMENDATION
(No change.) A general requirement from the charter that is refined in
other requirements. 


REQUIREMENT
R067 
The description language MUST have adequate points of extension in its
constructions. (From WG discussion. Last discussed 12 Apr 2002.)

COMMENT
R067 uses the term "points of extension", which should perhaps be
defined (I don't know what it means).

RECOMMENDATION
Reword: "The description language MUST allow for extension in 


REQUIREMENT
R115 
The WG specification(s) SHOULD define the equivalence of Service
descriptions. (From SW. Last discussed 11 April 2002.)

COMMENT
R115 appeals to a notion of equivalence, but the meaning of
"equivalence" is not clear here.  Do you mean that the WG
specification(s) SHOULD define an equivalence relation on Service
descriptions?  Or are you appealing to an existing notion of such an
equivalence relation, and saying that the spec(s) should be sure to do
something (what?) about it?

RECOMMENDATION
Reword: The WG specification(s) SHOULD define an equivalence relation on
Service descriptions."

EOF
Received on Thursday, 10 October 2002 11:22:56 GMT

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