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RE: NEW ISSUE :Clarify usage of assertions with no behavioral requirements on the requester

From: Yalcinalp, Umit <umit.yalcinalp@sap.com>
Date: Tue, 7 Nov 2006 05:46:27 -0800
Message-ID: <2BA6015847F82645A9BB31C7F9D641650293D13D@uspale20.pal.sap.corp>
To: "Sergey Beryozkin" <sergey.beryozkin@iona.com>, <public-ws-policy@w3.org>
Please note that wsp:include only applies during the intersection (after
normalization) and after alternatives are determined. 
 
Thus, there is no change in the usage of wsp:optional as it stands
today. Therefore, just as before, the assertion marked with wsp:optional
will appear in one of the alternatives. 
 
I believe this approach does fit into your view of the problem 3789,
because it affects the vocabulary in contrary to optional. I believe it
is an extension to the provider-only markup in proposal 3. 
 
I am not in favor of Proposal 1. 
 
--umit
 


________________________________

	From: Sergey Beryozkin [mailto:sergey.beryozkin@iona.com] 
	Sent: Monday, Nov 06, 2006 9:54 AM
	To: Yalcinalp, Umit; public-ws-policy@w3.org
	Subject: Re: NEW ISSUE :Clarify usage of assertions with no
behavioral requirements on the requester
	
	
	Hi Umit
	 
	Can you please give few simple examples on how wsp:optional and
wsp:include (targeting various types of assertions) can be used at the
same time...
	 
	Thanks, Sergey
	
	

		Folks, 

		Here is my proposal to close issues [3789] and [3721].
Call it proposal 5. 

		I am including here only the changes that will impact
the framework. There has been quite a discussion on the use cases for
both of these issues. I will be happy to draft text to illustrate the
use of the attribute if we accept the proposal for specifically the
guidelines document and the primer. Since we are trying to close all the
issues on the framework, I targeted text for this section only. Note
that for the configuration parameters, only the providers tools will
understand them. For those which have no behavioral requirements and not
affect the wire, the client can choose to understand the vocabulary. 

		IMO, this proposal has the advantage of addressing
different uses of an assertion, allows different consumers to be able to
include them into their intersection algorithm, allows the provider only
or client tools to process intersections in a uniform way and thus
satisfies both the issues at hand with a minimum disruption to the
framework. 

		If you think we should include a "default" value to the
attribute and assume all assertions exhibit a predetermined value to
target all consumers, I am open to that. However, the way I wrote it,
the assertions that do not have this attribute do get included into the
alternative vocabulary so, that would be an addition which may not be
necessary. 

		Note that I am not tied to the name of the attribute. If
you want to call it mustUnderstand, I do not care, but I like my name
better. These assertions are included only when the consumer understands
them. 

		[3789]
http://www.w3.org/Bugs/Public/show_bug.cgi?id=3789
<http://www.w3.org/Bugs/Public/show_bug.cgi?id=3789> 

		[3721]
http://www.w3.org/Bugs/Public/show_bug.cgi?id=3721
<http://www.w3.org/Bugs/Public/show_bug.cgi?id=3721> 

		--------------------------------

		Here is the proposal: 

		Section 3.1: Add the following section

		3.1.1 wsp:include attribute information item 

		WS-Policy framework provides a global attribute
information item to enable authors to selectively designate the
consumers of the assertion based on the value of the attribute. 

				A [local name] of include .

				A [namespace name] of
"http://www.w3.org/@@@ <http://www.w3.org/@@@> ".

			The type of the include attribute information
item is a list xs:anyURI. Its actual value MUST be an absolute IRI as
defined in [IETF RFC 3987 <outbind://85/l%20RFC3987> ]. 

			The presence of this attribute indicates that
the assertion is targeted to a specific set of consumers for processing
this attribute. Although the type of the assertion is part of a policy
expression's vocabulary it appears, however it is only utilized by
targeted consumers for intersection [See Section 4.4 Policy
Intersection]. Authors should not utilize this attribute for assertions
that are required for interoperability targeted to all consumers. 

			Changes to Section 4.4 

			Replace the paragraph: 

		{As a first approximation, an algorithm is defined
herein that approximates compatibility in a domain-independent manner;
specifically, for two policy alternatives
<outbind://85/l%20policy_alternative>  to be compatible, they must at
least have the same policy alternative vocabulary
<outbind://85/l%20policy_alternative_vocabulary>  (see Section 3.2
Policy Alternative <outbind://85/l%20rPolicy_Alternative> ).}

		With the following/Make this sentence a paragraph:

		{As a first approximation, an algorithm is defined
herein that approximates compatibility in a domain-independent manner;
specifically, for two policy alternatives
<outbind://85/l%20policy_alternative>  to be compatible, they must at
least have the same policy alternative vocabulary
<outbind://85/l%20policy_alternative_vocabulary>  (see Section 3.2
Policy Alternative <outbind://85/l%20rPolicy_Alternative> ) subject to
the assertions that are present in an alternative that are marked with
wsp:include attribute in the vocabulary. Each assertion that uses
wsp:include attribute is included in the alternative only if a consumer
of the alternatives (for example, a requestor) handling the intersection
understands the value of the wsp:include URI value. Otherwise, the
assertion type is not considered part of the alternative. The following
rules apply after this processing: }

		

		----------------------

		Dr. Umit Yalcinalp

		Architect

		NetWeaver Industry Standards

		SAP Labs, LLC

		Email: umit.yalcinalp@sap.com Tel: (650) 320-3095 

		SDN:
https://www.sdn.sap.com/irj/sdn/weblogs?blog=/pub/u/36238
<https://www.sdn.sap.com/irj/sdn/weblogs?blog=/pub/u/36238> 

		--------

		"First they ignore you, then they ridicule you, then
they fight you, then you win." Gandhi

		"You die. Gandhi was an optimist" Roberto Chinnici


________________________________

			From: public-ws-policy-request@w3.org
[mailto:public-ws-policy-request@w3.org] On Behalf Of Sergey Beryozkin
			Sent: Wednesday, Nov 01, 2006 10:42 AM
			To: Sergey Beryozkin; public-ws-policy@w3.org
			Subject: Re: NEW ISSUE :Clarify usage of
assertions with no behavioral requirements on the requester
			
			
			Hello
			 
			I'd just like to explore a Proposal3 below in a
bit more detail, copying it here for convenience :
			 
			Proposal 3. Introduce a new attribute
wsp:provider-only and leave wsp:optional the way it is now.
			 
			Ex :
			 
			<Policy>
			<m:MTOM wsp:optional="true"/>
			<sp:security/>
			<!-- of potential interest to requesters -->
			<m:highlyAvailable wsp:provider-only="true"/>
			<!-- server-specific stuff, of no interst to
requesters-->
			<m:myCustomServerLogging
wsp:provider-only="true"/>
			</Policy>
			 
			I'd like to remove server-only private stuff
from here and concentrate only on capabilities which can be of interest
to clients. Additionally, just for the purpose of this example I'll use
wsp:advisory instead of wsp:provider-only because I just like
wsp:advisory the name :-). Lets assume for a sec wsp:advisory is good
for advertizing capabilities which can be ignored, server-specific stuff
does not go here at all :
			 
			<Policy>
			<m:MTOM wsp:optional="true"/>
			<sp:security/>
			<!-- of potential interest to requesters -->
			<m:replicatable wsp:advisory="true"/>
			</Policy>
			 
			Normal form :
			 
			
			<Policy>
			<ExactlyOnce>
			<All>
			  <m:MTOM/>
			  <sp:security/>
			  <m:replicatable wsp:advisory="true"/>
			</All>
			<All>
			  <sp:security/>
			  <m:replicatable wsp:advisory="true"/>
			</All>
			</ExactlyOnce>
			</Policy>
			 
			With wsp:optional we only mark optional
assertions with some behaviours a requester will need to do.
			With wsp:advisory we only mark things a
requester may choose either to notice or ignore. Note that in the case
of
			 
			I've thought more about it. I feel that it's
kind of nice to have this separation of concerns. It makes sense.
However I'm not sure that it makes things simplier/less unambiguous and
confusing from a practical perspective :
			 
			* there's some overlap here in that both
<m:MTOM/> and <m:replicatable/> are assertions a requester may
optionally ignore. I just feel it will cause a lot a lot of confusion
for users to figure out what should be marked as wsp:optional and
wsp:replicatable (and then withsome standard wsp:local attribute marking
pure server-only assertions :-)). I think the above example shows
there's some ambiguity in  how <m:replicatable wsp:advisory="true"/>
should be interpreted, it is in the alternative, but at the same time
it's not because it can be ignored, it kind of dilutes the meaning of
alternative.
			 
			* people would still be able to make
<m:replicatable/> with wsp:optional
			* people would likely start marking server-only
assertions like <m:myCustomServerLogging/> with wsp:advisory/as well as
with wsp:optional.
			* it's not clear what a requester seeing
<m:replicatable wsp:advisory="true"/> should do if does not understand
what it means : just ignore it, or ignore it and warn a user ? 
			* it's not clear what a requester seeing
<m:myCustomServerLogging wsp:advisory="true"/> should do if does not
understand what it means : just ignore it, or ignore it and warn a user
? this is an example of misused <m:myCustomServerLogging/> 
			* I think it will slow down the requester's
processing because even though <m:replicatable wsp:advisory="true"/> is
marked as something which can be ignored a requester will still to
process it and check if it's something it actually understands or not...
			 
			So far Proposal1 with a possible renaming to
wsp:ignorable (and controversial 2 :-)) or Proposal4 (workaround) work
for me...they just seem simplier, don't really require to do anything
major. I'm not sure adding a new attribute will simplify/clarify things
but lets think more Proposal3 too...
			 
			And I can't help waiting reading a Proposal 5
from Umit :-)
			 
			Enjoy
			Sergey
			 
			 
			 

				
				
				Hello,
				 
				As part of the action assigned to me at
the yesterday's concall, I'd like to offer to your attention 4
alternative proposals on how to resolve this issue which I believe have
been mentioned before. I hope the subsequent discussions will point to a
best/preferred/least controversial/simpliest/easy to understand
solution. 
				 
				I'd like to clarify that the purpose of
resolving this issue is to have a guideline to policy authors which wish
to advertize some of provider's capabilities. For ex, custom:free,
custom:infoConfidential, custom:highlyAvailable, custom:replicatable
which requesters can ignore or do something about.
				I'll add my own comments (S.B) to each
of the proposal. However, please do not consider them as something which
represents the position of Iona at this stage.
				 
				 
				Proposal1.
				Drastically simplify the meaning of
wsp:optional. Explain that wsp:optional marks an assertion which can be
ignored by a requester. In other words wsp:optional is identical in
meaning to wsp:ignorable. Clearly state that wsp:optional assertions are
by no means optional to a provider. 
				Explain that wsp:optional is a shortcut
which simplifies creating different policy alternatives/vocabularies.
				Ex : <custom:infoConfidential
wsp:optional="true"/> means a requester can ignore it.
				 
				 
				<S.B>  IMHO this is the simpliest
solution which works. IMHO the current treatment of wsp:optional is too
complicated. For ex, I think stating that if there's something a
provider always does should not be marked as optional, otherwise it has
to be optional will only confuse the users. IMHO it's wrong to say a
provider optionally does MTOM, it always does it, one requester can
choose an alternative with no MTOM but it does not mean the provider
does not do it with the other requester. In other words an alternative
is a piece of vocabulary. If MTOM is not in the selected alternative or
not it does not mean that a provider has lost its capability to do MTOM.
Viewing wsp:optional as a simple marker to indicate ignorable assertions
is a very simple and working solution IMHO.
				<S.B> additional advantage is that it
cleanly alligns with a proposed wsp:local attribute in that a user will
be guided to mark server-specific stuff as being wsp:local. Imagine a
GUI asking a question : 
				* "Is this assertion must be understood
by a requester", YES-normal assertion.
				* "Is this assertion may be ignored by a
requester", YES-multiple vocabularies are created, addional question :
"Can this ignorable assertion be of any interest to a requester ?" NO -
mark it as wsp:local.
				Nothing will prevent a user by exposing
<myLocalServerOnlyAssertion/> by marking it as wsp:optional. This
approach will proactively teach a user not to do it and only expose
assertions which can be of interest to a requester.
				 
				Proposal 2. Similar to proposal1. Drop
wsp:optional altogether and find out how simple things have become. The
reason it works is that if we forget about wsp:optional for a second, we
can easily see that if one assertion is contained in one alternative and
not in the other one then it's an optional/ignorable assertion. Another
reason it works is that we can imagine policy authors using GUI tools
which guide them. Imagine questions like : "Is this assertion must be
understood by a requester" ? "Is this assertion may be ignored by a
requester" ? Yes to the last question will result in a tool creating two
alternative vocabularies.
				 
				<S.B> the same comments as above
				<S.B> disadvantage is that more work
will be requiored in a manual edit mode.
				 
				Proposal 3. Introduce a new attribute
wsp:provider-only and leave wsp:optional the way it is now.
				 
				Ex :
				 
				<Policy>
				<m:MTOM wsp:optional="true"/>
				<sp:security/>
				<!-- of potential interest to requesters
-->
				<m:highlyAvailable
wsp:provider-only="true"/>
				<!-- server-specific stuff, of no
interst to requesters-->
				<m:myCustomServerLogging
wsp:provider-only="true"/>
				</Policy>
				 
				<S.B.> This works only if
wsp:provider-only="true" are not stripped but this means
wsp:provider-only="true" pointing to server-specific stuff only won't be
stripped and be consistently leaked (and confuse a user at a
design-time). If it's stripped then we'll lose <m:highlyAvailable/>
which is of interest to knowledgeable requesters. IMHO it's a can of
worms. 
				 
				Proposal 4. Noop. Think of workarounds :
multiple endpoints, different Policies, WSDLs, etc...
				 
				 
				Enjoy, Sergey.
				 
				 
				 
				 
				 
				 
Received on Tuesday, 7 November 2006 13:47:12 GMT

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