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RE: NEW ISSUE 4138: Normalization Algorithm is broken

From: Yalcinalp, Umit <umit.yalcinalp@sap.com>
Date: Mon, 15 Jan 2007 10:35:38 -0800
Message-ID: <2BA6015847F82645A9BB31C7F9D641650324144C@uspale20.pal.sap.corp>
To: "Asir Vedamuthu" <asirveda@microsoft.com>, <public-ws-policy@w3.org>
Asir, 
 
Instead of thinking of "what is the minimum change", I would like to
approach it as to "what is the expected result" first and then find out
how we can achieve it. 
 
Could you tell me first what the normalized form of 
 
<wsp:Policy>
      <wsap:UsingAddressing/>
</wsp:Policy>
 
is? 
 
Lets go from there. "Construct a normal form" for this does not really
follow and indicate what the result should be. 
 
Thanks, 
 
--umit
 


________________________________

	From: Asir Vedamuthu [mailto:asirveda@microsoft.com] 
	Sent: Sunday, Jan 14, 2007 10:59 PM
	To: Yalcinalp, Umit; public-ws-policy@w3.org
	Subject: RE: NEW ISSUE 4138: Normalization Algorithm is broken 
	
	

	>Thus, readers following the Framework with 

	>the primer document and trying to formulate

	>a normal form will not be able to get what 

	>they want.

	 

	First, thank you for carefully reviewing the normalization
algorithm and manually working out an example (this is equivalent to
running a unit test).

	 

	We looked into interop test cases. There are many test cases
that use the form <Policy><wsap:UsingAddressing /></Policy> in the
contributed interop scenarios pack [1]. Several implementers ran these
test cases. The good news is that there aren't any related interop
issues.

	 

	Framework document says [2], "4. Apply the policy operator
indicated by D to the normalized Element Information Items in its
[children] property and construct a normal form per Section 4.3.3 Policy
Operators."

	 

	In the above sentence, 'construct a normal form' is the key
phrase and it refers to the normal form in Section 4.1 [3]. Section 4.1
XML outline and prose describe how a policy alternative in the normal
form looks like. To help readers make this connection, we suggest that
the normalization algorithm carry an explicit reference to the normal
form. This means, the proposed change is:

	 

	s/4. Apply the policy operator indicated by D to the normalized
Element Information Items in its [children] property and construct a
normal form per Section 4.3.3 Policy Operators./4. Apply the policy
operator indicated by D to the normalized Element Information Items in
its [children] property and construct a normal form per Section 4.3.3
Policy Operators and 4.1 Normal Form Policy Expression./

	 

	We belive that the above proposed change is the minimum needed
to resolve issue 4138 [4].

	 

	[1]
http://lists.w3.org/Archives/Public/public-ws-policy/2006Jun/0010.html
<http://lists.w3.org/Archives/Public/public-ws-policy/2006Jun/0010.html>


	[2]
http://www.w3.org/TR/2006/WD-ws-policy-20061117/#Compact_Policy_Expressi
on
<http://www.w3.org/TR/2006/WD-ws-policy-20061117/#Compact_Policy_Express
ion>  

	[3]
http://www.w3.org/TR/2006/WD-ws-policy-20061117/#Normal_Form_Policy_Expr
ession
<http://www.w3.org/TR/2006/WD-ws-policy-20061117/#Normal_Form_Policy_Exp
ression> 

	[4] http://www.w3.org/Bugs/Public/show_bug.cgi?id=4138
<http://www.w3.org/Bugs/Public/show_bug.cgi?id=4138>  

	 

	Regards,

	 

	Asir S Vedamuthu

	Microsoft Corporation

	 

	 

	 

	 

	From: public-ws-policy-request@w3.org
[mailto:public-ws-policy-request@w3.org] On Behalf Of Yalcinalp, Umit
	Sent: Tuesday, January 02, 2007 11:58 AM
	To: public-ws-policy@w3.org
	Subject: NEW ISSUE: Normalization Algorithm is broken 

	 

	Title: Normalization Algorithm is broken 

	Description: The Normalization Algorithm in the WS-Policy
framework is broken in converting a single expression of conjuncts in
compact form to an equivalent expression normal form and does not lead
to a normal form expression as illustrated below.

	For expressions of the following form where the wsp:Policy
element may have single element child, or a multiple element children
composition with wsp:All such as: 

	<wsp:Policy> 
	    <ex:Assertion1/> 
	</wsp:Policy> 

	or 

	<wsp:Policy> 
	    <wsp:All> 
	       <ex:Assertion1/> 
	       <ex:Assertion2/> 
	    </wsp:All> 
	</wsp:Policy> 

	The normalization algorithm fails to convert this into an
equivalent expression. It would be expected to derive a normal form
expression with a single alternative of the form from such expressions. 

	<wsp:Policy> 
	    <wsp:ExactlyOne> 
	       <wsp:All> 
	            List of Assertions 
	       </wsp:All> 
	    </wsp:ExactlyOne> 
	</wsp:Policy> 

	but the algorithm fails to do so. 

	In both cases, there is no wsp:optional attribute to introduce
two alternatives into the resulting expression converted to the normal
form. Thus, no wsp:exactlyOne is introduced in this case, and the
resulting expression can not be normalized. 

	Note that the primer [1] uses such an example for the use of
WS-Addressing in Example 2.2. Thus, readers following the Framework with
the primer document and trying to formulate a normal form will not be
able to get what they want. I will illustrate the result using the
following example: 

	<Policy> 
	  <wsap:UsingAddressing /> 
	</Policy> 

	Taking the first form (a single child element) as an example,
here is the rundown of the normalization algorithm: 

	 

		1.	Start with the [document element] property D of
the Document Information Item of the policy expression. The [namespace
name] of D is always "http://www.w3.org/2006/07/ws-policy
<http://www.w3.org/2006/07/ws-policy> ". In the base case, the [local
name] property of D is "Policy"; in the recursive case, the [local name]
property of D is "Policy", "ExactlyOne", or "All". 
		2.	Expand Element Information Items in the
[children] property of D that are policy references per Section 4.3.5
Policy Inclusion <file:///\\l%20> . 
		3.	Convert each Element Information Item C in the
[children] property of D into normal form. 

				1.	If the [namespace name] property
of C is "http://www.w3.org/2006/07/ws-policy
<http://www.w3.org/2006/07/ws-policy> " and the [local name] property of
C is "Policy", "ExactlyOne", or "All", C is an expression of a policy
operator; normalize C by recursively applying this procedure. 
				2.	Otherwise the Element
Information Item C is an assertion; normalize C per Sections 4.3.1
Optional Policy Assertions <file:///\\l%20>  and 4.3.2 Policy Assertion
Nesting <file:///\\l%20> . 

		4.	Apply the policy operator indicated by D to the
normalized Element Information Items in its [children] property and
construct a normal form per Section 4.3.3 Policy Operators
<file:///\\l%20> . 

	 

	Here is what happens if you follow this step by step. 

	1. applies <wsp:Policy> 
	2. does not apply 
	3. The element information item C is wsap:UsingAddressing. 
	    4. does not apply 
	    5.  there is nothing to normalize (as 4.3.1, or 4.3.2 does
not apply) 
	6. The policy operator indicated by D is wsp:Policy which is
equivant to "wsp:All" 

	    "Applying" wsp:All to wsaw:UsingAddressing is 

	     <wsp:All><wsaw:UsingAddressing/></wsp:All> 

	     There is no optional assertion, etc. Thus, <wsp:exactlyOne>
is not introduced anywhere per the rules of the algorithm. 

	The resulting Expression is 

	     <wsp:All><wsaw:UsingAddressing/></wsp:All> 

	This is not in normal form!!! 

	It is noted that it is impossible to convert an assertion which
does not have an wsp:optional attribute to a normal form. This appears
to be a deficiency of the algorithm, and not its intention. This is a
bug in the framework. 

	Justification: 

	A common form of the expression is expected to work without the
presence of wsp:optional attribute. It is possible to create such
expressions using the policy framework. As a matter of fact, the example
is from our own primer document itself. The algorithm should work for
simple cases when single alternatives are intended by compact form as
well as complicated cases where alternatives are introduced by the
presence of the wsp:optional attribute implicitly. The algoritm should
not assume the presence of wsp:optional to introduce alternatives. 

	Proposal: 

	Add another step for the normalization algorithm along the lines
of 

	7. If the resulting expression contains no alternatives, the
expression is equivalent to a policy with a single alternative where the
content of the resulting expression comprises its content.

	 

	This issue is filed as [Bug 4138] with the content that is
provided above. 

	 

	[1] http://www.w3.org/TR/2006/WD-ws-policy-primer-20061018/
<http://www.w3.org/TR/2006/WD-ws-policy-primer-20061018/>  
	[Bug 4138] http://www.w3.org/Bugs/Public/show_bug.cgi?id=4138
<http://www.w3.org/Bugs/Public/show_bug.cgi?id=4138>  

	 

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

	Dr. Umit Yalcinalp 
	Research Scientist 
	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>  
	-------- 
	"Nearly all men can stand adversity, but if you want to test a
man's character, give him power." Abraham Lincoln. 

	 
Received on Monday, 15 January 2007 18:34:33 GMT

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