- From: ashok malhotra <ashok.malhotra@oracle.com>
- Date: Thu, 14 May 2009 16:01:21 -0700
- To: Geoff Bullen <Geoff.Bullen@microsoft.com>
- CC: Doug Davis <dug@us.ibm.com>, "public-ws-resource-access@w3.org" <public-ws-resource-access@w3.org>
> Wouldn’t this mean that this policy assertion is being automatically added to the XPath2 namespace? No, it identifies the filter dialect as being XPath2. All the best, Ashok Geoff Bullen wrote: > > Thanks for the clarification Doug. > > <x:FilterDialect xmlns:x=".../XPath2"/> > > Wouldn’t this mean that this policy assertion is being automatically > added to the XPath2 namespace? > > What if the “…/Xpath2” namespace already includes FilterDialect? > > More generally, are you not saying that if someone can think of a > reason why they might use a particular spec A as a filter for > Enumeration or Eventing, then automatically there is now a new policy > assertion defined in spec A’s namespace? > > This appears problematic because: > > 1. You are adding something to a namespace owned and controlled by > someone else. > > 2. What about collisions? > > 3. There is no way to define or test conformance to this assertion. > > 4. There is no schema associated with this. > > Hope this helps, > > Geoff > > *From:* public-ws-resource-access-request@w3.org > [mailto:public-ws-resource-access-request@w3.org] *On Behalf Of *Doug > Davis > *Sent:* Thursday, May 14, 2009 9:06 AM > *To:* public-ws-resource-access@w3.org > *Subject:* RE: [Bug 6403] Enumeration: define policy > > > At the risk of adding more confusion, neither :-) > > My proposal is that the assertion would be: > <xFilterDialect xmlns:x=".../XPath2"/> > > the namespace URI of the element is the URI that goes into the Filter > Dialect attribute. This allows for a generic piece of code to know > which assertions are filter dialects (instead of something else) and > to know exactly what the URI for the attribute would be. > > Having a URI attribute (like both of your alternatives show) would (I > believe) lead to domain specific processing for policy matching - and > that's something I think we should avoid. > > thanks > -Doug > ______________________________________________________ > STSM | Standards Architect | IBM Software Group > (919) 254-6905 | IBM 444-6905 | dug@us.ibm.com > The more I'm around some people, the more I like my dog. > > *Geoff Bullen <Geoff.Bullen@microsoft.com>* > > 05/14/2009 11:59 AM > > > > To > > > > Doug Davis/Raleigh/IBM@IBMUS, "ashok.malhotra@oracle.com" > <ashok.malhotra@oracle.com> > > cc > > > > "public-ws-resource-access@w3.org" <public-ws-resource-access@w3.org>, > "public-ws-resource-access-request@w3.org" > <public-ws-resource-access-request@w3.org> > > Subject > > > > RE: [Bug 6403] Enumeration: define policy > > > > > > > > Doug, > Perhaps the actual policy assertions for the Xpath2 policy assertions > would be helpful here. Our understanding is that your proposal states > the assertion has the form: > <x:FilterDialect uri="...." /> > > (Note: “optional=true” is left out from all the assertions to make > them shorter) > > Using the XPath2 example below, which assertion does this map to for > your proposal? > 1) <wsen:FilterDialect uri=".../XPath2" /> > or > 2) <mynamespace:FilterDialect uri=".../XPath2" /> > > The arguments presented appear to imply you mean option 1) as you > argue that the policy assertion would represent a “standard way” for > any end point to assert that it supports the XPath2 filter dialect. > Note the use of “wsen:FilterDialect”. > > If option 2) was correct, there would still be no “standard” known > definition for the new XPath2 assertion as you could not assume that > <a:FilterDialect uri=".../XPath2" /> and <b:FilterDialect > uri=".../XPath2" /> are the same assertion. This appears to have > little value over using “<a:XPath2FilterDialect />”. > > Option 1) implies that a new standard assertion is automatically added > to the WS-Enumeration namespace whenever a new “filter” dialect (for > example XPath2) is standardized. While the reasoning behind wanting > this is clear, as stated below this does have interop implications, > and also seems to break the rule that extensions should not use the > standard namespace. > > --Geoff > > > *From:* Doug Davis [mailto:dug@us.ibm.com] * > Sent:* Wednesday, May 13, 2009 5:37 PM* > To:* ashok.malhotra@oracle.com* > Cc:* Geoff Bullen; public-ws-resource-access@w3.org; > public-ws-resource-access-request@w3.org* > Subject:* Re: [Bug 6403] Enumeration: define policy > > > Ashok, > I think you misunderstood my reply to Geoff. I'm not saying we > shouldn't allow XPath2.0 - what I'm saying is that I don't understand > why the <XPATH2> element from Geoff's example would be in there when > it doesn't appear to be part of the XPath 2.0 expression language. > > Geoff, > you seem to be implying that new specs will need to be created to > build a link between Enum and some expression language. I wanted to > make sure you understood that people can still do that. There is > nothing stopping them from doing so. All they would need to do is > define a new namespace URI for that spec and viola, they have their > Enum filter dialect assertion. So my proposal allows for both worlds. > > thanks > -Doug > ______________________________________________________ > STSM | Standards Architect | IBM Software Group > (919) 254-6905 | IBM 444-6905 | dug@us.ibm.com > The more I'm around some people, the more I like my dog. > > *ashok malhotra <ashok.malhotra@oracle.com>* > Sent by: public-ws-resource-access-request@w3.org > > 05/13/2009 08:27 PM > > Please respond to > ashok.malhotra@oracle.com > > > > To > > > > Doug Davis/Raleigh/IBM@IBMUS > > cc > > > > Geoff Bullen <Geoff.Bullen@microsoft.com>, > "public-ws-resource-access@w3.org" <public-ws-resource-access@w3.org> > > Subject > > > > Re: [Bug 6403] Enumeration: define policy > > > > > > > > > > Doug: > XPath 2.0 is a significant change from XPath 1.0. For one, it is Schema > aware so it recognizes various datatypes > and provides many, many functions to operate on/test those datatypes. > It is, though, a new spec and may not have enough uptake just yet but we > should provide extensibility to allow for it in future versions. > All the best, Ashok > > > Doug Davis wrote: > > > > I don't understand why they would even think to put the XPath2 element > > in there. That element is not defined by the expression language. > > > > thanks > > -Doug > > ______________________________________________________ > > STSM | Standards Architect | IBM Software Group > > (919) 254-6905 | IBM 444-6905 | dug@us.ibm.com > > The more I'm around some people, the more I like my dog. > > > > > > *Geoff Bullen <Geoff.Bullen@microsoft.com>* > > > > 05/13/2009 01:15 PM > > > > > > To > > Doug Davis/Raleigh/IBM@IBMUS, "public-ws-resource-access@w3.org" > > <public-ws-resource-access@w3.org> > > cc > > > > Subject > > RE: [Bug 6403] Enumeration: define policy > > > > > > > > > > > > > > > > > > > > Doug, > > Here is a simple example that we can look at. The new XPath2 standard > > comes out and company X has an implementation of an Enumeration End > > Point that currently supports the current XPath. They choose to > > implement a new XPath2 filter message as : > > <Enumerate> > > … > > <Filter Dialect="/…/XPath2/"> > > <XPATH2> > > Xpath2 filtering syntax here > > </XPATH2> > > </Filter> > > </Enumerate> > > > > Company X is free to implement XPath2 filtering for their own end > > point in that way if they wish, but can they then use > > <x:FilterDialect xmlns:x="…/Xpath2" wsp:Optional="true"/> as a policy > > statement to advertize it? What if another company implements it > > without the XPATH2 element and advertizes the same policy? > > > > --Geoff > > > > *From:* public-ws-resource-access-request@w3.org > > [mailto:public-ws-resource-access-request@w3.org] *On Behalf Of *Doug > > Davis* > > Sent:* Tuesday, May 12, 2009 12:22 PM* > > To:* public-ws-resource-access@w3.org* > > Subject:* RE: [Bug 6403] Enumeration: define policy > > > > > > I'm not sure I understand the question. Someone can use (and interop) > > with xpath 2.0 and enum w/o a new spec - and the same can be true for > > some other expression language (not all are as complicated at xpath - > > e.g. the QName dialect in RT). The concern I have is whether or not > > it'll require a new spec just to define a QName to say that the data > > source supports it. > > > > thanks > > -Doug > > ______________________________________________________ > > STSM | Standards Architect | IBM Software Group > > (919) 254-6905 | IBM 444-6905 | _dug@us.ibm.com_ <mailto:dug@us.ibm.com> > > The more I'm around some people, the more I like my dog. > > > > *Geoff Bullen <**_Geoff.Bullen@microsoft.com_* > > <mailto:Geoff.Bullen@microsoft.com>*>* > > > > 05/12/2009 03:11 PM > > > > > > To > > Doug Davis/Raleigh/IBM@IBMUS, "_public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>" > > <_public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>> > > cc > > > > Subject > > RE: [Bug 6403] Enumeration: define policy > > > > > > > > > > > > > > > > > > > > > > > > Doug, for anything to be a “standard” there has to be some level of > > interop testing. How do you propose to do interop testing on the new > > expression language usage with Enumeration? > > * > > From:* _public-ws-resource-access-request@w3.org_ > > <mailto:public-ws-resource-access-request@w3.org> > > _[mailto:public-ws-resource-access-request@w3.org]_ > > <mailto:%5Bmailto:public-ws-resource-access-request@w3.org%5D> *On > > Behalf Of *Doug Davis* > > Sent:* Tuesday, May 12, 2009 12:05 PM* > > To:* _public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>* > > Subject:* RE: [Bug 6403] Enumeration: define policy > > > > > > sure - but would it require any new text beyond what ws-en already > > says. I'm just not so sure and I'm worry about how heavy of a burden > > we're putting on people who end up wanting to use an expression > > language that doesn't require a whole new spec. > > > > thanks > > -Doug > > ______________________________________________________ > > STSM | Standards Architect | IBM Software Group > > (919) 254-6905 | IBM 444-6905 | _dug@us.ibm.com_ <mailto:dug@us.ibm.com> > > The more I'm around some people, the more I like my dog. > > > > *Geoff Bullen <**_Geoff.Bullen@microsoft.com_* > > <mailto:Geoff.Bullen@microsoft.com>*>* > > > > 05/12/2009 03:02 PM > > > > > > > > > > To > > Bob Freund <_bob@freunds.com_ <mailto:bob@freunds.com>>, Doug > > Davis/Raleigh/IBM@IBMUS > > cc > > "_public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>" > > <_public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>> > > Subject > > RE: [Bug 6403] Enumeration: define policy > > > > > > > > > > > > > > > > > > > > > > > > > > Yes there are… > > * > > From:* _public-ws-resource-access-request@w3.org_ > > <mailto:public-ws-resource-access-request@w3.org> > > _[mailto:public-ws-resource-access-request@w3.org]_ > > <mailto:%5Bmailto:public-ws-resource-access-request@w3.org%5D> *On > > Behalf Of *Bob Freund* > > Sent:* Tuesday, May 12, 2009 12:00 PM* > > To:* Doug Davis* > > Cc:* _public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>* > > Subject:* Re: [Bug 6403] Enumeration: define policy > > > > Well, there are certainly semantic differences in several xpath > > operators between 1.0 and 2.0 > > > > On May 12, 2009, at 2:43 PM, Doug Davis wrote: > > > > > > > > I'm not so sure. For example, I'm not an XPath expert but would an > > XPath 2.0 filter dialect need anything more than what's already stated > > for XPath? If not, is it really worth creating a new spec just for a > > QName? > > > > thanks > > -Doug > > ______________________________________________________ > > STSM | Standards Architect | IBM Software Group > > (919) 254-6905 | IBM 444-6905 | _dug@us.ibm.com_ <mailto:dug@us.ibm.com> > > The more I'm around some people, the more I like my dog. > > > > *Geoff Bullen <**_Geoff.Bullen@microsoft.com_* > > <mailto:Geoff.Bullen@microsoft.com>*>* > > > > 05/12/2009 02:19 PM > > > > > > > > > > To > > Doug Davis/Raleigh/IBM@IBMUS, "_public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>" > > <_public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>> > > cc > > > > Subject > > RE: [Bug 6403] Enumeration: define policy > > > > > > > > > > > > > > > > > > > > > > > > > > Hi Doug, > > > > On your first point, > > What seems to be being said here is that if a new YPath filtering > > standard comes along, and someone wants to use it with Enumeration, > > they will have to define the Policy Assertion, and potentially > > standardize it, if interop is an issue. While, with the method > > proposed below, there is an “implied” policy because you can use: > > > > wsen:FilterDialect uri="…/YPath"/> > > > > This seems like a very dangerous assumption, in that there is no real > > definition for what is meant by using YPath as a filter dialect in > > Enumeration – it is just “assumed” to work the “way you think it > > should work”. It seems that is would not be too hard to find examples > > of where two different implementations of the same filtering mechanism > > would produce different results under such circumstances. It would be > > much safer to actually define (somewhere) what the interaction is > > between YPath and Enumeration and in the same place define the policy > > assertion associated with it. Note that the YPath policy assertion > > could have extra extension attributes, where as the method below does > > not allow that (where would they be defined?). > > > > > > On your second point, > > This also ignores the possibility of extension attributes on policy > > assertions – all policy assertions would have to look and behave the > > same in order for the user interface to behave in such a generalized > > manner. Do you really think that users are going to type in raw filter > > expressions, possibly in XML, with no syntax checking on the client > > side? Is this a real use case? > > > > --Geoff * > > > > From:* _public-ws-resource-access-request@w3.org_ > > <mailto:public-ws-resource-access-request@w3.org> > > [_mailto:public-ws-resource-access-request@w3.org_] *On Behalf Of > > *Doug Davis* > > Sent:* Tuesday, May 12, 2009 9:37 AM* > > To:* _public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>* > > Subject:* RE: [Bug 6403] Enumeration: define policy > > > > > > Hi Geoff, > > This is actually really close to my proposal - it just changes the NS > > and localName of the QName - however, there are a couple of aspects of > > this solution that prevented me from picking this approach in my > > original proposal. > > > > First, this will probably require the definition of a 3rd spec for > > each filter dialect. Let's take the case of XPath. Let's assume that > > WS-Enumeration were already completed and behind us (and XPath wasn't > > known, as filter, at that time). If someone wanted to use XPath (which > > has no knowledge of WS-Enum) with WS-Enum, then they would need to > > define (and standardize) this new QName. This would require a new spec > > and its not clear to me who would take on this responsibility. If it > > didn't come through some org, like w3c, then do we run the risk of > > each domain creating their own QName for the same dialect? This could > > hurt interop, cause confusion and cause us more work. > > > > Second, I'm wondering if we lose the ability for smart clients to be > > more dynamic because this requires the client to know about all QNames > > in advance. When parsing the Policy the client would need to know > > which QNames were Filter dialects and which were "something else" > > (which btw it can ignore based on the wsp:Optional attribute). So, if > > the client wanted to present the user with a drop-down box and a list > > of filter dialects to choose from, they could only do it for Filters > > dialects that were hard coded into the system. Without some way to > > know that some new QName were a Filter dialect, they would be a bit > > stuck. In cases where the client system itself will need to act on > > these QNames I think its fair to assume that the client must know > > about each one - however, with Filter dialects the client doesn't > > actually need to act on them. Its the service that does all of the > > work. So, in a dynamic environment (like the drop-down case I > > mentioned above) its possible to prompt the user with a list of Filter > > dialect and an entry field (where they can type the expression) and > > the subscriber's client code never actually needs to know anything > > about the Dialect. > > > > This is why ideally I really wanted something like: > > <wsen:FilterDialect uri="...."/> > > But of course this would require domain specific policy processing - > > which I don't think anyone wants. :-) > > > > I think the mechanism in my proposal, while a bit unique, does provide > > the same functionality of your proposal but also covers the concerns I > > mentioned above. > > And, it shouldn't cost anything more w.r.t. code since in your > > proposal you're asking the client to know about the QNames in advance, > > and there's no reason why they couldn't know about the QNames using > > the form I proposed. It just saves the trouble of having to create a > > new (3rd) spec to link WS-Enum with some expression language. > > > > thanks > > -Doug > > ______________________________________________________ > > STSM | Standards Architect | IBM Software Group > > (919) 254-6905 | IBM 444-6905 | _dug@us.ibm.com_ <mailto:dug@us.ibm.com> > > The more I'm around some people, the more I like my dog. > > > > *Geoff Bullen <**_Geoff.Bullen@microsoft.com_* > > <mailto:Geoff.Bullen@microsoft.com>*>* > > > > 05/12/2009 11:51 AM > > > > > > > > > > To > > Doug Davis/Raleigh/IBM@IBMUS > > cc > > "_public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>" > > <_public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>>, > > "_public-ws-resource-access-request@w3.org_ > > <mailto:public-ws-resource-access-request@w3.org>" > > <_public-ws-resource-access-request@w3.org_ > > <mailto:public-ws-resource-access-request@w3.org>> > > Subject > > RE: [Bug 6403] Enumeration: define policy > > > > > > > > > > > > > > > > > > > > > > > > > > > > We propose the following as clarifying amendments to Doug’s proposal > > for Issue 6403: > > --Geoff * > > The Policy assertion for the XPath filter dialect* * > > > > <wsen:XPathFilterDialect **wsp:Optional?** />* * > > > > /wsen:XPathFilterDialect* > > The policy assertion represents a requirement to include an XPath > > filter in the WS-Enumeration implementation found at this end point > > and, specifically, that the attribute: > > *[Body]/wsen:Enumerate/wsen:Filter/@Dialect="**_ > > http://www.w3.org/TR/1999/REC-xpath-19991116 _* > > <http://www.w3.org/TR/1999/REC-xpath-19991116>*"* MUST be specified in > > wsen:Enumerate messages sent to this Web Service. * > > > > /wsen:XpathFilterDialect/@wsp:Optional="true" * > > > > Per Web Services Policy _[WS-Policy]_ > > <http://www.w3.org/TR/soap12-mtom-policy/#WS-Policy>, this is compact > > notation for two policy alternatives, one with and one without the > > assertion. This indicates that the behavior indicated by the assertion > > is optional, specifically that a message without an filter dialect is > > also supported by the endpoint. * > > /wsen:XPathFilterDialect/@any* > > This is an extensibility mechanism to allow additional attributes to > > be added to the element. > > > > The XPathFilterDialect policy assertion element information item MUST > > NOT include the wsp:Ignorable attribute in its [attributes] property. > > A policy expression containing the XPathFilterDialect policy assertion > > MUST, if present be attached to either a wsdl:binding/wsdl11:binding > > or wsdl:endpoint/wsdl11:port. * > > The normative outline for the Enumeration assertion would be:* > > <wsen:WSEnumeration [wsp:Optional="true"]? ...> > > <wsp:Policy> > > <wsen:XPathFilterDialect [wsp:Optional="true"]? /> > > ... > > </wsp:Policy> > > </wsen:WSEnumeration> > > * > > > > > > From:* _public-ws-resource-access-request@w3.org_ > > <mailto:public-ws-resource-access-request@w3.org> > > [_mailto:public-ws-resource-access-request@w3.org_] *On Behalf Of > > *Doug Davis* > > Sent:* Monday, April 27, 2009 10:07 AM* > > To:* Geoff Bullen* > > Cc:* _public-ws-resource-access@w3.org_ > > <mailto:public-ws-resource-access@w3.org>; > > _public-ws-resource-access-request@w3.org_ > > <mailto:public-ws-resource-access-request@w3.org>* > > Subject:* RE: [Bug 6403] Enumeration: define policy > > > > > > Geoff wrote: > > > In general, we are OK with your proposal for Issue 6403. Here are > > > our general comments on the proposal. I will be happy to provide > > > more concrete suggestions in a subsequent email as we are heads-down > > > processing multiple WS-RA issues at the moment. > > > > > > > > > A) The <x:FilterDialect> is not a concrete policy assertion but a > > > template. This is the first of a kind. How can the WS-RA WG provide > > > an XML Schema definition to specify the syntax of the assertion? > > > Why not just define a policy assertion for the XPath filter dialect? > > > > Can you give an example of what you're thinking of? I think its important > > to do the policy matching w/o needing domain specific code so I'd be > > curious to see what you have in mind. > > > > > We do not understand what is the justification of the statement: > > > "the namespace of this element is application defined, but the > > > Local Name MUST be "FilterDialect"" > > > Why is element matching not using namespaces here? > > > > It _does_ use element matching - so I'm not following. > > > > > >/wsenp:WSEnumeration/wsp:Policy/x:FilterDialect@wsp:Optional > > > This attribute specifies that the assertion is optional per WS- > > > Policy. This attribute MUST be present > > > > > > B) The proposal mandates the use of wsp:Optional attribute. But > > > the minimum here would be to allow the use of the attribute and > > > defer the usage of it to service providers. > > > > We can change this, but my thinking was that the use of the Filter > > element and any particular filter dialect (even if just one is > > supported) is optional for the client. But we can change this > > if people want and assume people are going to be smart enough > > to know that they should really include it - esp. when they support > > more than one dialect. > > > > > C) Would it be useful to check if the proposed assertion follows > > > the best practices outlined in the 'Web Services Policy 1.5 - > > > Guidelines for Policy Assertion Authors' doc [1]. > > > > > > At a glance, it appears that the proposal does not follow best > > > practices 6, 8, 9, 15, 20, 29 and 31. > > > > Feel free to do so, but the only one that seems interesting is > > 29 and I think I got that covered, but we can use more WSDL-specific > > wording if needed. > > > > > --Geoff > > > > > > > > > [1] _http://www.w3.org/TR/2007/NOTE-ws-policy-_ > > > guidelines-20071112/#best-practices-list > > > > > > > > > -----Original Message----- > > > From: _public-ws-resource-access-notifications-request@w3.org_ > > <mailto:public-ws-resource-access-notifications-request@w3.org> > > > [_mailto:public-ws-resource-access-notifications-request@w3.org_] On > > > Behalf Of _bugzilla@wiggum.w3.org_ <mailto:bugzilla@wiggum.w3.org> > > > Sent: Tuesday, April 21, 2009 1:39 PM > > > To: _public-ws-resource-access-notifications@w3.org_ > > <mailto:public-ws-resource-access-notifications@w3.org> > > > Subject: [Bug 6403] Enumeration: define policy > > > > > > _http://www.w3.org/Bugs/Public/show_bug.cgi?id=6403_ > > > > > > > > > > > > > > > > > > --- Comment #4 from Robert Freund <_bob@freunds.com_ > > <mailto:bob@freunds.com>> 2009-04-21 20:38:56 --- > > > modified proposal as above with the following: > > > > > > insert after :/wsenp:WSEnumeration/wsp:Policy/x:FilterDialect > > > An endpoint should include a filterdialect policy assertion for each > > of the > > > filter dialects that it supports. > > > > > > > > > -- > > > Configure bugmail: > > _http://www.w3.org/Bugs/Public/userprefs.cgi?tab=email_ > > > ------- You are receiving this mail because: ------- > > > You are the QA contact for the bug. > > > > > > > > > > > >
Received on Thursday, 14 May 2009 23:01:26 UTC