RE: [uddi-spec] Issue with Value Sets with entity keys as values

["John Colgrave" <colgrave@hursley.ibm.com>]

Sam,

I have prepared a Change Request (CR-032) for this which I will be making
available shortly (as soon as I figure out how to!).

I do not think that the V2 specification needs to change. I am a little
concerned that we still use "checked" to mean both internally verified and
externally verified but I am choosing to ignore that for the moment.  The
tModels for owningBusiness and isReplacedBy are both categorized as checked
in V2, so V2 already has the concept of validating that a keyValue is a
valid entity key, relying on "magic", or at least the words in the V2
specification, to know which type of entity keys are valid.

It is tempting to leave the affected tModels in the WSDL TN as unchecked to
simplify the implementation of the TN but I think that the right thing to do
is to declare them checked.  I have updated the TN accordingly.  It will be
part of a V2 implementation of the WSDL TN to do the validation in the same
way that it is currently done for owningBusiness and isReplacedBy, using the
same amount of "magic" as for owningBusiness and isReplacedBy.

I think this is sufficient for a V2-only implementation of the WSDL TN.

The extra work to map the keys only applies to a multi-version registry.  I
think it is a good idea to remove "magic" where we can so I am still
proposing a new categorization to indicate both that key mapping is required
and also the valid type(s) of entity keys.  I think this is an improvement
on the "magic" in V2.  The V3 versions of the existing V2 tModels and all
the new V3 tModels that take entity keys as values will have this extra
categorization added to them, including the WSDL TN tModels, and this will
allow a multi-version registry implementation to do the appropriate
validation and mapping.

I disagree with a few elements of your recap but I will leave any further
discussion until the CR appears.

John Colgrave
IBM


-----Original Message-----
From: Wai-Kwong Sam LEE [mailto:Sam.Lee@oracle.com] 
Sent: 30 April 2003 23:15
To: John Colgrave
Cc: uddi-spec@lists.oasis-open.org
Subject: Re: [uddi-spec] Issue with Value Sets with entity keys as values

John / Claus / Others,

I think if we go down the path of making the registry do the mapping, UDDIv2

specification may need to be changed as well.

The scenario is, in order to allow the registry do the automatic mapping of
the 
keyValue from v2 keys to v3 keys, the registry needs to know that the
keyValues 
are indeed geniue entity keys, (similar to the case that the registry needs
to 
validate that tModelInstanceInfo/@tModelKey is indeed a real tModelKey).

Currently, these tModels (defined in UDDI-WSDL TN, such as
portTypeReference) 
are unchecked. They need to be made checked so that the registry can reject 
invalid keyedReferences (that do not reference to a real tModelKey).

Making these tModels checked is probably a good feature to begin with. It
can 
reduce the likelihood of poor data and be consistent with the checking
behavior 
of similar canonical tModels like owningBuinsess. But the catch is, we need
to 
start doing it in UDDIv2.


A recap of the discussion so far:

1. owningBussiness_v3 approach
    - a burden to the publishers (or publishing app),
      who have to explicitly publish two keyedReferences: one for v2
      and one for v3.
    - in particular, a burden to publisher during v2-v3 migration
    - inquiry users /apps are not affected, as they know the
version-specific
      keys: both the categorization scheme tModelKey and the value sets are
      version-specific.

2. make registry do the mapping, by categorizing these new tModels
    with an indication that the value set keyspace is UDDI entity keys
    - relieves the burden on publishers in approach 1
    - inquiry users / apps are again not affected, as in approach 1
    - some burden to registry implementation, potentially performance
concern.
    - need to change the v3 spec
    - need to change the v2 spec too, in my opinion.



- sam

John Colgrave wrote:
> Claus,
> 
> I regard the current specification of owningBusiness_v3 etc. to be an
error
> as it has the same problems I described for the new Category Systems in
the
> WSDL TN.
> 
> I quite agree that this will require a change to the V3 specification and
> envisaged turning my e-mail into a Change Request for V3.  I saw this as
> introducing another dependency of the WSDL TN on a V3 CR.
> 
> Given/Assuming that the V3 spec. is in error then I think it is
appropriate
> to change the V3 spec. to add this extra Category System, describe how a
> V2/V3 registry implementation must handle Category Systems that have
entity
> keys as values and remove the V3 versions of any affected Category
Systems.
> 
> As you know, I do not regard this as a significant performance issue as it
> is "just" another instance of multi-version key handling, but triggered by
> categorization rather than static typing.  If people feel that this
feature
> will significantly impact UDDI performance they should certainly say so
but
> I think this feature is something that we have to have to make current V3
> functionality usable, not to mention its critical importance to the way
that
> the WSDL TN would work in a multi-version registry, and so any performance
> concerns would have to be weighed against that.
> 
> John Colgrave
> IBM
> 
> 
> -----Original Message-----
> From: Von Riegen, Claus [mailto:claus.von.riegen@sap.com] 
> Sent: 28 April 2003 08:39
> To: Anne Thomas Manes; uddi-spec@lists.oasis-open.org
> Subject: RE: [uddi-spec] Issue with Value Sets with entity keys as values
> 
> Separate tModels for V2 and V3 are necessary since the V3 specification by
> no means outlines a special handling of uddiKey-based value sets.
> I agree that it would be a good thing to have it - at least for the users
of
> a UDDI registry - but it would require at least
> - a specification of the special behavior for uddiKey-based value sets in
a
> multiversion registry
> - a canonical categorization of such value sets so that both the nodes of
a
> UDDI registry and UDDI users can programmatically discover when such
> behavior is to be applied.
> 
> As a consequence, I don't see a possibility to introduce such a behavior
in
> a Technical Note. It would be possible if we change the V3 specification
> itself accordingly (including the currently built-in behavior for the
> "owningBusiness" and "validatedBy" value sets). However, there are at
least
> two
> issues this approach faces:
> 1) We decided to change the V3 specification for errors, inconsistencies
and
> ambiguities only. The proposed behavior is certainly a new feature. Thus,
we
> must have good reasons to introduce a new feature in a V3 errata.
> 2) While the proposed behavior certainly helps UDDI users, it puts another
> burden on UDDI implementations, at least as far as the performance is
> concerned. I would like to see more feedback from other implementers on
this
> issue.
> 
> Claus
> 
> -----Original Message-----
> From: Anne Thomas Manes [mailto:anne@manes.net] 
> Sent: Mittwoch, 16. April 2003 15:46
> To: uddi-spec@lists.oasis-open.org
> Subject: RE: [uddi-spec] Issue with Value Sets with entity keys as values
> 
> 
> +1.
> 
> Having different tModels for V2 and V3 won't work. The only viable option
is
> to use mapped keys.
> 
> I'm not convinced that we need to create a new categorization, though. I
> think we can get by with a new uddi-type ("entityTypeKeys" similar to
> "checked") - or perhaps a set of types that would allow us to specify the
> type of entity key:
> - entityTypeKeys
> - businessKeys
> - serviceKeys
> - bindingKeys
> - tModelKeys
> 
> Anne
> 
> 
>>-----Original Message-----
>>From: John Colgrave [mailto:colgrave@hursley.ibm.com]
>>Sent: Wednesday, April 16, 2003 5:25 AM
>>To: uddi-spec@lists.oasis-open.org
>>Subject: [uddi-spec] Issue with Value Sets with entity keys as values
>>
>>
>>The WSDL TN makes use of three Category Systems that have entity keys,
>>specifically tModel keys, as the valid values:
>>1) portType tModel reference
>>2) protocol categorization
>>3) transport categorization
>>
>>The valid values of these Category Systems are, deliberately, dynamic and
>>depend on the registry content at the time that an entity is
>>published that
>>uses one of these Category Systems.  The valid values also depend on which
>>version of the UDDI API is being used.  If a keyedReference is being
>>published using V2 then the valid values are the set of V2 entity keys,
>>perhaps of one particular type such as tModel keys.  If a
>>keyedReference is
>>being published using V3 then the valid values are the
>>corresponding set of
>>V3 keys.  The valid UDDI entities are the same in each case, but
>>the type of
>>key that is used to refer to them is appropriate to the version
>>of the UDDI
>>API being used.
>>
>>These Category Systems are not compatible with the support for External
>>Checked Value Sets.
>>
>>The WSDL TN was written (implicitly) assuming that the keyValue in
>>keyedReferences for these Category Systems would be mapped
>>between V1/V2 and
>>V3 in the same way that entity keys are mapped between versions everywhere
>>else they are used.
>>
>>As an example, if a V2 application wanted to publish a binding
>>tModel for a
>>wsdl:binding that used the SMTP transport it would use the following
>>keyedReference:
>>
>><keyedReference tModelKey="uuid:4eeccd58-d3b0-3a6f-a466-9cce01cb1273"
>>keyName="V2 transport"
>>keyValue="uuid:93335D49-3EFB-48A0-ACEA-EA102B60DDC6"/>
>>
>>If, on the other hand, it were a V3 application that wanted to publish the
>>same binding tModel, it would use the following keyedReference:
>>
>><keyedReference tModelKey="uddi:uddi.org:wsdl:categorization:transport"
>>keyName="V3 transport" keyValue="uddi:uddi.org:transport:smtp"/>
>>
>>So far, so good.
>>
>>The issue is what happens when a V3 application retrieves a binding tModel
>>that was published by a V2 application, or vice versa.  The WSDL
>>TN assumes
>>that both the tModelKey value and the keyValue are mapped as
>>appropriate so
>>that the application that retrieves the tModel sees exactly the same
>>keyedReference whether the keyedReference was saved by a V2
>>application or a
>>V3 application.
>>
>>This would appear to me to be a good thing.
>>
>>The suggestion made by Claus is to have separate V3-specific Category
>>Systems that can only have V3 keys as their valid values, and have the
>>original Category Systems only have V2 keys as their valid
>>values.  This is
>>similar to what was done with owningBusiness in V3.
>>
>>Note that both the "V2" and "V3" Category Systems would have both
>>V2 and V3
>>keys so they could each be used by both versions of the UDDI API but the
>>application would have to know both the V2 key for an entity and the
>>corresponding V3 key for an entity, and both V2 and V3 applications would
>>have to be written to know about both versions, which is a significant
>>difference.
>>
>>If an application were not written with knowledge of both
>>versions then if a
>>V2 application published the binding tModel as above and a V3 application
>>were to retrieve it, the V3 application would see a single keyedReference
>>with a tModelKey that was the V3 key of the V2 Category System and a
>>keyValue that was the V2 key of a protocol tModel.  This V2 key would be
>>meaningless to the V3 application.
>>
>>Conversely, if a V3 application published the binding tModel and then a V2
>>application retrieved it, it would see a single keyedReference with a
>>tModelKey that was the V2 key of the V3 Category System, which it
>>would not
>>recognize as the V2 application was written without knowledge of V3, and a
>>keyValue that was the V3 key of a protocol tModel.  This V3 key would be
>>meaningless to the V2 application.
>>
>>The only way that I can see the "owningBusiness" approach working
>>is if the
>>applications take responsibility for dealing with the
>>multi-version issues.
>>
>>To continue the example, this would mean that an application that
>>published
>>a binding tModel would have to be aware of both the V2 Category System and
>>the V3 Category System and publish two keyedReferences, one in each of the
>>Category Systems so that the binding tModel could be used by both
>>V2 and V3
>>code.  I do not know how it is intended that V2 code can find the V3 key
>>corresponding to a V2 key or vice versa.
>>
>>Assuming that the binding tModel were published with both keyedReferences,
>>then the code that retrieved the tModel would have to ignore one of the
>>keyedReferences (the one using the "foreign" version) and use the one that
>>matched its version of the UDDI API.
>>
>>There would be a migration issue as well as if the tModels were originally
>>published in a V2-only registry then there is no way that the V3-specific
>>keyedReference could be published, so when the registry were upgraded to
>>support both V2 and V3, the extra keyedReferences would have to
>>be added to
>>each tModel before they could be used by V3 applications.
>>
>>I just can't see how to make this approach work, and that applies
>>to things
>>like owningBusiness that are already in V3 as much as the WSDL TN.
>>
>>The only way that I can see to allow for Category Systems, or
>>Value Sets in
>>general, that can take entity keys as values is to apply the
>>mapping to the
>>entity keys that are used in the keyValue attribute in the same
>>way that we
>>map entity keys everywhere else.  This is the only way that I can see to
>>allow both V2 code and V3 code to know about only their own version of
>>entity keys and have interoperability/portability of registry content
>>across/between applications written to different versions of the UDDI API
>>that access the same registry.
>>
>>As Tony pointed out, probably the best way to achieve this is to
>>categorise
>>such Value Sets with an indication that the valid values are UDDI entity
>>keys, and the specific type of entity if that is known, as it is
>>in the case
>>of the WSDL TN.
>>
>>Such a categorization would have to be done via a new canonical
>>tModel that
>>was added to V3, and the new Category Systems etc. such as
>>owningBusiness_v3
>>would have to be removed from V3.
>>
>>John Colgrave
>>IBM
>>
>>
>>
> 
>