[OSLC-RM] Link types
Torge Kummerow
torgato at gmx.de
Wed Oct 7 08:54:24 EDT 2009
Well, if it should be part of V1.0 or not is not my decision to make,
however I would say this is an inevitable future for LinkTypes. To be
able to constrain them to a specific source and target element group.
Especially if we introduce a catalog of LinkTypes this would act as a
good filter, showing only matching Types. However I doubt that a
granularity beyond the domain is of much use. But this depends on the
number of distinguishable sub elements in each domain I guess.
Torge.
James Conallen schrieb:
> I too think that we need to accept for the fact that now each group will
> have its own solution, (which are somewhat similar when you consider the
> potential). I also think that no matter what is done, clients will have
> to change in the future, so why not do something now to support the
> essential use cases and get us all started.
>
> In your second point, you describe a potential property of a link type
> definition. The ability for a specific link type to restrict what can be
> on either end based on the 'domain' of the resource, or maybe even the
> specific type of resource. I worry about getting this aspect of link
> definition right so early on. While I think a generic and flexible link
> management system can be defined for 1.0, I think this particular aspect
> of a link type's definition might not be necessary or 1.0.
>
> <jim/>
>
> jim conallen
> jconallen at us.ibm.com
> Rational Software, IBM Software Group
>
>
>
> Inactive hide details for Torge Kummerow ---10/07/2009 08:21:40
> AM---Well, it can?t hurt, if each group is presenting a solutioTorge
> Kummerow ---10/07/2009 08:21:40 AM---Well, it can?t hurt, if each group
> is presenting a solution it thinks is the best approach. The con
>
>
> From:
> Torge Kummerow <torgato at gmx.de>
>
> To:
> oslc-rm at open-services.net
>
> Date:
> 10/07/2009 08:21 AM
>
> Subject:
> Re: [OSLC-RM] Link types
>
> Sent by:
> oslc-rm-bounces at open-services.net
>
> ------------------------------------------------------------------------
>
>
> ic
> Well, it can?t hurt, if each group is presenting a solution it thinks is
> the best approach. The consolidation will have to take place IHMO and
> then as lots of input for finding the best solution.
>
> I also think that not only the linking spec should be defined globally,
> but also the mechanism in doing so shouldn't care which objects are
> being linked right now, only the LinkTypes should care. (An RM->RM
> LinkType can?t link a QM object with an CM object for example)
>
> Greetings,
> Torge
>
> James Conallen schrieb:
> > I absolutely agree. A uniform linking approach is critical to cross
> > domain collaboration.
> >
> > The problem is that most of the new OSLC workgroups are on the hook to
> > provide a 1.0 specification by the end of this calendar year. The
> > governing philosophy of the OSLC has been to deliver small sets of
> > specifications that provide value immediately, and that can be built on
> > later.
> >
> > With that said we can either skip any attempt to define how links can be
> > managed, since it will most likely change once things are consolidated
> > later (the OSLC is working on providing common specifications across all
> > domains). Or we can provide something that is useable now, but will most
> > likely have to be changed later.
> >
> > If we don't do anything now, the spec will be incomplete with respect to
> > the essential use cases, since it will require additional knowledge of
> > the implementing system to be able to manage links, and that is
> > essentially another form of point-to-point integration that we see
> > across the tools today. If we do specify either a flexible approach, or
> > just define a fixed set of what we consider common link types, then
> > clients built to this spec will have to change (possibly losing
> > functionality) when the later ones come out.
> >
> > <jim/>
> >
> > jim conallen
> > jconallen at us.ibm.com
> > Rational Software, IBM Software Group
> >
> >
> >
> > Inactive hide details for "Simon Wills" ---10/07/2009 07:47:09
> > AM---Hi"Simon Wills" ---10/07/2009 07:47:09 AM---Hi
> >
> >
> > From:
> > "Simon Wills" <simon.wills at integrate.biz>
> >
> > To:
> > "Ian Green1" <ian.green at uk.ibm.com>, James
> Conallen/Philadelphia/IBM at IBMUS
> >
> > Cc:
> > <oslc-rm at open-services.net>
> >
> > Date:
> > 10/07/2009 07:47 AM
> >
> > Subject:
> > RE: [OSLC-RM] Link types
> >
> > ------------------------------------------------------------------------
> >
> >
> >
> > Hi
> >
> > I think that there are three distinct issues here, namely:
> >
> > a. Whether there is a need for a uniform approach to
> > defining link-related resources across OSLC;
> > b. Whether we attempt to define a minimal set of
> > standardised link types;
> > c. Assuming that we **do** adopt a uniform approach to
> > linking across OSLC, how and when we do so.
> >
> > Of these points, deciding whether or not to implement a uniform linking
> > model is by far and away the most important. Standardising link labels
> > is a 'nice to have' that follows on from this first decision (this was
> > the main focus of the RM discussion document), but is something that we
> > can live without. And the last point is to do with implementation.
> >
> > Ben's interests (i.e. reporting) provide a good illustration of the key
> > issue. If I understand correctly, he wants to be able to generate
> > reports about lifecycle artefacts, some of which may require him to
> > traverse links between artefacts, without having to make allowances for
> > the domains in which those artefacts live. This seems to me to be
> > entirely reasonable -- and reporting isn't the only domain for which
> this
> > expectation holds.
> >
> > OSLC stands for Open Services for Lifecycle Collaboration. Lifecycle
> > collaboration requires that we leverage relationships between lifecycle
> > artefacts. If we don't tackle the issue of uniformity in the handling
> > of links, we risk ending up with a series of poorly connected domain
> > islands, each with its own domain-specific linking paradigm. Surely
> > there is a /prima facie/ case to recognise that links are the things
> > that tie these domains together, and hence that the definition of
> > link-related resources and their behaviour should be common across all
> > OSLC domains?
> >
> > Best regards
> >
> > Simon
> >
> > *From:* oslc-rm-bounces at open-services.net
> > [mailto:oslc-rm-bounces at open-services.net] *On Behalf Of *Ian Green1*
> > Sent:* 07 October 2009 11:39*
> > To:* James Conallen*
> > Cc:* oslc-rm at open-services.net*
> > Subject:* Re: [OSLC-RM] Link types
> >
> >
> > Hello Jim,
> >
> > I think your description of how OSLC links currently work in the
> > defining of a relationship is accurate. There has been some discussion
> > about the merit of such a design, since it is exposed to a fragility,
> > namely, that for each link, there should be a corresponding link in the
> > other direction. The need for the "backlink" as it has been called, aids
> > navigability (we typically want the relationship to be navigable in both
> > directions). It is also reasonably easy to implement.
> >
> > The fragility is maintaining this invariant: for example, when a
> > resource is deleted, any "backlinks" to that resource should be removed.
> > There are other "relationship management" designs which don't have this
> > weakness.
> >
> > My reading of Simon's document is that it is talking about these
> > relationships, rather than the lower-level "nuts and bolts" of how one
> > resource links to some other resource. We need to think about how we can
> > uniformly manage these relationships across all the domains.
> >
> > best wishes,
> > -ian
> >
> > ian.green at uk.ibm.com (Ian Green1/UK/IBM at IBMGB)
> > Chief Software Architect, Requirements Definition and Management
> > IBM Rational
> >
> > From: James Conallen <jconallen at us.ibm.com>
> > To: Benjamin Williams/UK/IBM at IBMGB
> > Cc: Ian Green1/UK/IBM at IBMGB, oslc-rm at open-services.net
> > Date: 06/10/2009 16:44
> > Subject: Re: [OSLC-RM] Link types
> >
> > ------------------------------------------------------------------------
> >
> >
> >
> > I have one concern about the link types document's attempt to define
> > *both* the forward and reverse links. I believe that the general OSLC
> > mechanism for creating bi-directional links is to create two
> > unidirectional links managed by each server, and hope that it is
> > possible with a query on the other server to find the right back link
> > when deleting.
> >
> > If this is the case, then we should probably restrict the definition of
> > the link types to those that are managed by the OSLC RM implementing
> > service, and not make assumptions that all the other services (i.e. OSLC
> > CM, OSLC AM, OSLC QM, ...) will support these OSLC RM defined link types.
> >
> > In the OSLC AM space our scenarios have all sorts of link types that are
> > referenced. For example a model element can implement a requirement, or
> > specify a requirement, or a requirement resource can be documentation
> > (i.e. how to guide) for a model element. Given that both models and
> > requirements can be used in many different ways, it is hard to pin down,
> > generically, just a few relationship types between AM resources and
> > requirements. With this said, if we just say that links from
> > Requirements to Architecture Management Resources will be one of
> > (modeledBy, realisedBy or incorporatedBy) that will be fine from an OSLC
> > AM client point of view.
> >
> > <jim/>
> >
> > jim conallen
> > jconallen at us.ibm.com
> > Rational Software, IBM Software Group
> >
> >
> >
> > Inactive hide details for Benjamin Williams ---10/06/2009 10:22:09
> > AM---Ian As per my other email on reporting, I feel that sucBenjamin
> > Williams ---10/06/2009 10:22:09 AM---Ian As per my other email on
> > reporting, I feel that such such collaboration
> >
> >
> > From:
> > Benjamin Williams <bwilliams at uk.ibm.com>
> >
> > To:
> > Ian Green1 <ian.green at uk.ibm.com>
> >
> > Cc:
> > oslc-rm at open-services.net, oslc-rm-bounces at open-services.net
> >
> > Date:
> > 10/06/2009 10:22 AM
> >
> > Subject:
> > Re: [OSLC-RM] Link types
> >
> > Sent by:
> > oslc-rm-bounces at open-services.net
> >
> > ------------------------------------------------------------------------
> >
> >
> >
> > Ian
> >
> > As per my other email on reporting, I feel that such such collaboration
> > and consistency across domains will be extremely important, if not
> > absolutely necessary.
> > Specifically in the context of reporting, the features exposed by
> > service providers across each domain will need to (consistently) support
> > the requirements and use-cases defined in the Reporting domain such that
> > reporting consumers can leverage lifecycle data without needing any
> > knowledge of the source domains and any differences in the way they
> > expose data.
> >
> > The scenarios and use-cases that we are defining in the reporting domain
> > should be entirely domain agnostic, as far as I am concerned. We can use
> > specific examples for both single domain reporting as well as cross
> > domain reporting, but the domains used in the examples should be freely
> > interchangeable without any impact on the reporting consumer.
> >
> > The reporting domain is still in its infancy, and my involvement in OSLC
> > is only just beginning, but from what I understand, the reporting domain
> > might be one of the first things to force us to think about some of the
> > cross domain issues that you and Simon have discussed.
> >
> > /Ben
> >
> >
> -----------------------------------------------------------------------------
> > Benjamin Williams
> > Senior Product Manager - Rational Publishing Engine
> >
> > Email: bwilliams at uk.ibm.com
> > Tel: +44 20 8818 4360
> > Cell: +44 7710 637 067
> > IBM Extension: 364360
> > IBM ITN: 37364360
> >
> -----------------------------------------------------------------------------
>
> >
> >
> > From: Ian Green1/UK/IBM at IBMGB
> > To: "Simon Wills" <simon.wills at integrate.biz>
> > Cc: oslc-rm at open-services.net
> > Date: 06/10/2009 14:16
> > Subject: Re: [OSLC-RM] Link types
> > Sent by: oslc-rm-bounces at open-services.net
> >
> > ------------------------------------------------------------------------
> >
> >
> >
> >
> > Hello Simon,
> >
> > this is good progress both on explaining our current position w.r.t.
> > link types, and also taking a longer term view of the role we see link
> > types playing the future. Thanks very much for putting this together.
> >
> > Steve/Scott: whilst there is no pressure as yet to drive this forward,
> > Simon makes a good case for any such effort to be cross-OSLC domains.
> > How do you see this shaping up over time? Is there some tension between
> > designing an OSLC-wide vocabulary and being entirely scenario-driven?
> >
> > best wishes,
> > -ian
> >
> > ian.green at uk.ibm.com (Ian Green1/UK/IBM at IBMGB)
> > Chief Software Architect, Requirements Definition and Management
> > IBM Rational
> >
> > From: "Simon Wills" <simon.wills at integrate.biz>
> > To: Ian Green1/UK/IBM at IBMGB
> > Date: 05/10/2009 15:42
> > Subject: Link types
> >
> >
> > ------------------------------------------------------------------------
> >
> >
> >
> > Hi Ian
> >
> > Just to let you know ... I've put a new section titled 'Discussion
> > Topics' in the right hand sidebar of the main RM page, and put a link to
> > a discussion document on link types (at
> > _http://open-services.net/bin/view/Main/RmDiscussionLinkTypes_). Haven't
> > quite sussed out how to format tables properly in the Wiki editor, but
> > the content is all there.
> >
> > Would you like me to put out an announcement on the mailing list?
> >
> > Cheers
> >
> > Simon
> >
> > ------------------------------------------------------------------------
> >
> > Simon Wills
> > Managing Director *
> > integrate systems engineering ltd*
> > m: +44 (0)7967 091824
> > t: +44 (0)1225 859991
> > f: +44 (0)1225 859993
> > e: simon.wills at integrate.biz
> > w: _www.integrate.biz_ <http://www.integrate.biz/>
> > ------------------------------------------------------------------------
> >
> >
> >
> >
> > ------------------------------------------------------------------------
> >
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