[oslc-core] programmatic selection of creation factories

Tue Jun 1 14:14:08 EDT 2010

Dave,

I don't understand your statement: "Also, a Resource Shapes does not 
indicate which type it describes."

The spec has a property on Resource Shape, oslc:describes, that identifies 
the rdf:type of the resource [1]. It seems the text has been edited, but 
the diagram shows it, and it is present in the examples [2]

Here's an excerpt from the example which you wrote I believe:

<oslc:Shape
   rdf:about="http://example.com/shapes/commentshape"
   xmlns:oslc="http://open-services.net/xmlns/oslc-core#" 
   xmlns:oslc_blog="http://open-services.net/xmlns/oslc-core/bogus/blogs#" 

   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   xmlns:foaf="http://http://xmlns.com/foaf/0.1/"
   xmlns:dc="http://purl.org/dc/elements/1.1/">

     <dc:title>Blog Comment Shape</dc:title>
     <rdf:type rdf:resource="http://open-services.net/xmlns/oslc#Shape" />

     <oslc:name>Comment</oslc:name>
     <oslc:describes rdf:resource="
http://open-services.net/xmlns/bogus/blog#Comment" />

[1] 
http://open-services.net/bin/view/Main/OSLCCoreSpecAppendixADRAFT#oslc_ResourceShape_Resource
[2] 
http://open-services.net/bin/view/Main/OSLCCoreSpecAppendixBDRAFT#Shape_Resources

Regards, 
___________________________________________________________________________ 

Arthur Ryman, PhD, DE

Chief Architect, Project and Portfolio Management

IBM Software, Rational

Markham, ON, Canada | Office: 905-413-3077, Cell: 416-939-5063
Twitter | Facebook | YouTube

From:
Dave <snoopdave at gmail.com>
To:
Arthur Ryman/Toronto/IBM at IBMCA
Cc:
Jim des Rivieres/Ottawa/IBM at IBMCA, oslc-core at open-services.net, David M 
Johnson <dmjohnso at us.ibm.com>, John Wiegand <John_Wiegand at us.ibm.com>, 
oslc-core-bounces at open-services.net
Date:
06/01/2010 01:09 PM
Subject:
Re: [oslc-core] programmatic selection of creation factories

On Mon, May 31, 2010 at 10:21 AM, Arthur Ryman <ryman at ca.ibm.com> wrote:
> A creation factory has a link to a shape (oslc:shape) resource that
> descibes that resources it creates, e.g. blog entry versus blog comment.
> Isn't that enough to identify the purpose of the creation factory?

There was an error in the spec that I just corrected. We were saying
that a CreationFactory MUST provide exactly-one Resource Shape. That
is wrong. Resource Shapes are supposed to be optional and a creation
factory can support multiple resource types and shapes.

Current spec text says that: a Creation Factory MAY provide Resource
Shapes that describe the shape of resources that may be created. So,
shape is optional and there may be more than one.

Also, a Resource Shapes does not indicate which type it describes. So,
Ian is right -- we have not tied shapes to types yet.

Currently, there is no reliable way to select the creation factory or
query capability to be used to query for a given resource type. That
seems like a problem to me.

Thanks,
- Dave

PS. I've captured this an other recent issues on the issues page and I
will summarize them in the agenda for the WG meeting tomorrow.

   http://open-services.net/bin/view/Main/OslcCoreV1Issues

> From:
> Jim des Rivieres/Ottawa/IBM at IBMCA
> To:
> Scott Bosworth <bosworth at us.ibm.com>, David M Johnson
> <dmjohnso at us.ibm.com>, Steve K Speicher <sspeiche at us.ibm.com>
> Cc:
> oslc-core at open-services.net, John Wiegand <John_Wiegand at us.ibm.com>
> Date:
> 05/31/2010 09:57 AM
> Subject:
> [oslc-core] programmatic selection of creation factories
> Sent by:
> oslc-core-bounces at open-services.net
>
>
>
> ref: http://open-services.net/bin/view/Main/OSLCCoreSpecDRAFT (r95, May
> 27)
>
> Architecturally, it makes sense for a particular Service to have 
multiple
> occurrences of creationFactory. Take the example OSLC Blog Service as a
> concrete instance: Blog Entry and Blog Comment each have a
> creationFactory. The CreationFactory inline local resource carries a
> mandatory dc:title that helps a user in choosing among them. However, I
> don't see anything that would allow a programmatic client to make an
> analogous choice. For instance, if my client needs to create a Blog 
Entry,
>
> how would it discover which creationFactory to use?
>
> In general, OSLC domains must support the needs of programmatic clients 
as
>
> well as ui clients. Adding a mandatory identifier to CreationFactory 
would
>
> do the trick. The identifier could be a URI. Well-known URIs could be
> defined in the OSLC domain spec; i.e., OSLC Blog Service could declare 
the
>
> identifiers "http://open-services.net/bogus/blog/createEntry" and "
> http://open-services.net/bogus/blog/createComment" for distinguishing 
its
> primary creation factories. All clients would be told to tolerate and
> ignore entries with identifiers that they do not recognize; this allows
> new identifiers can be introduced at any time without affecting
> programmatic clients. And the mechanism can be opened up to individual
> providers by allowing a provider to define additional provider-specific
> identifiers.
>
> I would make the exact same argument for queryCapability, 
selectionDialog,
>
> and creationDialog as for creationFactory. Any OSLC domain that has
> multiple major resource types might decide to provide separate query
> capabilities, pickers, and creation uis for each type. Adding an
> identifier to QueryCapability and Dialog would address the needs of
> programmatic clients.
>
> Regards,
> Jim
>
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