[OSLC-RM] Link types

Ian Green1 ian.green at uk.ibm.com
Wed Oct 7 06:39:30 EDT 2009 

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



Benjamin 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 







Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU 





_______________________________________________
OSLC-RM mailing list
OSLC-RM at open-services.net
http://open-services.net/mailman/listinfo/oslc-rm_open-services.net





Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU 





_______________________________________________
OSLC-RM mailing list
OSLC-RM at open-services.net
http://open-services.net/mailman/listinfo/oslc-rm_open-services.net







Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU






-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0003.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 105 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0001.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0002.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0003.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0004.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0005.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0006.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0007.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0008.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0009.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0010.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0011.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/gif
Size: 45 bytes
Desc: not available
URL: <http://open-services.net/pipermail/oslc-rm_open-services.net/attachments/20091007/577d2f04/attachment-0012.gif>

More information about the Oslc-Rm mailing list