Re: (FC-Devel) Update

[Jeff Wolfe <jwolfe@felgroup.creol.ucf.edu>]

Hello Andrey,

Andrey V Khavryutchenko wrote:
> I've just updated my pages at http://www.freecase.seul.org/~akhavr with
> changes that should be there already few weeks ago.  Sorry for delay.

I added a link to this site from the freecase details page. 
If you could add a link back to the project, I think it
would be helpful.  With a persistent link, maybe more people
will see them and comment.
 
> >From the architectual viewpoint, the repository breaks nicely in tree
> packages:
>   a. the UML package, that provides the client functionality
>   b. the persistence package, that stores the UML data in a storage
>   c. the CM package, that deals with checkouts, updates, commits, etc.

I just want to clarify my understanding.  For (a), are you
referring to the interface provided to the client to access
the information?  Several people have suggested that we use
an architecture that will support other modeling languages
in the future.  Would it be better to provide a more general
meta-model interface, and force the client software to turn
this into UML?  Perhaps we could have a meta-model interface
and then allow server-side plug ins for UML and future
models.  These plug ins could act mostly like a translator. 
As in all client server systems, we need to strike the
proper balance between work done by the client and work done
by the server.

Then, (b) could focus strictly on storing the meta-model and
would be isolated from all other details.  Now for another
question, if the repository stores model information, where
and how do we store document info?  I'm talking about things
like page layout, how to display class detail (folded,
unfolded), etc.  It is my opinion that the model should be
separated from the presentation documents, but also that the
model should reflect the current contents of the documents. 
Does this make sense?

Finally, for (c), we have discussed using cvs.  This is
certainly a good move.  Why should we also try to create a
revisioning tool?  However, we need to make sure that we
don't create a document format that gets corrupted easily. 
Interesting things can happen when dealing with versioning. 
Can someone shed some light on whether or not this is likely
to be a problem?


> I'd like to see model data to be stored in the sgml (or xml) files.  To do
> that we need two things:
>   (1) The program interface to the sgml data
>   (2) The document type definition for UML model data

Personally, I am uneducated on the topic of SGML.  However,
I have heard from reliable sources that this is likely to be
a very good move.  A friend who works in document conversion
tells me that it is very easy to deal with data stored in
this format.  I'll do more personal reading, but support
this notion now.

---Time has passed, and it's now 1 hour later...
I just went off and looked at the CDIF site, www.cdif.org. 
There is really a lot of interesting stuff there.  It looks
like they have done a great deal of work that might be very
helpful to us in these early stages.  It would be best if we
could align ourselves with whatever common approach modern
CASE tools are going to use for interoperability.  CDIF
seems like a major player.  The only major problem I see is
that the actual specifications are not free.  Is this really
a problem?  I don't think so.  There is a lot of free
information on their site.  Perhaps someone on the list who
is more actively involved with commercial CASE development
could let us know what the corporate perspective is
regarding interoperability.

I now think that we might be best off to implement a
repository based on their meta-meta-model concept.  In
particular, take a look at 'Johannes Ernst: How to use the
CDIF Transfer Format with the UML Meta-model' located at
http://www.cdif.org/workingpapers/misc/index.html.  I
haven't read it completely, but it looks interesting.  I
think this would only impact us in (b) above and (2) above.

I am now very interested in CDIF and would request you, the
freecase community, to comment on this.  If necessary, we
can pursue getting some actual specifications through
donations etc.  

Now that I am excited, it must be time for someone to come
burst my bubble :)

Best regards,
Jeff Wolfe

PS  I'll be unavailable next week from 11/2 to 11/8.  During
that time, I won't have access to email, but will respond to
comments when I return.