On Sat, Apr 11, 2015 at 12:39 PM, Peter Ansell <ansell.pe...@gmail.com>
wrote:
> On 11 April 2015 at 22:11, Reto Gmür <r...@apache.org> wrote:
> > On Mon, Mar 30, 2015 at 2:07 PM, Benedikt Ritter <brit...@apache.org>
> wrote:
> >
> >> Hello Reto,
> >>
> >> 2015-03-30 14:45 GMT+02:00 Reto Gmür <r...@apache.org>:
> >>
> >> > Hi all,
> >> >
> >> > The clerezza commons RDF proposal that was in the sandbox and is now
> in
> >> the
> >> > clerezza-rdf-core repository has been changed to use
> >> > org.apache.clerezza.commons-rdf.
> >> >
> >> > As you know if all goes well clerezza will be based in the result of
> the
> >> > incubating project. If however this project should unfortunately not
> lead
> >> > to something generic enough to be used for interfacing arbitrary data
> as
> >> > RDF and thus be usable for clerezza, then clerezza might reactivate
> its
> >> > commons-rdf proposal. It would then be up to commons to decide which
> >> > proposal to adopt and under which name.
> >> >
> >>
> >> We (the Apache Commons community) have already stated, that we don't
> have
> >> the necessary knowledge about RDF to make such a decision. I would
> prefer
> >> more people from clerezza joining this ML and build consensus with the
> >> incubating commons rdf community about how an implementation of the RDF
> >> specification should look like.
> >>
> >
> > It might be hard to reach an acceptable solution if the result of one
> year
> > on Github are taken as unmodifiable except when there is 100% agreement
> on
> > a change.
>
> You were privy to all of the public discussions on GitHub, and many of
> the private discussions just before setting up the project publicly.
> Please do not imply that this was your first opportunity to bring up
> these issues, or that we had not responded at all to the issues you did
> bring up in the past.
>
The first discussions we had were at the end of 2012 on public apache
mailing lists.
>
> Apart from the structural constraints of having an entire interface
> driven API, and there being no clear reason why the interface names
> themselves should be changed to suit you,
I've changed clerezza to mach the names in rdf-commons classes. I would
have preferred an decision on a casing conventions rather than just a
statement that these types are named like that and will not change.
> do you have other issues
> where getting ~100 percent agreement has failed and you would like
> some further discussion.
>
I've created COMMONSRDF-13 to address one of the main issues.
>
> > Even without having the commons community diving deep into RDF it might
> > become clear that one API is better suited for triple stores and their
> > requirement while the other is more suitable to exposing arbitrary data
> > source using the RDF model. So if the result is not something that can be
> > used in all usecases having two commons project relating to RDF but with
> an
> > distinct goal might also be an option.
>
> If you could articulate why the current interface based method makes
> it unsuitable for your use cases it would definitely help. In
> particular, some examples of where Clerezza could map a data source to
> RDF somewhow, but it would be impossible with commons-rdf-api, then we
> can start to discuss it further. Right now you have only implied that
> the difficulty exists without articulating it.
>
I've written code that exposes a SPARQL endpoint using the clerezza version
of RDF Commons, I've argued that it would be quite hard to do the same with
the incubating Commons RDF proposal [1]. The reply on the list was that we
will worry about that later, but in my opinion this shows a fundamental
limitation of the current approach.
Besides the SPARQL usecase, here's a simple usecase for wrapping data as
RDF:
interface Person {
String getFirstName();
String getLastName();
String getDiary()
}
interface DataBase() {
Interator<Person> list();
Interator<Person> filterByLastName(String);
Interator<Person> filterByFirstName(String);
}
No the task is to expose this dynamically as RDF (i.e. without duplicating
the data).
Wrapping this with clerezza one would wrap the Person instance in a
blanknode, the identity of the BlankNode would depend on the identity of
the Person instance. Doing the same with the incubating commons rdf
proposal would require keeping a Bidirectional Weak Hashmap of from
Blanknode identifiers to Person objects. I don't think many programmers
would like to do the latter, so I don't think it is currently a suitable
API for exposing arbitrary data using the RDF datamodel.
Cheers,
Reto
1.
http://mail-archives.apache.org/mod_mbox/commonsrdf-dev/201503.mbox/%3CCALvhUEXSSwO-Udj6ngdedVQuPC6n=+983ubnkyobs2psy5k...@mail.gmail.com%3E
