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Re: [epsilon-dev] Concordance Model object creation
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Hello,
I have committed these changes.
I have not added an exception when the extension point is used multiple times,
in its description the following is written:
Note: Make sure to register only one factory, otherwise the factory that is
going to be actually used might be unknown/unexpected.
Unfortunately something went wrong and the three commits I had were merged...
So the commit message (the one commit) is unfortunately not complete :(
I will close the related bugs.
Cheers,
Maarten
On Wednesday 12 February 2014 23:17:18 Dimitris Kolovos wrote:
> Hi Maarten,
>
> I think I'd prefer the extension point.
>
> Cheers,
> Dimitris
>
> On 12 February 2014 14:05, Maarten Bezemer <maarten.bezemer@xxxxxxxxx>
wrote:
> > Hi,
> >
> > True...
> >
> > It could check if it has been called earlier and throw an exception, so
> > the
> > developer is informed of the problem.
> > Basically this means that the used plugins are incompatible, as they both
> > required their own IConcordanceModel implementation, which is not possible
> > as one *must* be chosen.
> > In such a situation, other things are probably clashing between these two
> > plugins as well, since the IConcordanceModel implementation is used when
> > the models need to be managed a certain way (e.g. by using the
> > EditingDomain(s) of the application).
> >
> > What would be your preference? using an extension point or the static
> > method? (Both could throw an exception when used twice)
> >
> > Cheers,
> >
> > Maarten
> >
> > On Wednesday 12 February 2014 11:46:48 Dimitris Kolovos wrote:
> >> Hi Maarten,
> >>
> >> Switching to a static method may not necessarily make the problem
> >> disappear as two different plugins can still call the static method
> >> and the order in which they do this may not be predictable.
> >>
> >> Cheers,
> >> Dimitris
> >>
> >> On 12 February 2014 10:34, Maarten Bezemer <maarten.bezemer@xxxxxxxxx>
> >
> > wrote:
> >> > Hi Dimitris,
> >> >
> >> > The last provided factory will be used...
> >> > But, the order of plugin activation might be obscure/unknown, so which
> >> > one
> >> > is activated last is (probably) unknown by the user.
> >> >
> >> > This might be a reason to provide the static method instead of the
> >> > extension point.
> >> >
> >> > Basically it does not make sense use the extension point twice, as this
> >> > switches the IConcordanceModel implementation for newly created
> >> > objects,
> >> > while still having the existing object that use the old
> >> > implementation...
> >> >
> >> > Currently, I have added a message/note to the extension point
> >> > description
> >> > to notify the user about this and that the extension point should be
> >> > used
> >> > only once (per application).
> >> >
> >> > I could add a warning/log message to notify the user when the extension
> >> > point was used multiple times..?
> >> >
> >> > Cheers,
> >> >
> >> > Maarten
> >> >
> >> > On Wednesday 12 February 2014 09:44:37 Dimitris Kolovos wrote:
> >> >> Hi Maarten,
> >> >>
> >> >> What will happen then if two plugins provide extensions to the
> >> >> extension
> >> >> point?
> >> >>
> >> >> Cheers,
> >> >> Dimitris
> >> >>
> >> >> On 11 February 2014 12:26, Maarten Bezemer <maarten.bezemer@xxxxxxxxx>
> >> >
> >> > wrote:
> >> >> > On Tuesday 11 February 2014 11:15:59 Dimitris Kolovos wrote:
> >> >> >> To avoid confusion I'd suggest calling it an IConcoranceModel
> >> >> >> instead
> >> >> >> as there's already an IModel in Epsilon
> >> >> >
> >> >> > http://dev.eclipse.org/svnroot/modeling/org.eclipse.epsilon/trunk/pl
> >> >> > ugi
> >> >> > ns/
> >> >> > org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/models/IM
> >> >> > ode
> >> >> > l.j
> >> >> > ava
> >> >> >
> >> >> > I indeed noticed the other IModel interface, AFAIK there is also
> >> >> > another
> >> >> > Model class. I could also rename the concordance Model class to
> >> >> > ConcordanceModelImpl.
> >> >> >
> >> >> >> >> Next thing is to be able (as an user of Epsilon/Concordance) to
> >> >> >> >> provide a
> >> >> >> >> custom implementation of the Model interface.
> >> >> >> >> Currently, I used an extension point to register my custom
> >> >> >> >> factory
> >> >> >> >> (implementing a new IModelFactory interface) which creates my
> >> >> >> >> custom
> >> >> >> >> implementation of IModel.
> >> >> >> >>
> >> >> >> >> This works nicely and is least intrusive I think.
> >> >> >> >> By default the ModelFactory implementation is used creating the
> >> >> >> >> default/current Model objects. So nothing changes for existing
> >> >> >> >> users.
> >> >> >> >>
> >> >> >> >> But, (mis)using an extension point to 'configure' the
> >> >> >> >> ModelFactory
> >> >> >> >> seems
> >> >> >> >> wrong? Instead a public static method could be called to
> >> >> >> >> register
> >> >> >> >> the
> >> >> >> >> factory, although this does not seem very nice as well and might
> >> >> >> >> result
> >> >> >> >> in
> >> >> >> >> the default factory being used until the call is made (which
> >> >> >> >> might
> >> >> >> >> also
> >> >> >> >> be
> >> >> >> >> the case using extension points...)
> >> >> >>
> >> >> >> One option would be to introduce a preference page that would allow
> >> >> >> users to select the model factory they'd like to use (extenders
> >> >> >> would
> >> >> >> still contribute model factories through the extension point).
> >> >> >
> >> >> > Letting the user choose the IConcordanceModel implementation does
> >> >> > not
> >> >> > make
> >> >> >
> >> >> > much sense:
> >> >> > * Without the correct implementation applications (might) break
> >> >> > (applications>
> >> >> >
> >> >> > must choose)
> >> >> >
> >> >> > * Users do not care what model implementation is used, it just need
> >> >> > to
> >> >> > work.>
> >> >> >
> >> >> > So, I do not think that a preference page is the way to go..?
> >> >> >
> >> >> > Another possibility (to circumvent extension points) would be to
> >> >> > directly
> >> >> > call a (static) method of the IConcordanceModel factory, to
> >> >> > 'configure'
> >> >> > the required model type. But personally I (slightly) like the
> >> >> > extension
> >> >> > point better, as this seems more 'natural' and less of a hack.
> >> >> >
> >> >> > Cheers,
> >> >> >
> >> >> > Maarten
> >> >> >
> >> >> > _______________________________________________
> >> >> > epsilon-dev mailing list
> >> >> > epsilon-dev@xxxxxxxxxxx
> >> >> > https://dev.eclipse.org/mailman/listinfo/epsilon-dev
> >> >
> >> > _______________________________________________
> >> > epsilon-dev mailing list
> >> > epsilon-dev@xxxxxxxxxxx
> >> > https://dev.eclipse.org/mailman/listinfo/epsilon-dev
> >
> > _______________________________________________
> > epsilon-dev mailing list
> > epsilon-dev@xxxxxxxxxxx
> > https://dev.eclipse.org/mailman/listinfo/epsilon-dev
