[mcclim-devel] Push or Pull data in application

[Oliver Uvman]

Hello!

I'm now beginning to write my first GUI with McClim, and there seem to
be an abundance of interface-building resources, so I'll be able to
keep going for a while without help. I am writing this as an
additional user interface to our backend program.

The backend is a calendar program used at my university (Linköping
University) to teach abstraction. The idea is that either manual
interaction with the backend or interaction via the Clim frontend can
be used, at the same time or separately. Anything done in one should
be observable in the other.

The problem I know I will eventually run into is updating the Clim
interface when changes to data have been made through manual
interaction with the backend. The solutions are either push or pull
based, I guess. Push based is not really prefered, because the backend
would have to keep track of the gui so it can send messages to it. We
need to keep the backend as simple and clean as possible, because it
is to be modified by the students. Thus I would rather prefer a
pull-based approach where, every 80-90ms or so the application itself
requests up-to-date data from the backend and redraws if necessary. Is
there a standard way to go about this? It seems like it is a problem
that would appear in almost any application.

Regards,
Oliver Uvman