refreshing the GUI

Derek Atkins warlord@MIT.EDU
29 Nov 2000 12:46:30 -0500

James LewisMoss <> writes:

> So a change to data occurs.  The engine has a registered listener in
> the GUI Component Manager that it calls to say something has changed.
> What happens then?

I suspect that the GUI Component Manager then calls all the components
that registered a callback for that particular object.

> I'm trying to figure out what the close, find and iteration callbacks
> are meant to do and who registers with who.

The components register with the Component Manager (CM), which then
collects the requests and registers with the engine.  Basically, you
can think of it this way (assuming I "get it"): the CM is the
local-exploder for the GUI callbacks; each 'window' can register for
the callbacks it wants, but only one set of callbacks get registered
between the engine and the CM.

When a piece of data changes, the engine calls back to each CM that
registered for that object, and each CM then calls each component that
registered.  The CM can also allow a single GUI to turn on/off the

At least, that's how I _think_ he plans to do it.

The hard part, IMHO, is controlling the batching.  How do you know
when a batch is done, or how do you chunk it?

> jim


       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL:      PP-ASEL      N1NWH
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