[squeak-dev] Re: An old gripe (or: SystemChangeNotifier +
Announcements = Sanity?)
Andreas Raab
andreas.raab at gmx.de
Fri Mar 6 07:36:22 UTC 2009
nicolas cellier wrote:
> Sure. ++ for Announcements.
> But one thing just annoys me: uncontrolled proliferation of #is* messages.
> Why general Announcement framework should know about every specific annoucement
> for example implementing isMethodRemoval ?
Ah! But that's one of the points of using Announcements. You don't have
to add it too high in the event hierarchy, since you can scope down to
where you need it. E.g., consider this hierarchy:
Announcement
SystemEvent
CompilationEvent
ClassCompilationEvent
ClassAdditionEvent
ClassModificationEvent
ClassRemovalEvent
MethodCompilationEvent
MethodAdditionEvent
MethodModificationEvent
MethodRemovalEvent
Now, only CompilationEvent does need to know about #isMethodRemoval
since you can do, e.g.,
registerForEvents
SystemChangeNotifier
on: CompilationEvent
send: #prefEvent:
to: self.
Cheers,
- Andreas
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