[Newbies] "Callback" design pattern

[Stephen Davies]

Hi,

I've been busy with hooking Squeak to Asterisk via the Asterisk
FastAGI protocol.
I also want to write code to talk to the Asterisk Manager Interface.

In both cases I need to write an interface to allow others to
"register" to hande particular AGI call, or to "register" to hear
about particular AMI events.

I suppose the method of callback will boil down to "call method
#whatever on object anObject", or maybe you could register a block to
be evaluated.

Now I'm sure there must be an established way to do this in Squeak and
I'd like to use it.  Or at least code mine in the "usual style".

So could someone point me at some classes in the system that I should look at?

Thanks,
Steve