[FIX] Publish-subscribe event system

Stefan Matthias Aust sma at 3plus4.de
Sun Apr 23 14:35:07 UTC 2000


At 16:56 17.04.00 +0000, you wrote:

>Stefan, do you have any examples on using the publish-subscribe event
>system?  I'm looking for some toy examples to get a feel for how to
>use it and what it affords.

Unfortunately, not at the moment.  The system is very similar to the usual 
update/changed mechanism although a little bit more efficient.  See 
Object's events protocol for all methods.  Use

when: anEventSymbol send: aSelector to: anObject

to register "anObject" as a listener (to use the Java jargon) for 
"anEventSymbol". Let's say you've an application which is interested in 
mouse clicks and a button widget which can trigger #clicked events.  Then 
you'd use

button when: #clicked send: #buttonClicked to: application

to register the listener and then provide a method 
Application>>buttonClicked which will be called then.  The button will 
eventually trigger events using

trigger: anEventSymbol

Variants of these methods are used to pass arguments from the event source 
to the event handler method.

bye
--
Stefan Matthias Aust // Bevor wir fallen, fallen wir lieber auf





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