[Seaside] rendering in a class hierarchy, part 2

[Stephan Eggermont]

Using Announcements could use some extra detailed explanations:

Create an Announcement subclass  
SomethingInterestingHappenedOnDefaultDisplay

Create a subclass of WASession having an announcer instance variable
and lazy initialized getter

MySession:announcer
	^announcer ifNil: [announcer := Announcer new]

This announcer handles the session specific announcements. You might  
have
an application one to handle session-to-session announcements, or
component specific ones to handle very complex interactions.

In MADefaultDetailDisplay, you create a method:

somethingInterestingHappened
	self session announcer announce:
		SomethingInterestingHappenedOnDefaultDisplay

that you calll somewhere in the component, e.g.:

renderContentOn: html
	html form: [
		html submitButton
			on: #somethingInterestingHappened of: self]

In your page you subscribe in initialize to this Announcement:

initialize
         super initialize.
        details := MADefaultDetailDisplay new.
	self subscribeToDetails

subscribeToDetails
	self session announcer
		subscribe: SomethingInterestingHappenedOnDefaultDisplay
		send: #switchToOtherDetail to: self
" add handling other details"

switchToOtherDetail
	detail := MAOtherDetailDisplay new.


Stephan Eggermont