Comments on: A better way

By: Sanan Murad

Sanan Murad — Wed, 31 Mar 2010 20:19:58 +0000

Great work!
I had application developed in flex and then I had to develop iphone version of it. And it appears that using notification center allows more flexibility and objects decoupling than AS event dispatcher. I was going to develop it myself but luckily you did it already. I’ll definitely use it on next update.
Thanks a lot again.
Sanan Murad

By: RaiulBaztepo

RaiulBaztepo — Sat, 28 Mar 2009 22:32:12 +0000

Hello!
Very Interesting post! Thank you for such interesting resource!
PS: Sorry for my bad english, I’v just started to learn this language
See you!
Your, Raiul Baztepo

By: Jethro Grassie

Jethro Grassie — Tue, 03 Mar 2009 22:02:29 +0000

@flashape You are certainly missing something (though easily missed)!
There is a great deal of flexibility in the NSNotificationCenter in that it can be a global dispatcher/manager of notifications but can also be modular.
It also allows for a great deal of flexibility of the observers as to which notifications they receive.
In this respect the coupling can also be way looser.
You are not forced to subclass anything nor use anything else.
These are very lightweight very reusable classes.

By: flashape

flashape — Tue, 03 Mar 2009 21:52:17 +0000

Am I missing something, or is this just a global event dispatcher? Doesn’t seem that much different than CairngormEventDispatcher or even the SystemController from Grant Davies’ Arp extensions from way back when (http://theresidentalien.typepad.com/ginormous/2005/10/extending_arp.html).

By: NSNotificationCenter JavaFX port

NSNotificationCenter JavaFX port — Tue, 03 Mar 2009 21:08:31 +0000

[...] on from my last post, here I have now added a JavaFX [...]

By: Jethro Grassie

Jethro Grassie — Tue, 03 Mar 2009 08:36:58 +0000

@didier, I didnt bother to do the Java version as I found a port online. Though I may have a look at a JavaFX specific version soon.

As for usage of Flex events compared to NSNotificationCenter, personally I think Flex events should be used where they fit best and that certainly means anything on the display list.
There is no point sending a notification for a button click when the W3C event model is already there, implemented and works well.
Another place is data binding.

However, I feel anywhere else is game for NSNotificationCenter because of its lose coupling. It makes classes far *more* reusable rather than less.

Specific to modular Flex applications, the defaultCenter should only be used where inter-module communication is needed.

On a side note… didier your blog theme looks great.

By: didier

didier — Tue, 03 Mar 2009 00:01:48 +0000

This is great for propagating events in a non-tree structure–which falls out of the scope of the W3C DOM Event model!
Thanks for porting this. (It may be useful in JAVA, too!)

On the architecture side, one must be careful, though, not to overuse the dependency to the Notification Center across independent subsystems of an application. The “defaultCenter” has drawbacks similar to the Singleton’s. The easy coupling to the Notification Center may reduce the re-usability of involved classes. So, for Flash/FLex programming, as great as this is, I would restrict its use for (internal) data notification within a self-contained business vertical subsystem, and use regular (Flash/Flex) events for notifying outside of that subsystem.

This is a great tool, which should be part of the AS3 API. Thanks!