Comments on: Cairngorm Command Flaws and What You Can Do About Them

By: kevin

kevin — Fri, 05 Mar 2010 08:01:52 +0000

Hi Jesse,

I’m reviving an old thread here to get your current thoughts on how to handle the issue of notifying a view when a Command has executed and returns its OnResult/OnFault so that further logic can be executed…

As I understand it Cairngorm 3 proposes extrapolating all methods of a view into it’s own model (singleton) which you can then call from the Command/Responder’s Result/Fault handlers.

While I haven’t attempted to use the beta yet, this seems like a lot of remodelling is required!

http://opensource.adobe.com/wiki/display/cairngorm/HowToUseCairngormIntegration#HowToUseCairngormIntegration-Command

Do you have any update on how you’ve solved this problem since 2007?

By: visweshwar

visweshwar — Thu, 11 Dec 2008 03:22:13 +0000

I absolutely agree with Jess. There is a small trick which can enable us to break the shackles of command logic. By using viewcontroller..
an implementation of the same is available at

http://www.flex-lcds.blogspot.com

By: Andre

Andre — Wed, 19 Dec 2007 17:03:45 +0000

Hey Jesse,

Did you ever reply to David’s last thread? I was also curious about the data typing of the events that you passed up to parent views. Thanks for a great post!

By: David

David — Fri, 13 Jul 2007 11:28:03 +0000

Hey Jesse,
love your work,
quick couple of questions, the events you launch from the children how do you type them? that is to say do you create events that are Cairngorm events, but dispatch them as normal flex events using dispatchEvent(myCairngormEvent) and then when you arrive at the appropriate parent re dispatch them as cairngorm events myCairngormEvent.dispatch(), or do you do it some other way? If they are not cairngorm events how do you pass data up the views?

Second I have created individual models for any parent view that is significant, i.e. has several children that have no model and do NOT dispatch cairngorm events, these intermediate parent views also belong to another view (lets call him the super parent). I have been dispatching Cairngorm events from these intermediate parent views that effect their particular model and also dispatching normal events up to their super parents for events that effect them, the super parent then calls its specific cairngorm events as required, is this ok?

By: Vic

Vic — Sun, 27 May 2007 08:49:28 +0000

Great Article. Can’t say that I haven’t had similar problems. I greatly dislike observing the model to see what my commands are doing… sometimes that works but it’s not my preference. I also bubble up from components to app specific views and then dispatch my CG Events from there. One approach I have been using for a while and it works fine in situations where only the calling view and/or it’s children need to know about command status, is to have my views implement an interface, say IVIew, and then pass a reference to the view with my Event. Command checks if the event.token.originatingView is IView and if so calls update(originalEvent, resultEvent). In the update I can then use a switch statement to react to only originalEvent.types that I select.

In situations where multiple lateral views might need updates, i’ve been playing with a generic CommandEvent that all Commands trigger. The type of the original event that triggered the Command is used by Views to filter out events they arent interested in. It works but I fear won’t be very scalable.