Cairngorm 3 & Dynamic Modules

Thanks Tom,

The way I solved this previously was via a LoadModule event, which was

derived from the profile downloaded for the logged in user. This was based

on a simple "there can be only one" module of a given type.  The module was

loaded into a ViewStack and as part of its instantiation, loaded necessary

data assets. The issue I ran into as the unloading of the module.  Some

modules would load/unload with no memory leaks a some wouldn't.  I spent

quite a bit of time with the profiler trying to figure out why. Binding

would seem to be a possible liability as when using quick and dirty MXML

binding, the references were hard.

I was very excited to read the Parsley docs about modules and contexts. If

the context that the module is relying on is destroyed on unload, that would

seem to address the issues with the module not unloading cleanly, so long as

the view is bound to model objects with weak references.

In the case of Cairngorm and Parsley, injection should be used instead, but

the question becomes how to perform that injection in ActionScript vs. MXML.

That's what leads me toward a global Module factory class that would deliver

a fully configured module based upon a descriptor and add that to the

appropriate landmark in the view hierarchy.

Jeff

I decided to throw caution to the winds and attempt to port an existing application over to CG3 with modules - but with the modules hard-coded like they are in the sample CG3 app.  I'm treating this as sort of a tutorial to get up to speed with CG3 and Parsley.  I've been able to get the modules to load correctly but run aground on commands.  Events fired in the module's context don't seem to want to communicate to Comands declared in the same context.  Basically the messaging 'sub-system' isn't working and I haven't been able to figure out what I'm doing wrong.

Any advice appreciated.

Jeff

Thanks Alex,

I believe that I've got all the dependencies downloaded from the trunk and in the build path:

Module

Navigation

Integration

IntegrationRPC

Task

parsley-complete-flex3-2.1.0.swc

spicelib-complete-flex-2.1.0.swc

Here's the PM that is dispatching the event:

ilc.modules.timeline.presentation

{

import flash.events.EventDispatcher;

import ilc.modules.timeline.GetDecadesEvent;

Event(name="getDecades", type="ilc.modules.timeline.GetDecadesEvent")]

[ManagedEvents(

"getDecades")]

public class TimelinePM extends EventDispatcher

{

public function TimelinePM()

{

getDecades();

}

public function getDecades():void

{

new GetDecadesEvent());

}

}

}

Here's the Command class:

import ilc.modules.timeline.GetDecadesEvent;

import ilc.modules.timeline.domain.Decades;

import mx.collections.ArrayCollection;

import mx.rpc.AsyncToken;

import mx.rpc.events.FaultEvent;

import mx.rpc.events.ResultEvent;

import mx.rpc.remoting.mxml.RemoteObject;

public class GetDecadesCommand

{

public function GetDecadesCommand()

{

}

[MessageDispatcher]

public var dispatcher:Function;

[Inject]

public var decades:Decades;

'remoteService')]

public var service:RemoteObject;

[Command]

public function execute(event:GetDecadesEvent):AsyncToken

{

trace('getting decades');

return service.getDecades() as AsyncToken;

}

"getDecades")]

public function serviceResult(event:ResultEvent):void

{

new ArrayCollection(event.result as Array);

}

"getDecades")]

public function showError(fault:FaultEvent):void

{

trace(fault.toString());

}

}

}

Do you see anything obvious?

Jeff

I'm beginning to think there's something up with the way I'm creating the child contexts - as my PM that should have been injected into one of the views in the heirarchy, but it's null.   It should be as simple as creating a new config,mxml in the module itself - should it not?

Jeff

Thanks Tom (and Alex),

I'll check the Parsley docs on how to refer to the parent context.  In the case of modules it would seem to me that the model objects would want to live exclusively in the context of the module - am I right?

What I am noticing in the case of my module is that the context is available at the module view heirarchy level but not available in any child views, even if I have included them in the context definition and have fired off the 'configureIOC' event from within the view.  In the app I am converting, the module contains another view which I am injecting my PM into, and the PM keeps coming back null.

Even still, though, when I am firing my event which should result in command class getting executed in my module, the messaging does not appear to be working.

Jeff

Tom,

A further development: if I use the MessageHandler metatag instead of Command, it works (at least in the immediate context of the module).  Am I correct that the Command extensions are in the Integration.swc?  I checked out the integration libraries have referenced the Integration.swc from my test project. Is there another dependency that I'm missing?

Jeff

Alex,

I did not have the integration libs tag in my module - only at the top level of the app That was it!!!!!! - thank you and Tom for hanging in there on this.

However, I'm still not getting my model injected into a view child of my module. I switched to ViewConfigurationEvent.CONFIGURE_VIEW to ensure that there was nothing up with my spelling but no, my child view still isn't getting injected with my model, even though I have the view in my context definition.

Jeff

Tom, Alex,

Although my understanding of C3 is progressing, it is far from what it should be.  The most frustrating part of this is getting the data retrieved by a Command back into the model.  It appears that the PM model that I might be injecting is not singleton or possibly may exist in more than one scope.  I've tried passing a reference to my target model in a Managed event, but so far no dice.  Almost makes me wish for a ModelLocator.

Jeff

Alex,

I have been into the Parsley docs quite a bit.  Just gotta keep pushing until I fully assimilate the pattern of development.

Jeff

Alex,

I admit to being completely confused at this point.  I fire off a managed

event which invokes a Command, which returns an array, everything seems to

be fine, but the reference if the model object that's being updated is not

the one I referred to.   It's almost as if the context and my normal Flex

view aren't talking to each other.  It's like the context and view are in

parallel universes.  And I still have the issue where subviews aren't

getting processed by the context upon instantiation.

I'm quite sure I am **** something wrong - I'm comparing my source code

against the sample insync extended app and trying to identify where I've

gone astray...

Jeff

Alex, Tom,

I'm making some incremental headway but it is slow going as I try to figure out whether the behavior I'm seeing is the result of my inexperience with Parsley or possible bugs in the framework itself.  Here's what I've been able to accomplish so far:

I've got my shell app working with modules being loaded on demand - not dynamic modules mind you - but hard coded at this point. Works fine.

I've also been able to get my Commands to send results back to the view - this works but things go awry when I have a subview to the module.  I can inject the child view, but the child view keeps getting added/removed/added into the context and my RPC calls are duplicated.  In the end, the bindings from my model to the child view's components don't get executed.

Jeff

Tom,

I was wondering if you've been working on runtime module configuration and if there's been progress in that area.

Jeff

Thanks, Tom.

My particular use case is pretty darned simple - user profile maps to

available modules and navigation reflects this.  When navigated to for the

first time, the module is loaded into a view stack. In my app, there's only

area that loads modules.  So what we really have is a shell application with

modules loaded on demand.

I guess my question is, would a simpler approach be more appropriate for my

app? Conceivably it could be as simple is sending a message that a certain

module should be loaded (with it's url, etc), and the selectedIndex of the

ViewStack changed accordingly.

Jeff

Tom,

That looks great!  Nice collaboration between you and Jens! 

Jeff