So there it is - my crash course in factories I just spent the last 2 hours
unsuccessfully googling about! Thanks Nando.
I'm also in the process of checking out coldspring - seems clever so far.
So since the Factory is responsible for creating objects it has to have
atleast one method per object - right? Your factory must be hundreds of
methods long...
And why the generic Load() method? Why not call the make methods directly
from your app?
i.e.
<cfset Customer=Factory.makecustomer()>
Instead of:
<cfset Customer=Factory.load('Customer')?
Cheers,
Baz
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of Nando
Sent: Sunday, October 30, 2005 9:02 PM
To: [email protected]
Subject: RE: [CFCDev] Global Function Libraries
>Basic Questions
>
> - What's better, application scope or request scope?
> - Is it not horribly bad to refer to outside scopes form CFCs?
>
I've said this before just a few days ago, but to me, the thing that's "bad"
about it is that you're setting yourself up - to _not_ really learn OO
principles. To me that's "horribly bad" - or at least "kinda bad" ;)
I'd forget about scope in this context (how to get things to work together
using scope) and start to train yourself to think about the architecture of
your app. Your CFC's need to play in harmony together and with the rest of
your app - you're the composer and conductor - how are you going to do that?
One of the keys i'm running across these days is using a Factory to create
your objects. Lemme map out a partial possible solution ...
Instantiate a Factory as a singleton in application scope from your
Application.cfm or Application.cfc. This is the only cfc that's instantiated
outside your Factory - all the rest are instantiated inside your Factory.
In your Factory.init() method, have your Factory instantiate your function
library and place it in it's own variables scope.
Any CFC that needs it gets a reference to the function library passed in
when your Factory creates it.
<cfcomponent displayname="Factory">
<cffunction name="init" access="public" returntype="Factory"
output="no">
<cfargument name="dsn" required="Yes" type="string" />
<cfset variables.dsn = arguments.dsn />
<cfset variables.Utils = load('Utils') />
<cfreturn this />
</cffunction>
<cffunction name="load" access="public" returntype="any"
output="false">
<cfargument name="objectName" required="Yes" type="string"
/>
<cfset var myInstance = "" />
<cfinvoke
method = "make#arguments.objectName#"
returnVariable = "myInstance" >
<cfreturn myInstance />
</cffunction>
<cffunction name="makeUtils" access="private" returntype="Utils"
output="no">
<cfset var Utils = createObject('component','Utils').init()
/>
<cfreturn Utils />
</cffunction>
<cffunction name="makeSomeObj" access="private" returntype="SomeObj"
output="no">
<cfset var SomeObj =
createObject('component','SomeObj').init(variables.Utils) />
<cfreturn SomeObj />
</cffunction>
....
OR another variation ...
<cffunction name="makeSomeObj" access="private" returntype="SomeObj"
output="no">
<cfset var Utils = load('Utils') />
<cfset var SomeObj =
createObject('component','SomeObj').init(Utils) />
<cfreturn SomeObj />
</cffunction>
....
What about when your custom tag needs a UDF? Do you think it would be
appropriate to return the instance directly from the Factory?
<cffunction name="getUtils" access="public" returntype="Utils"
output="no">
<cfreturn variables.Utils />
</cffunction>
Or would it be better to have it available from a singleton Service object
that's available to the rest of the app?
In Factory
<cffunction name="makeServiceObj" access="private"
returntype="ServiceObj"
output="no">
<cfset var ServiceObj =
createObject('component','ServiceObj').init(variables.Utils) />
<cfreturn ServiceObj />
</cffunction>
Out in the rest of the app:
application.ServiceObj.getUils().someFunc()
I'm not sure. It probably depends some on if you need a ServiceObj that
needs Utils anyway, and your preferences. The point here is that the Factory
gave us a clean and easy way to create and compose objects, all in one place
in our application. The question about whether to use request or application
scope disappeared when we replaced it with a better question ... how can i
create and compose my CFC's easily?
:) nando
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