Thanks Ray...this is helping me get a clearer picture on locking in MX.
Maybe a couple of examples might help me, to be sure. Please let me
know if my assessment is correct or not. Thanks again.
1)
<cfset application.dsn = "foo"/>
Does NOT need to be locked.
2)
<cfif isDefined( 'url.clearCart' )>
<cfset session.cart = arrayNew(1)/>
</cfif>
DOES need to be locked because other threads could be reading from
session.cart.
3)
<cfset session.breadCrumb = arrayAppend( session.breadCrumb, 'Product
Details' )/>
DOES need to be locked because other threads could be reading or writing
to session.breadCrumb.
4) (In a CFC that has been instantiated into the application scope)
<cffunction name="init">
<cfset myInstanceVar = "default" />
</cffunction>
Does NOT need to be locked (either inside the CFC or where the init()
method is called) assuming that the init() method is a constructor and
will only be called once, when that object is instantiated.
5) (In a CFC that has been instantiated into the application scope)
<cffunction name="setInstanceVar">
<cfargument name="aValue"
<cfset myInstanceVar = arguments.aValue />
</cffunction>
DOES need to be locked (either inside the CFC or where the
setInstanceVar() method is called) if other threads could be reading
from myInstanceVar.
Am I close, or way off base? Thx.
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Raymond Camden
> Sent: Wednesday, December 03, 2003 5:15 PM
> To: [EMAIL PROTECTED]
> Subject: RE: [CFCDev] Basic CFC Design Question
>
> > But Ray, in the example you used, you are clearly NOT sure
> > that your variable will only be written to once. Right?
>
> No. Again, it is a waste of time to set application.dsn more
> than once, however, it's is a very trivial waste of time.
>
> > So if you did:
> > <cfif not isDefined( 'application.dsn' )>
> > <cfset application.dsn = "foo"/>
> > </cfif>
> >
> > Then you would not need to lock it.
>
> That is not what you said though. The code above CAN be run
> twice, because two (or more) threads can read the isDefined
> line and both see false. Again though, its not a big deal.
>
>
> >But doing it the way you
> > show, with no check for it's presence before writing to it,
> > you would need to lock it, and then lock all reads to it as
> > well. Correct?
>
> No. Again, assuming MX, it doesn't matter if N threads read
> the value while its being set if it is static.
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