Question

In Adobe ColdFusion, if

<cfset Application.obj = CreateObject("component","ComponentName")>
<cfset myResult = Application.obj.FunctionName()>

I’m concerned that a var declared in the function’s local scope might have concurrency problems because Application.obj is stored in the Application scope.

<cffunction name="FunctionName">
<cfset var local = {}>
(pretend some long process happens here)
<cfif condition>
   <cfset local.result = True>
<cfelse>
   <cfset local.result = False>
</cfif>
<cfreturn local.result>

If two people are in that function at the same time, will the result for person 1 corrupt the result for person 2?

Answer 1

Yes, there is the potential for a race condition in your code sample.

You will need to use a lock around

<cfset myResult = Application.obj.FunctionName()> 

to prevent the race condition.

The type of lock to use would depend really on what the long process is doing.

If you are instantiating your framework you might consider double-checked locking. (Joe Rinehart, author of Model-Glue had a great post on this but his site isn’t responding atm.)

If the long process is less critical you could use a simpler lock.