[CFCDev] Optimal Function Library

[Mike Chabot]

I would like to have a library of functions that contains code for database 
maintenance. My choices are custom tags, a file with UDFs that I cfinclude 
in the page, or a CFC. For efficiency, I was thinking that a single CFC 
object that was resident in the server scope would be the most efficient to 
call. The CFC would only contain methods, no properties.

I was looking for a good way to do this and came across Brendan O'Hara's 
article on the Singleton pattern. 
<http://www.sys-con.com/coldfusion/article.cfm?id=624>. This is essentially 
what I am looking for, but I do not see how this strategy will increase 
operational efficiency for my function library.

The article basically says that you run a line of code such as
<cfset x=createObject("component","components.maintenance").init()>.
Inside the init() function, you have all the locking and existence 
checking. If the server CFC does not exist, you create it. The init() 
function returns the server CFC.

My understanding of what happens is that a local copy of the maintenance 
CFC is instantiated, then immediately replaced by the CFC that is already 
in the server scope. However, this seems to defeat the purpose of caching 
the CFC in the server scope, which is to prevent me from having to 
instantiate the object. In fact, since the CFC only consists of static 
methods, the local CFC that has a brief life would be exactly the same as 
the CFC in the server scope.

To create a singleton object without any wasted instantiations, I was 
thinking that the better strategy would be to cfinclude a file which 
contains the following code:

<cfif NOT structKeyExists(server,'maintFunctions')>
            <cflock timeout="10" throwontimeout="No" name="maintFunctions" 
type="EXCLUSIVE">
            <cfif NOT structKeyExists(server,'maintFunctions')>
                        <cfif NOT structKeyExists(server,'maintFunctions')>
                                    <cfset 
server.maintFunctions=createObject("component","components.maintenance").init()>
                        </cfif>
            </cfif>
            </cflock>
</cfif>

I timed both methods by running them through a loop 1000 times. The first 
"createObject" version takes 16 seconds, while the second "cfinclude" 
version takes 2 seconds. Clearly the method where the server instance is 
returned by the init() function is very wasteful, and if I were to 
implement a cached CFC, I would cfinclude the code to handle the existence 
checking.

So my question is, what is the best way to have a library of functions in 
CFMX 6.1? Would my CFC stored in the server scope be more efficient than 
custom tags or cfincluding a UDF file? As far as manageability, I think all 
three methods are roughly equal, although with a cached CFC I will have to 
delete the server variable whenever I make a change to the file.

Thank you,
Mike Chabot
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