Comments on: String Concatenation optimization

By: ColdFusion Array : pass by reference or Value. « ColdFused?

ColdFusion Array : pass by reference or Value. « ColdFused? — Wed, 15 Jul 2009 12:54:46 +0000

[...] rightly pointed out in my last post that since ColdFusion array are always passed by value, the second technique can not be used if you [...]

By: Rupesh Kumar

Rupesh Kumar — Thu, 05 Jul 2007 16:54:00 +0000

@Crish, you are right.
There is a small mistake there. Since there are many append methods in StringBuffer class, CF did not know which one to invoke. Replace the line

with

and it will work fine.

By: crish

crish — Mon, 02 Jul 2007 09:10:00 +0000

Hey Rupesh,

this code is not working?

createObject("java","java.lang.StringBuffer")>
cfloop from=1 to=100 index=i>
cfset sb.append("something")
cfset sb.append(i)
/cfloop>
cfset result=sb.toString()

By: Rupesh Kumar

Rupesh Kumar — Tue, 06 Feb 2007 14:21:00 +0000

Nice point Ben ! If you want to build it over some method calls, you should not use ColdFusion array. StringBuffer is your best friend in that case

By: Ben Nadel

Ben Nadel — Tue, 06 Feb 2007 13:36:00 +0000

One thing that I wanted to point out (that might not be thought of by all) is that Arrays are passed by value where as Java objects are passed by reference. What does this mean for string concatenation? Not much, unless you have some sort of recursive function or something that builds a string over a bunch of method calls. Using a Java String Buffer, you can keep passing the buffer object to the methods as an object to write to without worrying about the overhead of object copying.

If you try to do the same with a ColdFusion array, it's structure will get duplicated with every method call (passed by value) which will have some performance implications.

So, again, good tip, but here's just another angle to contemplate that might not be obvious.