ActionScript 3.0 :: Flash Variable Monitoring From Outside Class

I am attempting to make a simple class that I use to debug some of my code at runtime. I use a function in my debug class to pass a variable from another class that I want to monitor in realtime. For simplicity sake I am only passing Stings at the moment. I can pass the variable that I want successfully but I am stumpted as to how I to get my DebugClass to monitor that variable in realtime. Since the variable is being altered in another class, what would I needto do to have the debugClass monitor that variable without having to call a new function everytime the varible changes, which could be 300+ times a minute.

This is the current method I use to add the variable to my displayList:

protected function addDebugData(stringToAdd:String):void{
var debugText1:TextField = new TextField();
debugText1.border = true;

[Code]....