How to create a Treemap and portray it through flex?

So basically I'm trying to do something like this: http://store.kapit.biz/demo/treemap/prod/index.html#

I searched for a long time and it is difficult to find a site that will show me some kind of pseudo-code (at least) or an algorithm for implementing this type of application. But all I find is only applications that take data and do all the work for me to create a graph. I need to create it for myself, just now. Does anyone know where I can find this? What I want is to take the data from the database and use it to create a treemap, and then express it in the GUI, as in the link above. If any specificity is needed, I can provide it. I am trying to do this in Flash Builder using Flex and use ColdFusion as a backend. Thank!