Additional user management

Hello,

I would like to create a sort of my own user management function for users (front and back ends) in addition to joomla's one. I have additional data on another server, so i need to check every user against the data on that server and redirect where needed.

Example: BEFORE executing the logic (i.e view item) ill check for my var (variable) on session for that user (as far as i know Joomla creates JUser object for every request, hence we always can JFactory::getUser()) if it not exist then ill get my var from another server for current user and then set it on the session for next time.
If the user have no data from another server then that user should get error message and not process his request (i.e. no access to item).

1. My 1st thought was to find where Joomla creates JUser object and sets it on request and at that point insert my logic .
Problem is i can't find where (what php file) Joomla / Flexy is initially creating and populating the JUser object.
Can you guys help to find it ?
(Or if you have any other ideas / suggestions i would be glad to hear)

Thanks,
(p.s. - To make it more clear i would like to bring as example the JAVA servlet filter, which can execute checks / tasks prior request's arrival to the controller)

Hello

this is a Joomla question and not FC specific

and you want to locate and hack the Joomla JUser class ?

try doing a folder text search for
"class JUser"

hi,
Thanks for pointing out that creation of the JUser object is happen within Joomla itself.
Well i guess i will have to use some hack but essentially
my purpose is to insert my logic somewhere in the beginning of the request's cycle, like where Joomla creates the JUser object and "hack" that file for my own logic, so i guess what i'm asking if anyone knows where joomla creates JUser object and puts it on request for the rest of logic (since we always can check if user is guest or not and get other info, i want to find the place joomla puts all that info for our later use...).

My second thought was maybe use of some sort of main controller (i'm sorry, i'm still not familiar with joomla's core structure). So if there is some main controller where every request pass trough then i think its a good point to make my changes. Unfortunately i'm not aware of such controller and as far as i know every component has its own controller, but is there any main one for all of the requests ???