Getting list of all users that are currently connected

Question

Possible Duplicate:
JSF J_security_check How to get number of connected users and their role?

I already know that this line takes care of getting the current logged-in user in a JSF 2 application:

     connectedUserName = FacesContext.getCurrentInstance().getExternalContext().getUserPrincipal().getName();

Is there any way can I get a list of all users that are currenty logged-in the web JSF 2 application?

Thanks in advance...