This class is the interface between the policy domain classes
and the Policy manager, it provide the data to the PolicyManager
in a more native format then in the domain objects
It also caches the policy information for multiple
access.
Security Manager is the main interface to the BusinessFunction and Component Security Architecture.
It provide a mechanism for setting the security context for a thread of execution, and then
provide a guard for securing code in that thread.
This class is used by the Tag Libraries that implement security
It is design to give access to the security manager such that a
context can be pushed onto the thread context stack and then popped off.