functions provided by this class 
 allow per-thread policy context values to be
 established and communicated independent of a common reference to a 
 particular PolicyContext instance. 
 <P> 
 The PolicyContext class may encapsulate
 static ThreadLocal instance variables to represent the policy context
 identifier and handler data values.
 <P>
 The Application server must bundle or install the PolicyContext class, and 
 the containers of the application server must prevent the methods of 
 the PolicyContex