he thread-scoped value
 of a policy context identifier by calling the static
 <code>setContextID</code> method. The value of a thread-scoped policy 
 context identifier is available (to <code>Policy</code>) by calling the
 static <code>getContextID</code> method.
 <P>
 This class is also used by <code>Policy</code> providers to 
 request additional
 thread-scoped policy relevant context objects from the calling container.
 Containers register container-specific <code>PolicyContext</code> handlers
 using the