With the present invention, it is possible to add {HEAD ~ providers} to the system, or to substitute a new provider for {TAIL ~ an existing provider}, without changing or recompiling any other component in the system 
With the present invention , it is possible to add { HEAD ~ providers } to the system , or to substitute a new provider for { TAIL ~ an existing provider } , without changing or recompiling any other component in the system
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH