Utilities/interface/Presence.h

0001 #ifndef FWCore_Utilities_Presence_h
0002 #define FWCore_Utilities_Presence_h
0003
0004 // -*- C++ -*-
0005
0006 /*
0007   An interface class defining a presence.  A presence is an object that an
0008   executable can instantiate at an early time in order to initialize
0009   various things.  The destructor
0010   takes action to terminate the artifacts of the run() method.
0011
0012   The prototypical use of this is to establish the MessageServicePresence.
0013   That class appears in MessageService, which is a plugin.  By using this
0014   abstract class, we can arrange that cmsRun, in Framework, has no link
0015   dependency on MessageService.  Instead, the MessageServicePresence is
0016   dynamically (run-time) loaded.
0017 */
0018
0019 namespace edm {
0020
0021   class Presence {
0022   public:
0023     Presence() {}
0024     virtual ~Presence() = 0;
0025   };
0026 }  // namespace edm
0027 #endif  // FWCore_Utilities_Presence_h