G4PhysicsConstructorFactory.hh

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#ifndef G4PhysicsConstructorFactory_h
#define G4PhysicsConstructorFactory_h 1


#include "globals.hh"
#include "G4PhysicsConstructorRegistry.hh"
#include "G4VPhysicsConstructor.hh"

class G4VBasePhysConstrFactory
{

public:

  virtual G4VPhysicsConstructor* Instantiate() = 0;

};


template <typename T> class G4PhysicsConstructorFactory : public G4VBasePhysConstrFactory
{
public:
  
  G4PhysicsConstructorFactory(const G4String& name)
  {
    G4PhysicsConstructorRegistry::Instance()->AddFactory(name, this);
  }
  
  virtual G4VPhysicsConstructor* Instantiate() 
  {
    return new T();
  }
};


#define G4_DECLARE_PHYSCONSTR_FACTORY(physics_constructor) \
  const G4PhysicsConstructorFactory<physics_constructor>& physics_constructor##Factory = G4PhysicsConstructorFactory<physics_constructor>(#physics_constructor)

// support for phys constructors defined within a namespace
// a bit tricky due to cpp macro expansion and the use of "::"
// use  G4_DECLARE_PHYSCONSTR_FACTORY_NS( myns::MyProc, myns, MyProc );
#define G4_DECLARE_PHYSCONSTR_FACTORY_NS( physics_constructor, nsname, pcbase )  \
  namespace nsname { \
    const G4PhysicsConstructorFactory<physics_constructor>& pcbase##Factory = G4PhysicsConstructorFactory<physics_constructor>(#physics_constructor); \
  } \
  typedef int xyzzy__LINE__
  // eat trailing semicolon using silly typedef

// REFERENCE (rather than DECLARE) when the physics constructor if it is part
// of a static library.  No need to include the header (DECLARE needs this
// to build the code), we just need to make a reference in order to pull
// the compilation unit static variable from the library and cause it
// to be initialized (and thus self-register)

#define G4_REFERENCE_PHYSCONSTR_FACTORY(physics_constructor) \
  class physics_constructor; \
  extern const G4PhysicsConstructorFactory<physics_constructor>& physics_constructor##Factory; \
  const G4PhysicsConstructorFactory<physics_constructor>& physics_constructor##FactoryRef = physics_constructor##Factory

#define G4_REFERENCE_PHYSCONSTR_FACTORY_NS( physics_constructor, nsname, pcbase ) \
  namespace nsname { \
    class pcbase; \
    extern const G4PhysicsConstructorFactory<physics_constructor>& pcbase##Factory; \
    const G4PhysicsConstructorFactory<physics_constructor>& pcbase##FactoryRef = pcbase##Factory; \
  } \
  typedef int xyzzy__LINE__
  // eat trailing semicolon using silly typedef

#endif