//-----------------------------------------------------------------------------
//  15 Dec 2000 P.Murat: abstract interface to the extrapolator
//-----------------------------------------------------------------------------

#ifndef Stntuple_alg_TExtrapolator_hh
#define Stntuple_alg_TExtrapolator_hh

#include "TNamed.h"

class TTrajectoryPoint;

class TExtrapolator : public TNamed {
public:
//_____________________________________________________________________________
//  functions
//_____________________________________________________________________________
public:

  TExtrapolator();
  virtual ~TExtrapolator();

  virtual Int_t Init(Double_t* xyz, 
		     Double_t* mom, 
		     Int_t     charge, 
		     Int_t     mode) { return 0; }

  virtual void GetFinalResults(Double_t*  xyz, 
			       Double_t*  mom, 
			       Double_t&  ptot) {};

  virtual int SwimToPathLength(Double_t s) { return 0; }

					// Swim to a particular R.     

  virtual int SwimToR(Double_t r) { return 0; }
//-----------------------------------------------------------------------------
// extrapolate particle to a set of ordered Z planes and return a 
// set of the trajectory points at given Z's
//-----------------------------------------------------------------------------
  virtual int SwimToZ (int               Charge,
		       int               N     , 
		       const Double_t*   Z     , 
		       TTrajectoryPoint* P     ) 
  { return 0; }

					// swim to a particular x ( CMP)

  virtual int SwimToX(float) { return 0; }

					// swim to a particular y ( CMP )

  virtual int SwimToY(float) { return 0; }
//-----------------------------------------------------------------------------
// extrapolate particle to a set of ordered radii and return a set of
// trajectory points, corresponding to these radii
//-----------------------------------------------------------------------------
  virtual int SwimToCmu(int               charge,
			int               n, 
			const Double_t*   radius, 
			TTrajectoryPoint* p)=0;

  // swim to CCAL or PCAL
  virtual int SwimToCal(TTrajectoryPoint* Point, int Charge) {return 0;}

  ClassDef(TExtrapolator,0)
};

#endif