// CandidateLayer.h

#ifndef CandidateLayer_H
#define CandidateLayer_H

// A candidate layer consists of references to a layer, a 
// propagator and a fitter.  It does not handle memory management
// for the corresponding objects.

#include <iosfwd>

namespace trf {

class Layer;
class Propagator;
class AddFitter;
class CandidateLayer;

// output stream
std::ostream& operator<<(std::ostream& stream, const CandidateLayer& cnl);

class CandidateLayer {

private:  // attributes

  // the layer
  const Layer* _player;

  // the propagator
  const Propagator* _pprop;

  // the fitter
  const AddFitter* _pfit;

private:  // methods

  // output stream
  void ostr(std::ostream& stream) const;

public:  // methods

  // default constructor
  CandidateLayer();

  // constructor
  CandidateLayer(const Layer& layer, const Propagator& prop,
                 const AddFitter& fit);

  // destructor
  ~CandidateLayer();

  // return if the data are valid
  // The get routines should not be called if this returns false.
  bool is_valid() const;

  // fetch the layer
  const Layer& get_layer() const { return *_player; };

  // fetch the propagator
  const Propagator& get_propagator() const { return *_pprop; };

  // fetch the fitter
  const AddFitter& get_fitter() const { return *_pfit; };

  // output stream
  friend std::ostream&
  operator<<(std::ostream& stream, const CandidateLayer& cnl);

};

}  // end namespace trf

// equality -- compare addresses
bool operator==(const trf::CandidateLayer& cnl1,
                const trf::CandidateLayer& cnl2);

// inequality
inline
bool operator!=(const trf::CandidateLayer& cnl1,
                const trf::CandidateLayer& cnl2) {
  return ! ( cnl1 == cnl2 );
}

// ordering for STL
bool operator<(const trf::CandidateLayer& cnl1,
               const trf::CandidateLayer& cnl2);

#endif