#ifndef KTJET_KTDISTANCEINTERFACE_H
#define KTJET_KTDISTANCEINTERFACE_H

#include <string>
#include "KtJet/KtUtil.h"

namespace KtJet {
  /**
   *  Interface class to calculate Kt for jets and pairs.  
   
   @author J.Butterworth J.Couchman B.Cox B.Waugh
  */
  class KtLorentzVector;
  class KtDistance {
  public:
    /** virtual destructor needed */
    virtual ~KtDistance() {}
    /** Jet Kt */
    virtual KtFloat operator()(const KtLorentzVector &) const = 0;
    /** Pair Kt */
    virtual KtFloat operator()(const KtLorentzVector &, const KtLorentzVector &) const = 0;
    /** Name of scheme */
    virtual std::string name() const = 0;
  };
  
}// end of namespace

#endif