// @(#)root/roostats:$Id$
// Author: Kyle Cranmer, Lorenzo Moneta, Gregory Schott, Wouter Verkerke
/*************************************************************************
 * Copyright (C) 1995-2008, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

#ifndef ROOSTATS_TestStatistic
#define ROOSTATS_TestStatistic




#include "Rtypes.h"

class RooArgSet;
class RooAbsData;

namespace RooStats {

/** \class RooStats::TestStatistic
    \ingroup Roostats

   TestStatistic is an interface class to provide a facility for construction test statistics
   distributions to the NeymanConstruction class. All the actual samplers inherit from this class.
*/

class TestStatistic {

public:
   //TestStatistic();
   virtual ~TestStatistic() {
   }

   /// Main interface to evaluate the test statistic on a dataset given the
   /// values for the Null Parameters Of Interest.
   virtual Double_t Evaluate(RooAbsData& data, RooArgSet& nullPOI) = 0;

   virtual const TString GetVarName() const = 0;

   /// Defines the sign convention of the test statistic. Overwrite function if necessary.
   virtual  bool PValueIsRightTail(void) const { return true; }

   /// return detailed output: for fits this can be pulls, processing time, ... The returned pointer will not loose validity until another call to Evaluate.
   virtual const RooArgSet* GetDetailedOutput() const { return NULL; }

   /// interface to set conditional observables. If a test statistics needs them it will re-implement this function
   virtual void SetConditionalObservables(const RooArgSet& ) {}

   /// interface to set global observables. If a test statistics needs them it will re-implement this function
   virtual void SetGlobalObservables(const RooArgSet& ) {}

   
protected:
   ClassDef(TestStatistic,1) /// Interface for a TestStatistic
};

} // end namespace RooStats


#endif
