// RecorderBase.hh
// 1-Sep-1999 Bill Seligman

// This is an abstract base class to be used with Geant 4.0.1 (and
// possibly higher, if the User classes don't change).  

// The concept of a Recorder object is that it records the activities of
// Geant in a manner that is useful to a physicist.  Perhaps this record
// takes the form of histograms, or ntuples, or entries in an Objectivity
// database.  This class does not care HOW the information is recorded; it
// abstracts the behavior of a generalized recorder of Geant variables.

// No object should be instantiated from the Recorder class (in fact, any such
// object won't do anything).  The user must define a new class (say, a class 
// that creates histograms) and overload the methods of this class.

// Why do this?  First of all, it keeps all record-keeping in a single class:
// the class that inherits Recorder.  The original Geant documentation suggests
// that recording activities should be split among many different classes
// (initialization in G4UserRunAction, recording in G4UserSteppingAction, etc.).
// If you use a Recorder class, than all the record-keeping details are kept in
// a single class instead of being spread out among many different classes.

// Secondly, by using an abstract Recorder class, you hide the implementation
// details from the rest of Geant.  If you change a couple of histograms, only
// the Recorder-derived class and main() re-compile.  No other class knows or
// cares what or how you record.

// The only time this class (i.e., this header file) changes is if new
// user action classes are added to Geant.

#ifndef RECORDER_BASE_H_
#define RECORDER_BASE_H_

// The following objects are the arguments to the methods
// invoked in the user action classes.  In other words, they
// contain the variables that we are normally able to record
// in Geant.

#include "G4Run.hh"
#include "G4Event.hh"
#include "G4Track.hh"
#include "G4Step.hh"


class RecorderBase {

public:

  virtual ~RecorderBase() {};

  // The following a list of methods that correspond to the available 
  // user action classes in Geant 4.0.1.   In this base class, the
  // methods are defined to do nothing.

  virtual void RecordBeginOfRun(const G4Run*) = 0;
  virtual void RecordEndOfRun(const G4Run*) = 0;
  virtual void RecordBeginOfEvent(const G4Event*) {};
  virtual void RecordEndOfEvent(const G4Event*) {};
  virtual void RecordTrack(const G4Track*) {};
  virtual void RecordStep(const G4Step*) {};

};

#endif