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// $Id: G4StackManager.hh,v 1.12 2006/06/29 18:09:07 gunter Exp $
// GEANT4 tag $Name: geant4-09-02-ref-02 $
//
//


#ifndef G4StackManager_h
#define G4StackManager_h 1

#include "G4UserStackingAction.hh"
#include "G4StackedTrack.hh"
#include "G4TrackStack.hh"
#include "G4ClassificationOfNewTrack.hh"
#include "G4Track.hh"
#include "G4TrackStatus.hh"
#include "globals.hh"
class G4StackingMessenger;
class G4VTrajectory;

// class description:
//
//  This is the manager class of handling stacks of G4Track objects.
// This class must be a singleton and be constructed by G4EventManager.
// Almost all methods must be invoked exclusively by G4EventManager.
// Especially, some Clear() methods MUST NOT be invoked by the user.
// Event abortion is handled by G4EventManager.
//
//  This G4StackingManager has three stacks, the urgent stack, the
// waiting stack, and the postpone to next event stack. The meanings
// of each stack is descrived in the Geant4 user's manual.
//


class G4StackManager 
{
  public:
      G4StackManager();
      ~G4StackManager();

  private:
      const G4StackManager & operator=
                          (const G4StackManager &right);
      G4int operator==(const G4StackManager &right) const;
      G4int operator!=(const G4StackManager &right) const;

  public:
      G4int PushOneTrack(G4Track *newTrack, G4VTrajectory *newTrajectory = 0);
      G4Track * PopNextTrack(G4VTrajectory**newTrajectory);
      G4int PrepareNewEvent();

  public: // with description
      void ReClassify();
      //  Send all tracks stored in the Urgent stack one by one to 
      // the user's concrete ClassifyNewTrack() method. This method
      // can be invoked from the user's G4UserStackingAction concrete
      // class, especially fron its NewStage() method. Be aware that
      // when the urgent stack becomes empty, all tracks in the waiting
      // stack are send to the urgent stack and then the user's NewStage()
      // method is invoked.

      void SetNumberOfAdditionalWaitingStacks(G4int iAdd);
      //  Set the number of additional (optional) waiting stacks.
      // This method must be invoked at PreInit, Init or Idle states.
      // Once the user set the number of additional waiting stacks,
      // he/she can use the corresponding ENUM in G4ClassificationOfNewTrack.
      // The user should invoke G4RunManager::SetNumberOfAdditionalWaitingStacks
      // method, which invokes this method.

      void TransferStackedTracks(G4ClassificationOfNewTrack origin, G4ClassificationOfNewTrack destination);
      //  Transfter all stacked tracks from the origin stack to the destination stack.
      // The destination stack needs not be empty.
      // If the destination is fKill, tracks are deleted.
      // If the origin is fKill, nothing happen.

      void TransferOneStackedTrack(G4ClassificationOfNewTrack origin, G4ClassificationOfNewTrack destination);
      //  Transfter one stacked track from the origin stack to the destination stack.
      // The transfered track is the one which came last to the origin stack.
      // The destination stack needs not be empty.
      // If the destination is fKill, the track is deleted.
      // If the origin is fKill, nothing happen.

  private:
      G4UserStackingAction * userStackingAction;
      G4int verboseLevel;
      G4TrackStack * urgentStack;
      G4TrackStack * waitingStack;
      G4TrackStack * postponeStack;
      G4StackingMessenger* theMessenger;
      std::vector<G4TrackStack*> additionalWaitingStacks;
      G4int numberOfAdditionalWaitingStacks;

  public:
      inline void clear()
      { 
        ClearUrgentStack();
        ClearWaitingStack();
        for(int i=1;i<=numberOfAdditionalWaitingStacks;i++) {ClearWaitingStack(i);}
      }
      inline void ClearUrgentStack()
      { urgentStack->clear(); }
      inline void ClearWaitingStack(int i=0)
      {
        if(i==0) {
          waitingStack->clear(); 
        } else {
          if(i<=numberOfAdditionalWaitingStacks) additionalWaitingStacks[i-1]->clear();
        }
      }
      inline void ClearPostponeStack()
      { postponeStack->clear(); }
      inline G4int GetNTotalTrack() const
      { int n = urgentStack->GetNTrack() + waitingStack->GetNTrack() + postponeStack->GetNTrack();
        for(int i=1;i<=numberOfAdditionalWaitingStacks;i++) {n += additionalWaitingStacks[i-1]->GetNTrack();}
        return n;
      }
      inline G4int GetNUrgentTrack() const
      { return urgentStack->GetNTrack(); }
      inline G4int GetNWaitingTrack(int i=0) const
      { if(i==0) { return waitingStack->GetNTrack(); }
        else {
         if(i<=numberOfAdditionalWaitingStacks) { return additionalWaitingStacks[i-1]->GetNTrack();}
        }
        return 0;
      }
      inline G4int GetNPostponedTrack() const
      { return postponeStack->GetNTrack(); }
      inline void SetVerboseLevel( G4int const value )
      { verboseLevel = value; }
      inline void SetUserStackingAction(G4UserStackingAction* value)
      { 
	userStackingAction = value;
        if(userStackingAction) userStackingAction->SetStackManager(this);
      }

  private:
      inline G4ClassificationOfNewTrack 
      DefaultClassification(G4Track *aTrack)
      { 
        G4ClassificationOfNewTrack classification = fUrgent;
        if( aTrack->GetTrackStatus() == fPostponeToNextEvent )
        { classification = fPostpone; }
        return classification;
      }
};

#endif