TVirtualTreePlayer.cxx

Go to the documentation of this file.

// @(#)root/tree:$Id$
// Author: Rene Brun   30/08/99
 
/*************************************************************************
 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
/** \class TVirtualTreePlayer
\ingroup tree
 
Abstract base class defining the interface for the plugins that
implement Draw, Scan, Process, MakeProxy, etc. for a TTree object.
See the individual documentations in TTree.
*/
 
#include "TROOT.h"
#include "TVirtualTreePlayer.h"
#include "TPluginManager.h"
#include "TClass.h"
 
TClass              *TVirtualTreePlayer::fgPlayer  = nullptr;
TVirtualTreePlayer  *TVirtualTreePlayer::fgCurrent = nullptr;
 
ClassImp(TVirtualTreePlayer);
 
////////////////////////////////////////////////////////////////////////////////
/// Static function returning a pointer to a Tree player.
/// The player will process the specified obj. If the Tree player
/// does not exist a default player is created.
 
TVirtualTreePlayer *TVirtualTreePlayer::TreePlayer(TTree *obj)
{
   // if no player set yet,  create a default painter via the PluginManager
   if (!fgPlayer) {
      TPluginHandler *h;
      if ((h = gROOT->GetPluginManager()->FindHandler("TVirtualTreePlayer"))) {
         if (h->LoadPlugin() == -1)
            return nullptr;
         TVirtualTreePlayer::SetPlayer(h->GetClass());
      }
      if (!fgPlayer) return nullptr;
   }
 
   //create an instance of the Tree player
   TVirtualTreePlayer *p = (TVirtualTreePlayer*)fgPlayer->New();
   if (p) p->SetTree(obj);
   fgCurrent = p;
   return p;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Common destructor.
 
TVirtualTreePlayer::~TVirtualTreePlayer()
{
   if (fgCurrent==this) {
      // Make sure fgCurrent does not point to a deleted player.
      fgCurrent=nullptr;
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Static function: return the current player (if any)
 
TVirtualTreePlayer *TVirtualTreePlayer::GetCurrentPlayer()
{
   return fgCurrent;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Static function to set an alternative Tree player.
 
void TVirtualTreePlayer::SetPlayer(const char *player)
{
   fgPlayer = TClass::GetClass(player);
}