// $Id$
//-----------------------------------------------------------------------
//       The GSI Online Offline Object Oriented (Go4) Project
//         Experiment Data Processing at EE department, GSI
//-----------------------------------------------------------------------
// Copyright (C) 2000- GSI Helmholtzzentrum fuer Schwerionenforschung GmbH
//                     Planckstr. 1, 64291 Darmstadt, Germany
// Contact:            http://go4.gsi.de
//-----------------------------------------------------------------------
// This software can be used under the license agreements as stated
// in Go4License.txt file which is part of the distribution.
//-----------------------------------------------------------------------

#ifndef TGO4TREESOURCE_H
#define TGO4TREESOURCE_H

#include "TGo4EventSource.h"

class TGo4TreeSourceParameter;
class TGo4MainTree;
class TGo4EventElement;
class TBranch;
class TTree;

/**
 * @brief Raw event source which reads entries from a root TTree.
 * @details We use one single tree for all generations of events,
 * which is kept by the go4 maintree class.
 * @ingroup go4_event
 * @author J. Adamczewski
 * @since 1/2001
 */
class TGo4TreeSource : public TGo4EventSource {
  public:
    TGo4TreeSource();

    TGo4TreeSource(const char *name);

    virtual ~TGo4TreeSource();

    TGo4TreeSource(TGo4TreeSourceParameter *par);

    /** Fill the destination event dest from the tree.
      * If end of tree is reached, the current event counter
      * is reset and a kFALSE value is returned. */
    Bool_t BuildEvent(TGo4EventElement *dest) override;

  private:

    /** Reference to external tree singleton wrapper instance.
      * Is initialized once at the start and used to access
      * the singleton member functions. */
    TGo4MainTree *fxSingletonTree{nullptr}; //!

    /** Reference to external root tree singleton. */
    TTree *fxTree{nullptr};//!

    /** The branch representing our source. */
    TBranch *fxBranch{nullptr}; //!

    Int_t Open();

  ClassDefOverride(TGo4TreeSource,1)
};

#endif //TGO4TREESOURCE_H