// Copyright (c) 2005  Stanford University (USA).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.2-branch/Kinetic_data_structures/include/CGAL/Kinetic/Multi_listener.h $
// $Id: Multi_listener.h 29334 2006-03-10 00:00:09Z drussel $
// 
//
// Author(s)     : Daniel Russel <drussel@alumni.princeton.edu>

#ifndef CGAL_TOOLS_MULTI_LISTENER_BASE_H
#define CGAL_TOOLS_MULTI_LISTENER_BASE_H
#include <CGAL/basic.h>
CGAL_KINETIC_BEGIN_NAMESPACE

//! This is a variant of Listener which supports more than one object receiving notifications
/*!
  See Listener for full documentation.

  In contrast to listener, this can be copied.
*/
template <class Interface>
class Multi_listener: public Interface
{
  typedef Multi_listener<Interface> This;
public:
  typedef typename Interface::Notifier_handle::element_type Notifier;

  Multi_listener(typename Interface::Notifier_handle &nh): h_(nh) {
    h_->new_listener(this);
  }

  Multi_listener(Notifier* nh): h_(nh) {
    h_->new_listener(this);
  }

  Multi_listener(){}

  virtual ~Multi_listener() {
    h_->delete_listener(this);
  }

  typename Interface::Notifier_handle::element_type* notifier() {
    return h_.get();
  }

  const typename Interface::Notifier_handle::element_type* notifier() const
  {

    return h_.get();
  }

  virtual void new_notification(typename Interface::Notification_type nt)=0;


  Multi_listener(const This &o) {
    h_= o.h_;
    h_->new_listener(this);
  }

  const This& operator=(const This &o) {
    h_= o.h_;
    h_->new_listener(this);
    return *this;
  }
protected:
  typename Interface::Notifier_handle h_;
};

CGAL_KINETIC_END_NAMESPACE
#endif