/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2007 INRIA

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#ifndef HIERARCHICAL_MOBILITY_MODEL_H

#define HIERARCHICAL_MOBILITY_MODEL_H

#include "mobility-model.h"

namespace ns3 {

/**

 * \brief a hierachical mobility model.

 * 

 * This model allows you to specify the position of a

 * child object relative to a parent object.

 */

class HierarchicalMobilityModel : public MobilityModel

{

public:

  static const InterfaceId iid;

  /**

   * \param child the "relative" mobility model

   * \param parent the "reference" mobility model

   */

  HierarchicalMobilityModel (Ptr<MobilityModel> child, Ptr<MobilityModel> parent);

  /**

   * \returns the child mobility model.

   *

   * This allows you to get access to the position of the child

   * relative to its parent.

   */

  Ptr<MobilityModel> GetChild (void) const;

  /**

   * \returns the parent mobility model.

   *

   * This allows you to get access to the position of the 

   * parent mobility model which is used as the reference 

   * position by the child mobility model.

   */

  Ptr<MobilityModel> GetParent (void) const;

private:

  virtual Position DoGet (void) const;

  virtual void DoSet (const Position &position);

  virtual Speed DoGetSpeed (void) const;

  void ParentChanged (const TraceContext &context, Ptr<const MobilityModel> model);

  void ChildChanged (const TraceContext &context, Ptr<const MobilityModel> model);

  Ptr<MobilityModel> m_child;

  Ptr<MobilityModel> m_parent;

};

} // namespace ns3

#endif /* HIERARCHICAL_MOBILITY_MODEL_H */