ColCOWS_EventHandler.hh

//===========================================================================//
//    
//    Description: interface for user defined event handling classes
//    Filename: colcows/ColCOWS_EventHandler.hh
//    Authors: Michael Dussere and Aurélien Esnard
//    
//===========================================================================//
//    
//    Copyright (C) 2003 INRIA and CNRS
//    
//    This library is free software; 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; either
//    version 2.1 of the License, or (at your option) any later version.
//    
//    This library 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
//    Lesser General Public License for more details.
//    
//    You should have received a copy of the GNU Lesser General Public
//    License along with this library; if not, write to the Free Software
//    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//    
//===========================================================================//

#ifndef __COLCOWS_EVENT_HANDLER_HH__
#define __COLCOWS_EVENT_HANDLER_HH__

//---------------------------------------------------------------------------//
#include "ColCOWS_Include.hh"
#include "ColCOWS_Debug.hh" 
//---------------------------------------------------------------------------//

namespace ColCOWS {
  class EventHandlerManager;
  class Node;
}

__COLCOWS_BEGIN__

//! ColCOWS event handler
/** 
 * The EventHandler allows the user to catch and react to events of workspace life-cycle
 * (activation, connection, disconnection). 
 *
 * The user must declare a class inheriting from EventHandler and implement the event methods
 * called by the ColCOWS nodes. Then he must register his event handler to the node with
 * Node::setEventHandler( ... ).
 *
 * \todo Allow several event handlers to be connected on one workspace
 */
class EventHandler
{

  //================================================//
  //=========== class standard interface ===========//
public:
  friend class EventHandlerManager;

  //! constructor
  EventHandler(): _key(0) {};
  
  //! destructor
  virtual ~EventHandler() {};

  //============================================//
  //=========== protected  interface ===========//
protected:

  //! treatment on the activation of the workspace
  virtual void onActivation() {}

  //! treatment on the deactivation of the workspace
  virtual void onDeactivation() {}

  //! treatment on the connection of a workspace
  virtual void onConnection( unsigned long num_connection, bool initiator ) {}

  //! treatment on a disconnection 
  virtual void onDisconnection( unsigned long num_connection ) {}

  //========================================//
  //============== Accessors ===============//
public:

  //! get key of this event handler in its event handler manager ( 0 => not registred to an event handler manager )
  inline unsigned int getKey() const { return _key; }

  //! set key of this event handler in its event handler manager ( 0 => not registred to an event handler manager )
  inline void setKey( unsigned int key) { _key = key; }

  //! get event handler manager pointer
  inline EventHandlerManager * getEventHandlerManager( ) const { return _event_handler_manager; }

  //! set event handler manager pointer
  inline void setEventHandlerManager( EventHandlerManager * event_handler_manager) { _event_handler_manager = event_handler_manager; }

  //! get ColCOWS Node pointer
  Node * getColCOWSNode( ) const;

protected:
  //! associated EventHandlerManager
  EventHandlerManager * _event_handler_manager;

  //! key in the event handler manager
  unsigned int _key;
};

__COLCOWS_END__

#endif // __COLCOWS_EVENT_HANDLER_HH__

// EOF

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