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general/SObservable.h

Go to the documentation of this file.

/* #start# ***********************************************************

           Scheduling Simulator
        Lehrstuhl f"ur Effiziente Algorithmen
           Technische Universit"at M"unchen

 File    : $Id: SObservable.h,v 1.4 2003/01/08 18:57:11 meierb Exp $

 Purpose : the observable part in the classical observer-pattern
           CAUTION: since the observer-mechanism is somewhat implicit
           the following policy should be obeyed under all
     circumstances in order to avoid confusion:
     events are generated exactly when the state changes (in the
     same method where the state of an object changes).

 RCS-Log:
 $Log: SObservable.h,v $
 Revision 1.4  2003/01/08 18:57:11  meierb
 added randomized release times

 Revision 1.1.1.1  2002/12/02 22:26:19  meierb
 my_schedule

 Revision 1.2  2002/11/13 18:42:59  taeubig
 Adaptation of the compare() function for LEDA 4.4 (namespace leda)

 Revision 1.1  2002/08/29 12:59:58  taeubig
 Added the sources

 Revision 1.12  2000/05/24 12:28:49  taeubig
 New compiler (gcc-2.95) and new Qt (2.1)
 Replaced "list" by "leda_list" etc.

 Revision 1.11  2000/01/11 17:26:11  zoidl
 added javadoc comments

 Revision 1.10  1999/11/19 16:10:50  hall
 changed SObserver::update( SEvent & ) to ...( const SEvent & )

 Revision 1.9  1999/11/19 14:54:47  hall
 a nice destructor added to SObserver

 Revision 1.8  1999/08/05 13:02:38  schickin
 redesign: event list for algorithm is generated by logger now

 Revision 1.7  1999/08/05 08:47:50  schickin
 purpose of important classes noted in the header-files

 Revision 1.6  1999/04/27 13:38:51  schickin
 well folks, that's the first demo version that really runs 8-)

 Revision 1.5  1999/02/10 15:53:26  hall
 TypeInfo, Observer works

 Revision 1.4  1999/02/10  10:50:43  schickin
 main loop for simulation added
 
 Revision 1.3  1999/01/29 10:03:29  schickin
 Project-Headers added.

 * #end# ************************************************************* */

#ifndef SOBSERVABLE_H
#define SOBSERVABLE_H

// system header files
#include <cassert>

#include <LEDA/list.h>

// project header files
#include "SObserver.h"
#include "SEvent.h"


// -----------------------------------------------------------------------
class SObservable {
public:
  SObservable() : _observers() {};
  
  SObservable(const SObservable& rObs);
  
  virtual ~SObservable();
  
  void addObserver(SObserver &obs);
  void deleteObserver(SObserver &obs);

  void notifyObservers(const SEvent& event);

private:
  leda_list<SObserver *> _observers;
};
// -----------------------------------------------------------------------

// -----------------------------------------------------------------------
inline
SObservable::SObservable(const SObservable& rObs) {
  // don't copy observables which are being observed
  assert(_observers.size() == 0);
}
// -----------------------------------------------------------------------
inline
SObservable::~SObservable() {
  SObserver *pObs;

  // perhaps send a SObsEvent message here

  forall(pObs, _observers) {
    pObs->deleteObservable(*this);
  }
}
// -----------------------------------------------------------------------
inline
void SObservable::addObserver(SObserver &obs) {
  _observers.append(&obs);
  obs.addObservable(*this);
}
// -----------------------------------------------------------------------
inline
void SObservable::deleteObserver(SObserver &obs) {
  _observers.remove(&obs);
  obs.deleteObservable(*this);
}
// -----------------------------------------------------------------------
inline
void SObservable::notifyObservers(const SEvent& event){
  SObserver *pObs;

  forall(pObs, _observers) {
    pObs->update(event);
  }
}
// -----------------------------------------------------------------------

// -----------------------------------------------------------------------
#if __LEDA__ >= 440
namespace leda {
#endif
inline
int compare(SObservable *const & obs1, SObservable *const & obs2) {
  if( obs1 < obs2 )
    return -1;
  else if( obs1 > obs2 )
    return 1;
  else
    return 0;
}
#if __LEDA__ >= 440
}
#endif
// -----------------------------------------------------------------------

#endif //SOBSERVABLE_H

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