Observer.h

/*
    Hyperspace Explorer - vizualizing higher-dimensional geometry
    Copyright (C) 2010  Lene Preuss <lene.preuss@gmail.com>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    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.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

*/

#ifndef OBSERVER_H
#define OBSERVER_H

#include <memory>

template <class Parent> class Observer;


template <class Parent>
class Subject: public Parent {

  public:

    Subject();
    virtual ~Subject();

    virtual void attach(std::shared_ptr< Observer<Parent> > observer);
    virtual void detach(std::shared_ptr< Observer<Parent> > observer);

  protected:

    virtual void notify();

  private:

    class Impl;
    std::shared_ptr<Impl> pImpl_;
};


template <class Parent>
class Observer {

  public:

    virtual ~Observer();

    virtual void update(std::shared_ptr< const Subject<Parent> > changedSubject) = 0;

};

#endif // OBSERVER_H