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SubjectObserver.h

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// SubjectObserver.h: interface for the Subject and Observer classes
//

// Adapted from the Subject-Observer section of 
// "Design Patterns, Elements of Reusable Object-Oriented Software"
// by E. Gamma, R. Helm, R. Johnson, and J. Vlissides, 
// Addison Wesley, Massachusetts, 1995
// ISBN 0-201-63361-2


#ifndef OBSERVER_H
#define OBSERVER_H

#ifndef SWIG
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#endif

#include <list>
// #include "Introspective.h"

class Subject;

// class Observer : public Introspective
class Observer
{
public:
        virtual ~Observer() {};
        virtual void Update(Subject *theChangedSubject) = 0;

protected:
        Observer()
        {
/*              // Drew's registration with MOP: allows Get and Set functions to be called
                // from dialog boxes, in serialization, and for copying
                if (NotYetRegistered("Observer",typeid(*this))) 
                {
                        AddType("Observer",typeid(*this));
                } */
        } 
};

class Subject  
{
public:
        virtual ~Subject() 
        {
                delete _observers;
        }
        virtual void  Attach(Observer* o) 
        {
                _observers->push_back(o);
        }
        virtual void Detach(Observer* o) 
        {
                _observers->remove(o);
        }
        virtual void Notify() 
        {
                std::list<Observer*>::iterator i = _observers->begin();
                while (i != _observers->end()) 
                {
                        (*i)->Update(this);
                        i++;
                }
        }

protected:
#ifndef SWIG // XXX SWIG doesn't support standard template libraries
        Subject() 
        {
                _observers = new std::list<Observer*>;
        }
#endif // SWIG
private:
#ifndef SWIG // XXX SWIG doesn't support standard template libraries
        std::list<Observer*> *_observers;
#endif // SWIG
};

#endif // !defined(OBSERVER_H)

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