#ifndef MT2Q7_H
#define MT2Q7_H
///////////////////////////////////////////////////////////////
// MT2Q7.h - Callback                                        //
//                                                           //
// Jim Fawcett, CSE687 - Object Oriented Design, Spring 2012 //
///////////////////////////////////////////////////////////////

#include <iostream>
#include <string>
#include <vector>

class Widget
{
public:
  void f(const std::string& s)
  {
    std::cout << "\n  been called with string \"" << s.c_str() << "\"";
  }
};

template<typename T>
class Invoker
{
public:
  typedef void (T::*fptr)(const std::string&);  // first important part
  typedef std::pair<T*,fptr> elem;
  
  void subscribe(T* pT, fptr f)  // client must pass object ref and func ptr
  {
    elem e;
    e.first = pT;
    e.second = f;
    commands.push_back(e);
  }
  void invoke(const std::string& s)
  {
    for(size_t i=0; i<commands.size(); ++i)
    {
      elem e = commands[i];
      T t = *e.first;
      fptr fp = e.second;
      (t.*fp)(s);             // second important part
    }
  }
private:
  std::vector<elem> commands;
};
#endif