///////////////////////////////////////////////////////////////////////
//  facade.cpp - implements interface methods                        //
//                                                                   //
//               Demonstrates use of a facade class that implements  //
//               an interface's methods, using services of several   //
//               product classes.                                    //
//                                                                   //
//  Jim Fawcett, CSE687 - Object Oriented Design, Spring 2001        //
///////////////////////////////////////////////////////////////////////
//  Note:                                                            //
//  Notice that this class does not declare the static factory       //
//  method.  This implementation file implements the method          //
//  productAbstraction::createProduct() on behalf of the interface.  //
///////////////////////////////////////////////////////////////////////

#include <iostream>
#include "facade.h"
using namespace std;

productAbstraction *productAbstraction::pPA = NULL;

//----< void constructor >---------------------------------------------

facade::facade() : _request(), _reply() { 

  cout << "\n  constructing facade";

  // tell request how to communicate with reply

  _request.Register(&_reply);
}

//----< destructor >---------------------------------------------------

facade::~facade() { cout << "\n  destroying facade"; }


//----< a method solely implemented by facade >------------------------

void facade::hello() { cout << "\n  Hello.  This is the facade class."; }


//----< reply method delegates its action to replyProduct >------------

std::string facade::reply() { return _reply.reply(); }


//----< request method delegates its action to requestProduct >--------

void facade::request(const std::string &req) { _request.request(req); }


//----< the static factory method that creates everything >------------
//
//  This is a singleton method. Only one facade object can be created.
//
productAbstraction* productAbstraction::createProduct() {
  
  if(pPA == NULL) {
    pPA = new facade;
    return pPA;
  }
  return pPA;
}