/////////////////////////////////////////////////////////////////////////
//  interfaceClient.cpp - Demonstrate Creation and proper use of       //
//                        Dynamic Link Libraries (DLLs)                //
//                                                                     //
//  Language:    Visual C++, ver 7.0                                   //
//  Platform:    Dell Dimension 8100, Windows 2000, SP 2.0             //
//  Application: Demonstration for CSE775 - Distributed Objects        //
//  Author:      Jim Fawcett, CST 2-187, Syracuse University           //
//               (315) 443-3948, jfawcett@twcny.rr.com                 //
/////////////////////////////////////////////////////////////////////////
/*
    Operations:
    ===========
    This workspace contains six modules:
    1. DemoDll (implemented by this module)
       - demonstrates creation of basic dll, exporting a class
         and global functions
    2. RevisedDemoDll
       - changes the implementation of DemoDll but keeps its
         interface and semantics.
    3. dllClient
       - uses both DemoDll.dll and RevisedDemoDll.dll
       - use of DemoDll.dll is successful
       - use of RevisedDemoDll crashes because dll was modified
         but client was not, and client was welded to the dll's
         implementation.
    4. DemoInterface
       - demonstrates how to build a dll that does not require
         a client to bind to its implementation by providing
         an interface (abstract class) with a creational function.
    5. RevisedDemoInterface
       - changes the implementation of DemoInterface but keeps
         its interface and semantics.
    6. interfaceClient
       - uses both DemoInterface and RevisedDemoInterface
         successfully.

//

       Example of what does not work:
       
         DemoDll and RevisedDemoDll use the same class and 
         function syntax but different implementations.
         Since dllClient binds directly to CDemoDll, it
         cannont survive changes to the CDemoDll imple-
         mentation that result in different object sizes.

           +-----------+      +----------+
           | dllClient |----->| CDemoDll |
           +-----------+      +----------+

                           1st version in DemoDll
                           2nd version in RevisedDemoDll

       Example of what does work:

         DemoInterface and RevisedDemoInterface use the same
         class and function syntax.  Since only the CDemoDll
         implementing class changes the interfaceClient works 
         successfully with both.

           +-----------------+      +----------------+
           | interfaceClient |----->| CDemoInterface |
           +-----------------+      +----------------+
                                           / \
                                            |
                                            |
                                       +----------+      
                                       | CDemoDll |
                                       +----------+

                                   1st version in DemoInterface
                                   2nd version in RevisedDemoInterface

*/
//
/////////////////////////////////////////////////////////////////////////
//  Build Processes                                                    //
/////////////////////////////////////////////////////////////////////////
//  DemoDll:                                                           //
//    Required Files:                                                  //
//      DemoDll.h, DemoDll.cpp, stdafx.h, stdafx.cpp                   //
//    compiler command:                                                //
//      devenv DemoDll.vcproj /make /rebuild                           //
/////////////////////////////////////////////////////////////////////////
//  RevisedDemoDll:                                                    //
//    Required Files:                                                  //
//      RevisedDemoDll.h, RevisedDemoDll.cpp, stdafx.h, stdafx.cpp     //
//    compiler command:                                                //
//      devenv RevisedDemoDll.vcproj /make /rebuild                    //
/////////////////////////////////////////////////////////////////////////
//  dllClient     :                                                    //
//    Required Files:                                                  //
//      dllClient.cpp, stdafx.h, stdafx.cpp, DemoDll.dll, DemoDll.lib  //
//    compiler command:                                                //
//      devenv dllClient.vcproj /make /rebuild                         //
/////////////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////////////////
//  DemoInterface:                                                     //
//    Required Files:                                                  //
//      DemoInterface.h, DemoInterface.cpp, stdafx.h, stdafx.cpp       //
//    compiler command:                                                //
//      devenv DemoInterface.vcproj /make /rebuild                     //
/////////////////////////////////////////////////////////////////////////
//  RevisedDemoInterface:                                              //
//    Required Files:                                                  //
//      RevisedDemoInterface.h, RevisedDemoInterface.cpp,              //
//      stdafx.h, stdafx.cpp                                           //
//    compiler command:                                                //
//      devenv RevisedDemoInterface.vcproj /make /rebuild              //
/////////////////////////////////////////////////////////////////////////
//  interfaceClient:                                                   //
//    Required Files:                                                  //
//      interfaceClient.cpp, stdafx.h, stdafx.cpp,                     //
//      DemoInterface.dll, DemoInterface.lib                           //
//    compiler command:                                                //
//      devenv interfaceClient.vcproj /make /rebuild                   //
/////////////////////////////////////////////////////////////////////////

//
#include "stdafx.h"
///////////////////////////////////////////////////////////////////////
//  DemoInterface.cpp - Demonstrate Creation and proper use of       //
//                      Dynamic Link Libraries (DLLs)                //
//                                                                   //
//  Language:    Visual C++, ver 7.0                                 //
//  Platform:    Dell Dimension 8100, Windows 2000, SP 2.0           //
//  Application: Demonstration for CSE775 - Distributed Objects      //
//  Author:      Jim Fawcett, CST 2-187, Syracuse University         //
//               (315) 443-3948, jfawcett@twcny.rr.com               //
///////////////////////////////////////////////////////////////////////
/*
    Operations:
    ===========
    This workspace contains six modules:
    1. DemoDll (implemented by this module)
       - demonstrates creation of basic dll, exporting a class
         and global functions
    2. RevisedDemoDll
       - changes the implementation of DemoDll but keeps its
         interface and semantics.
    3. dllClient
       - uses both DemoDll.dll and RevisedDemoDll.dll
       - use of DemoDll.dll is successful
       - use of RevisedDemoDll crashes because dll was modified
         but client was not, and client was welded to the dll's
         implementation.
    4. DemoInterface
       - demonstrates how to build a dll that does not require
         a client to bind to its implementation by providing
         an interface (abstract class) with a creational function.
    5. RevisedDemoInterface
       - changes the implementation of DemoInterface but keeps
         its interface and semantics.
    6. interfaceClient
       - uses both DemoInterface and RevisedDemoInterface
         successfully.
*/
//
#include <iostream>
#include "DemoInterface.h"
using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
  cout << "\n  Demonstrate use of DLL Through Interface with same exports "
       << "\n ============================================================\n";

  cout << "\n  current directory is:           " << GetDir();

  CDemoInterface *pInterface = CDemoInterface::CreateDemoDll();
  pInterface->setDir("c:/temp");
  cout << "\n  directory has been set to:      " << pInterface->getDir();
  pInterface->restore();
  cout << "\n  directory has been restored to: " << pInterface->getDir();
  //
  //  The following statements fail to link because the interface-based dll
  //  no-longer exports the CDemoDll class definition.  We can turn this into
  //  a compile-time failure - a good thing -  by moving the CDemoDll class 
  //  declaration into the DemoInterface.cpp and RevisedDemoInterface.cpp
  //  files, keeping just the interface declaration in the header file.
  //
  //    CDemoDll cd;
  //    CDemoDll *pCd = new CDemoDll();
  //
  cout << "\n\n";
	return 0;
}