Proxy_Class.cpp

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#include <iostream>
#include <memory>
 
#include "helpers/formatstring.h"
 
#include "Proxy_Class.h"
 
namespace Proxy_Class_Private
{
    // For the purposes of this example, this namespace encapsulates the real
    // class and proxy class to hide them from the rest of the example
    // program.  In a real program, the real class would be in its own
    // assembly and separate from the proxy class.
 
 
    class Real_Class : public DesignPatternExamples_cpp::IWorkByProxy
    {
    public:
        // Implementation of the IWorkByProxy interface
        std::string DoWork(std::string someArgument)
        {
            return Helpers::formatstring("Real class received '%s'", someArgument.c_str());
        }
    };
 
    //====================================================================
    //====================================================================
 
 
    class Proxy_Class : public DesignPatternExamples_cpp::IWorkByProxy
    {
    private:
        std::unique_ptr<DesignPatternExamples_cpp::IWorkByProxy> _realClassInstance;
 
        DesignPatternExamples_cpp::IWorkByProxy* _GetRealClass()
        {
            if (_realClassInstance == nullptr)
            {
                std::cout << "  --> Creating instance of real class..." << std::endl;
                _realClassInstance = std::make_unique<Real_Class>();
            }
            return _realClassInstance.get();
        }
 
 
    public:
        // Implementation of the IWorkByProxy interface
 
        std::string DoWork(std::string someArgument)
        {
            std::cout << "  --> proxy class DoWork() in" << std::endl;
            DesignPatternExamples_cpp::IWorkByProxy* realClass = _GetRealClass();
            std::cout << "  --> Forwarding DoWork() call to real class..." << std::endl;
            return realClass->DoWork(someArgument);
        }
    };
 
} // end Proxy_Class_Private namespace
 
 
//============================================================================
//============================================================================
 
 
namespace DesignPatternExamples_cpp
{
    std::unique_ptr<IWorkByProxy> Proxy_Classes_Container::CreateProxy()
    {
        std::cout << "  --> Creating instance of proxy class..." << std::endl;
        return std::make_unique<Proxy_Class_Private::Proxy_Class>();
    }
 
} // end namespace