【デザインパターン】プロキシ

Proxy.cpp

/*
   複合パターン のサンプルプログラム
   
   説明
   本人オブジェクトの代わりに、代理人オブジェクトが一部の仕事をこなす方式
   
  
*/
#include <iostream>
using namespace std;

class File
{
  public:
    virtual void draw() = 0;
    
    string getFileName()
    {
        return m_fileName;
    }
    
    protected:
      string m_fileName;
};

class NpcInfoFile : public File
{
    public:
    NpcInfoFile(string fileName)
    {
        this->m_fileName = fileName;
    }
    
    void draw() override
    {
        cout << "NpcInfo " + m_fileName + "\n";
    }
};

class NpcInfoFileProxy: public File
{
    public:
      NpcInfoFileProxy(string _fileName)
      {
          this->m_fileName = _fileName;
      }
      void draw() override
      {
          getFile().draw();
      }
    private:
      NpcInfoFile getFile()
      {
          if(m_pNpcInfoFile != nullptr)
          {
              return *m_pNpcInfoFile;
          }
          m_pNpcInfoFile = new NpcInfoFile(m_fileName);
          return *m_pNpcInfoFile;
      }
      NpcInfoFile* m_pNpcInfoFile = nullptr;
};

int main(void){
    // Your code here!
    NpcInfoFileProxy _npcInfoFileProxy("npcInfo.txt");
    string fileName = _npcInfoFileProxy.getFileName();
    _npcInfoFileProxy.draw();
}