C++设计模式之享元模式

#include <iostream>
#include <map>
#include <vector>
using namespace std;
 
typedef struct pointTag
{
    int x;
    int y;
 
    pointTag(){}
    pointTag(int a, int b)
    {
        x = a;
        y = b;
    }
 
     bool operator <(const pointTag& other) const
     {
         if (x < other.x)
         {
             return true;
         }
         else if (x == other.x)
         {
             return y < other.y;
         }
 
         return false;
     }
}POINT;
 
typedef enum PieceColorTag
{
    BLACK,
    WHITE
}PIECECOLOR;
 
class CPiece
{
public:
    CPiece(PIECECOLOR color) : m_color(color){}
    PIECECOLOR GetColor() { return m_color; }
 
    // Set the external state
    void SetPoint(POINT point) { m_point = point; }
    POINT GetPoint() { return m_point; }
 
protected:
    // Internal state
    PIECECOLOR m_color;
 
    // external state
    POINT m_point;
};
 
class CGomoku : public CPiece
{
public:
    CGomoku(PIECECOLOR color) : CPiece(color){}
};
 
class CPieceFactory
{
public:
    CPiece *GetPiece(PIECECOLOR color)
    {
        CPiece *pPiece = NULL;
        if (m_vecPiece.empty())
        {
            pPiece = new CGomoku(color);
            m_vecPiece.push_back(pPiece);
        }
        else
        {
            bool bFound = false; // 非常感谢fireace指出的问题
            for (vector<CPiece *>::iterator it = m_vecPiece.begin(); it != m_vecPiece.end(); ++it)
            {
                if ((*it)->GetColor() == color)
                {
                    bFound = true;
                    pPiece = *it;
                    break;
                }
                bFound = false;
            }
            if (!bFound)
            {
                pPiece = new CGomoku(color);
                m_vecPiece.push_back(pPiece);
            }
        }
        return pPiece;
    }
 
    ~CPieceFactory()
    {
        for (vector<CPiece *>::iterator it = m_vecPiece.begin(); it != m_vecPiece.end(); ++it)
        {
            if (*it != NULL)
            {
                delete *it;
                *it = NULL;
            }
        }
    }
 
private:
    vector<CPiece *> m_vecPiece;
};
 
class CChessboard
{
public:
    void Draw(CPiece *piece)
    {
        if (piece->GetColor())
        {
            cout<<"Draw a White"<<" at ("<<piece->GetPoint().x<<","<<piece->GetPoint().y<<")"<<endl;
        }
        else
        {
            cout<<"Draw a Black"<<" at ("<<piece->GetPoint().x<<","<<piece->GetPoint().y<<")"<<endl;
        }
        m_mapPieces.insert(pair<POINT, CPiece *>(piece->GetPoint(), piece));
    }
 
    void ShowAllPieces()
    {
        for (map<POINT, CPiece *>::iterator it = m_mapPieces.begin(); it != m_mapPieces.end(); ++it)
        {
            if (it->second->GetColor())
            {
                cout<<"("<<it->first.x<<","<<it->first.y<<") has a White chese."<<endl;
            }
            else
            {
                cout<<"("<<it->first.x<<","<<it->first.y<<") has a Black chese."<<endl;
            }
        }
    }
 
private:
    map<POINT, CPiece *> m_mapPieces;
};
 
int main()
{
    CPieceFactory *pPieceFactory = new CPieceFactory();
    CChessboard *pCheseboard = new CChessboard();
 
    // The player1 get a white piece from the pieces bowl
    CPiece *pPiece = pPieceFactory->GetPiece(WHITE);
    pPiece->SetPoint(POINT(2, 3));
    pCheseboard->Draw(pPiece);
 
    // The player2 get a black piece from the pieces bowl
    pPiece = pPieceFactory->GetPiece(BLACK);
    pPiece->SetPoint(POINT(4, 5));
    pCheseboard->Draw(pPiece);
 
    // The player1 get a white piece from the pieces bowl
    pPiece = pPieceFactory->GetPiece(WHITE);
    pPiece->SetPoint(POINT(2, 4));
    pCheseboard->Draw(pPiece);
 
    // The player2 get a black piece from the pieces bowl
    pPiece = pPieceFactory->GetPiece(BLACK);
    pPiece->SetPoint(POINT(3, 5));
    pCheseboard->Draw(pPiece);
 
    /*......*/
 
    //Show all cheses
    cout<<"Show all cheses"<<endl;
    pCheseboard->ShowAllPieces();
 
    if (pCheseboard != NULL)
    {
        delete pCheseboard;
        pCheseboard = NULL;
    }
    if (pPieceFactory != NULL)
    {
        delete pPieceFactory;
        pPieceFactory = NULL;
    }
}