享元模式

软件设计                  石家庄铁道大学信息学院

 

实验13：享元模式

本次实验属于模仿型实验，通过本次实验学生将掌握以下内容：

1、理解享元模式的动机，掌握该模式的结构；

2、能够利用享元模式解决实际问题。

 

 

[实验任务一]：围棋

设计一个围棋软件，在系统中只存在一个白棋对象和一个黑棋对象，但是它们可以在棋盘的不同位置显示多次。

实验要求：

1.  提交类图；

 

 

 

2.  提交源代码；

#include <iostream>
#include <map>
#include <vector>
using namespace std;

typedef struct Coordinates
{
    int x;
    int y;

    Coordinates(){}
    Coordinates(int a, int b){x=a;y=b;}

    bool operator <(const Coordinates& 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 IgoChessmanFactory
{
public:
    CPiece *GetPiece(PIECECOLOR color)
    {
        CPiece *pPiece = NULL;
    if (m_vecPiece.empty())
    {
        pPiece = new CGomoku(color);
        m_vecPiece.push_back(pPiece);
    }
    else
    {
        for (vector<CPiece *>::iterator it = m_vecPiece.begin(); it != m_vecPiece.end(); ++it)
        {
            if ((*it)->GetColor() == color)
        {
            pPiece = *it;
            break;
        }
        }
        if (pPiece == NULL)
        {
        pPiece = new CGomoku(color);
        m_vecPiece.push_back(pPiece);
        }
     }
        return pPiece;
    }

    ~IgoChessmanFactory()
    {
        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 IgoChessman
{
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()
{
    IgoChessmanFactory *pPieceFactory = new IgoChessmanFactory();
    IgoChessman *pCheseboard = new IgoChessman();

    // 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);
}

 

 

 

 

 

 

 

 

 

 

3.注意编程规范；

4.要求用简单工厂模式和单例模式实现享元工厂类的设计。