Flyweight pattern

Flyweight pattern

1.소스

#include <stdio.h>
#include <iostream>
#include <string>
#include <cstring>

using namespace std;

class Icon
{

public:
    Icon(char *fileName)
    {
        strcpy(_name, fileName);
        if (!strcmp(fileName, "go"))
        {
            _width = 20;
            _height = 20;
        }
        if (!strcmp(fileName, "stop"))
        {
            _width = 40;
            _height = 40;
        }
        if (!strcmp(fileName, "select"))
        {
            _width = 60;
            _height = 60;
        }
        if (!strcmp(fileName, "undo"))
        {
            _width = 30;
            _height = 30;
        }
    }

    const char *getName()
    {
        return _name;
    }

    void draw(int x, int y)
    {
        cout << "   drawing " << _name << ": upper left (" << x << "," << y <<   ") - lower right (" << x + _width << "," << y + _height << ")" << endl;
    }

private:
    char _name[20];
    int _width;
    int _height;
};


class FlyweightFactory
{
public:
    static Icon *getIcon(char *name)
    {
        for (int i = 0; i < _numIcons; i++)
		{
          if (!strcmp(name, _icons[i]->getName()))
            return _icons[i];
		}
			
        _icons[_numIcons] = new Icon(name);
        return _icons[_numIcons++];
    }
	
    static void reportTheIcons()
    {
        cout << "Active Flyweights: ";
        for (int i = 0; i < _numIcons; i++)
		{
          cout << _icons[i]->getName() << " ";
		}
        cout << endl;
    }
	
private:
    enum
    {
        MAX_ICONS = 5
    };
	
    static int _numIcons;
    static Icon *_icons[MAX_ICONS];
};

int FlyweightFactory::_numIcons = 0;
Icon *FlyweightFactory::_icons[];

class DialogBox
{
public:
    DialogBox(int x, int y, int incr): 
    _iconsOriginX(x), 
	_iconsOriginY(y),
    _iconsXIncrement(incr){}
	
virtual void draw() = 0;

protected:
    Icon *_icons[3];
    int _iconsOriginX;
    int _iconsOriginY;
    int _iconsXIncrement;
};

class FileSelection: public DialogBox
{
public:
    FileSelection(Icon *first, Icon *second, Icon *third): DialogBox(100, 100, 100)
    {
        _icons[0] = first;
        _icons[1] = second;
        _icons[2] = third;
    }
	
    void draw()
    {
        cout << "drawing FileSelection:" << endl;
        for (int i = 0; i < 3; i++) 
		{
          _icons[i]->draw(_iconsOriginX + (i *_iconsXIncrement), _iconsOriginY);
		}
    }
};

class CommitTransaction: public DialogBox
{
  public:
    CommitTransaction(Icon *first, Icon *second, Icon *third): DialogBox(150, 150, 150 )
    {
        _icons[0] = first;
        _icons[1] = second;
        _icons[2] = third;
    }
	
    void draw()
    {
        cout << "drawing CommitTransaction:" << endl;
        for (int i = 0; i < 3; i++)
		{
          _icons[i]->draw(_iconsOriginX + (i *_iconsXIncrement), _iconsOriginY);
		}
    }
};


int main()
{

    DialogBox *dialogs[2];
	
    dialogs[0] = new FileSelection( FlyweightFactory::getIcon( (char *)("go") ), 
				                    FlyweightFactory::getIcon((char *)("stop")), 
				   				    FlyweightFactory::getIcon( (char *)("select"))
								);

    dialogs[1] = new CommitTransaction( FlyweightFactory::getIcon( (char *)("select")), 
	                                    FlyweightFactory::getIcon((char *)("stop")), 
										FlyweightFactory::getIcon( (char *)("undo"))
									);

    for (int i = 0; i < 2; i++)
        dialogs[i]->draw();

    FlyweightFactory::reportTheIcons();
}

2.결과

g++ -o flyweight flyweight.cpp

hacker@HACKER:~/cpp$
hacker@HACKER:~/cpp$
hacker@HACKER:~/cpp$ ./flyweight
drawing FileSelection:
   drawing go: upper left (100,100) - lower right (120,120)
   drawing stop: upper left (200,100) - lower right (240,140)
   drawing select: upper left (300,100) - lower right (360,160)
drawing CommitTransaction:
   drawing select: upper left (150,150) - lower right (210,210)
   drawing stop: upper left (300,150) - lower right (340,190)
   drawing undo: upper left (450,150) - lower right (480,180)
Active Flyweights: go stop select undo