用代码和UML图化解设计模式之《装饰模式》

这个模式看了两次，因为我有点不太理解，其实到现在也不太理解。

通过写代码，自我理解就是把对象重新装饰了一遍。通过继承同一个基类。而不用添加额外的类了。。。。

上图吧

通过修饰类达到我们想要的效果。修饰类通常初始化了基类。

[cpp]
// Decorator.cpp : 定义控制台应用程序的入口点。
//************************************************************************/
/* @filename    Decorator.cpp
@author       wallwind
@createtime    2012/10/29 22:42
@function     命令模式
@email      */
/************************************************************************/

#include "stdafx.h"
#include <iostream>

using namespace std;

class Widget
{
public:
    Widget(){}
    virtual ~Widget(){}

    virtual void show()=0;
};

class TextField:public Widget
{
public:
    TextField(int ix,int iy)
        :x(ix),y(iy)
    {

    }
    ~TextField(){}

    void show()
    {
        cout<<"x:"<<x<<endl;
        cout<<"y:"<<y<<endl;

    }
private:
    int x;
    int y;
};
class Decorator:public Widget
{
public:
    Decorator(Widget* widget)
        :m_widget(widget)
    {}
    virtual ~Decorator()
    {
        delete m_widget;
    }

    void show()
    {
        m_widget->show();
        cout<<"Decorator:show()"<<endl;
    }
private:
    Widget* m_widget;
};

class BorderDecorator :public Decorator
{
public:
    BorderDecorator(Widget* widget)
        :Decorator(widget)
    {

    }
    void show()
    {
        Decorator::show();
        cout<<"BorderDecorator:show()"<<endl;
    }
};

class ScrollDecorator :public Decorator
{
public:
    ScrollDecorator(Widget* widget)
        :Decorator(widget)
    {

    }

    void show()
    {
        Decorator::show();
        cout<<"ScrollDecorator:show()"<<endl;
    }
};

int _tmain(int argc, _TCHAR* argv[])
{

    Widget* twidget = new TextField(2,3);
    Widget *sd = new ScrollDecorator(twidget);
    Widget *br = new BorderDecorator(twidget);

    sd->show();
    br->show();
    return 0;
}

补充：软件开发 , C++ ,