装饰者模式（Decorator Pattern）

装饰者模式（Decorator Pattern）：动态地给一个对象添加一些额外的职责，就增加功能来说，装饰者模式比生成子类更加灵活。

 

#ifndef DECORATOR_H
#define DECORATOR_H

#include<iostream>
using namespace std;

class Component
{
public:
    virtual void operation()=0;
};

class ConcreteComponent:public Component
{
public:
    void operation()
    {
        cout<<"ConcreteComponent:operation()"<<endl;
    }
};

class Decorator:public Component
{
protected:
    Component* wappedObj;
public:
    Decorator(Component* component){
        wappedObj=component;
    }
};

class ConcreteDecoratorA:public Decorator
{
public:
    ConcreteDecoratorA(Component* component):Decorator(component){}

    void operation()
    {
        wappedObj->operation();
        cout<<"ConcreteDecoratorA:operation()"<<endl;
    }
};

class ConcreteDecoratorB:public Decorator
{
public:
    ConcreteDecoratorB(Component* component):Decorator(component){}

    void operation()
    {
        wappedObj->operation();
        cout<<"ConcreteDecoratorB:operation()"<<endl;
    }
};

#endif//DECORATOR_H

int main()
{

    Component* component=new ConcreteComponent();
    component->operation();
    cout<<endl;

    component=new ConcreteDecoratorB(component);
    component->operation();
    cout<<endl;

    component=new ConcreteDecoratorA(component);
    component->operation();
    cout<<endl;

     return 0;
}