设计模式——装饰器模式（C++实现）

#include <iostream>
#include <string>

using namespace std;

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

class ConcreteComponentA: public Component
{
public:
        virtual void operation()
        {
                cout<< "ConcreteComponentA....."<< endl;
        }
};

class ConcreteComponentB: public Component
{
public:
        virtual void operation()
        {
                cout<< "ConcreteComponentB....."<< endl;
        }
};

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

        virtual void operation() = 0;

        Component* component;
};

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

        void operation()
        {
                component->operation();
                AddBehavior();
        }

        void AddBehavior()
        {
                cout<< "ConcreteDecoratorA....."<< endl;
        }
};

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

        void operation()
        {
                component->operation();
                AddBehavior();
        }

        void AddBehavior()
        {
                cout<< "ConcreteDecoratorB....."<< endl;
        }
};

int main(int argc, char* argv[])
{
        ConcreteComponentB* ccB = new ConcreteComponentB();

        ConcreteDecoratorA* cdA1 = new ConcreteDecoratorA(ccB);

        ConcreteDecoratorA* cdA2 = new ConcreteDecoratorA(cdA1);

        ConcreteDecoratorB* cdB1 = new ConcreteDecoratorB(cdA1);

        cdA1->operation();cout<< endl;
        cdA2->operation();cout<< endl;
        cdB1->operation();cout<< endl;

        return 0;
}

///////////////////////////
[root]$ ./decorator                   
ConcreteComponentB.....
ConcreteDecoratorA.....

ConcreteComponentB.....
ConcreteDecoratorA.....
ConcreteDecoratorA.....

ConcreteComponentB.....
ConcreteDecoratorA.....
ConcreteDecoratorB.....