C++设计模式——装饰模式

最新推荐文章于 2024-11-02 18:40:34 发布

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本文通过一个具体的C++实现示例，详细介绍了软件设计中的装饰者模式。该模式允许在不改变原有组件的情况下增加新的功能，通过使用继承自同一接口的不同装饰类来扩展核心功能。

#include <iostream>
using namespace std;


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

class ConcreteComponent : public Component
{
public:
    virtual void Operation()
    {
        cout << "I am no decoratored ConcreteComponent" << endl;
    }
};

class Decorator :public Component
{
private:
    Component *m_pComponent;
public:
    Decorator(Component *p)
    {
        m_pComponent = p;
    }

    void Operation()
    {
        m_pComponent->Operation();
    }
};

class ConcreteDecoratorA : public Decorator
{
public:
    ConcreteDecoratorA(Component *p) :Decorator(p)
    {
    }
    void  AddedBehavior()
    {
        cout << "This is added behavior A." << endl;
    }

    void Operation()
    {
        AddedBehavior();
        Decorator::Operation();
    }

};

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

    void  AddedBehavior()
    {
        cout << "This is added behavior B." << endl;
    }

    void Operation()
    {
        AddedBehavior();
        Decorator::Operation();
    }

};

int main()
{
    Component *pComponent = new ConcreteComponent();
    Decorator *pDecA = new ConcreteDecoratorA(pComponent);
    pDecA->Operation();


    Decorator *pDecB = new ConcreteDecoratorB(pComponent);
    pDecB->Operation();

    Decorator *pDecAB = new ConcreteDecoratorB(pDecA);
    pDecAB->Operation();

    delete pDecAB;
    pDecAB = NULL;

    delete pDecB;
    pDecB = NULL;

    delete pDecA;
    pDecA = NULL;

    delete pComponent;
    pComponent = NULL;
    return 0;
}