设计模式读书笔记：Decorator（装饰）

来源：互联网发布：淘宝查号编辑：程序博客网时间：2024/06/07 22:55

意图：

动态地给一个对象添加一些额外的职责。就增加功能来说，Decorator模式相比生成子类更为灵活。

结构图：来自《23种设计模式 - 郗晓勇》

实现：https://github.com/panshiqu/patterns/tree/master/Decorator

Component

namespace NS_DECORATOR {class Component {public:Component() {}virtual ~Component() {}virtual void operation(void) = 0;};} /* namespace NS_DECORATOR */

ConcreteComponent

#include "Component.h"#include <iostream>namespace NS_DECORATOR {class ConcreteComponent : public Component{public:ConcreteComponent() {}virtual ~ConcreteComponent() {}virtual void operation(void){std::cout << "ConcreteComponent" << std::endl;}};} /* namespace NS_DECORATOR */

Decorator

#include "Component.h"namespace NS_DECORATOR {class Decorator : public Component{public:Decorator(Component *component) : _component(component) {}virtual ~Decorator() {}virtual void operation(void){_component->operation();}private:Component *_component;};} /* namespace NS_DECORATOR */

ConcreteDecoratorA

#include "Decorator.h"#include <iostream>namespace NS_DECORATOR {class ConcreteDecoratorA : public Decorator{public:ConcreteDecoratorA(Component *component) : Decorator(component) {}virtual ~ConcreteDecoratorA() {}virtual void operation(void){Decorator::operation();addBehavior();}void addBehavior(void){std::cout << "Jump" << std::endl;}};} /* namespace NS_DECORATOR */

ConcreteDecoratorB

#include "Decorator.h"#include <iostream>namespace NS_DECORATOR {class ConcreteDecoratorB : public Decorator{public:ConcreteDecoratorB(Component *component) : Decorator(component) {}virtual ~ConcreteDecoratorB() {}virtual void operation(void){Decorator::operation();addBehavior();}void addBehavior(void){std::cout << "Move" << std::endl;}};} /* namespace NS_DECORATOR */

main

#include "Decorator/ConcreteComponent.h"#include "Decorator/ConcreteDecoratorA.h"#include "Decorator/ConcreteDecoratorB.h"using namespace NS_DECORATOR;using namespace std;int main(void){ConcreteComponent cc;cc.operation();cout << "----------" << endl;ConcreteDecoratorA cda(&cc);cda.operation();cout << "----------" << endl;ConcreteDecoratorB cdb(&cda);cdb.operation();}

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