C++实现装饰者模式

时间：2016-04-19 14:20:09 阅读：185 评论：0 收藏：0 [点我收藏+]

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多个主题对象，每个主题对象都有三个观察者，感觉有点问题，说不好。有问题请提出来。

[cpp] view plain copy

print ?

/*
观察者模式：定义一种一对多的依赖，让多个观察者同时观察一个对象，当对象状态发生变化时，
会通知所有它的观察者
*/
#include <iostream>
#include <list>
#include <string>
using namespace std;
class Subject;
class Observer
{
protected:
string name;
Subject *subject;
public:
Observer(Subject *subject, string name)
{
this->subject = subject;
this->name = name;
}
virtual void Update()
{}
};
class Subject
{
list<Observer*> observers;
public:
void AddObserver(Observer *observer)
{
observers.push_back(observer);
}
void RemoveObserver(Observer *observer)
{
observers.remove(observer);
}
virtual void Notify()
{
list<Observer*>::iterator iter = observers.begin();
for(; iter != observers.end(); iter++)
{
(*iter)->Update();
}
}
virtual string GetState()
{
return " ";
}
int GetObserverSize()
{
return observers.size();
}
};
class ConcreteSubjectOne:public Subject
{
string state;
public:
ConcreteSubjectOne(string state)
{
this->state ="One " + state;
}
string GetState()
{
return this->state;
}
};
class ConcreteSubjectTwo:public Subject
{
string state;
public:
ConcreteSubjectTwo(string state)
{
this->state ="Two " + state;
}
string GetState()
{
return this->state;
}
};
class ConcreteObserverOne:public Observer
{
public:
ConcreteObserverOne(Subject *subject, string name)
:Observer(subject, name)
{
}
void Update()
{
cout<<"Observer Type One: "<< name << " subject state is "<< subject->GetState()<<endl;
}
};
class ConcreteObserverTwo:public Observer
{
public:
ConcreteObserverTwo(Subject *subject, string name)
:Observer(subject, name)
{
}
void Update()
{
cout<<"Observer Type Two: "<< name << " subject state is "<< subject->GetState()<<endl;
}
};
int main()
{
ConcreteSubjectOne *subject_1 = new ConcreteSubjectOne("subject__1");
ConcreteSubjectTwo *subject_2 = new ConcreteSubjectTwo("subject__2");
ConcreteObserverOne *observer1 = new ConcreteObserverOne(subject_1, "observer 1");
ConcreteObserverOne *observer2 = new ConcreteObserverOne(subject_1, "observer 2");
ConcreteObserverOne *observer3 = new ConcreteObserverOne(subject_1, "observer 3");
ConcreteObserverTwo *observer4 = new ConcreteObserverTwo(subject_2, "observer 4");
ConcreteObserverTwo *observer5 = new ConcreteObserverTwo(subject_2, "observer 5");
ConcreteObserverTwo *observer6 = new ConcreteObserverTwo(subject_2, "observer 6");
subject_1->AddObserver(observer1);
subject_1->AddObserver(observer2);
subject_1->AddObserver(observer3);
subject_2->AddObserver(observer4);
subject_2->AddObserver(observer5);
subject_2->AddObserver(observer6);
subject_1->Notify();
subject_2->Notify();
cout<<subject_1->GetObserverSize()<<endl;
cout<<subject_2->GetObserverSize()<<endl;
delete subject_1;
delete subject_2;
delete observer6;
delete observer5;
delete observer4;
delete observer3;
delete observer2;
delete observer1;
getchar();
return 0;
}

C++实现装饰者模式

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原文地址：http://www.cnblogs.com/h2052519/p/5407817.html

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