大话设计模式观察者模式c++实现

观察者模式

其他二十三种设计模式

#include<iostream>
#include<list>

using namespace std;
//观察者模式
//抽象观察者类
class AbstractObserver {
public:
	virtual void Update(string) = 0;
};

//抽象通知者类
class AbstractSubject {
public:
	//增加观察者
	virtual void Attach(AbstractObserver* _observer) = 0;
	//移除观察者
	virtual void Detach(AbstractObserver* _observer) = 0;
	//通知观察者
	virtual void Notify() = 0;

};

//具体通知者类
class ConcreteSubject :public AbstractSubject {
public:
	//通知者状态
	string SubjectState(string _subjectState) {
		this->subjectState = _subjectState;
		return subjectState;
	}
	//增加观察者
	virtual void Attach(AbstractObserver* _observer) {
		observers.push_back(_observer);
	}
	//移除观察者
	virtual void Detach(AbstractObserver* _observer) {
		observers.remove(_observer);
	}
	//通知观察者
	virtual void Notify() {
		for (list<AbstractObserver*>::iterator i = observers.begin(); i != observers.end(); i++) {
			(*i)->Update(subjectState);
		}
	}

private:
	list<AbstractObserver*> observers;
	string subjectState;
};

//具体观察者类
class ConcreteObserver :public AbstractObserver {
public:
	ConcreteObserver(ConcreteSubject* _subject, string _name) {
		this->subject = _subject;
		this->name = _name;
	}
	virtual void Update(string _subjectState) {
		this->observerState = subject->SubjectState(_subjectState);
		cout << "观察者：" << name << " 状态：" << observerState << endl;
	}
	ConcreteSubject* Subject() {
		return subject;
	}

private:
	string name;
	string observerState;
	ConcreteSubject* subject;
};

void test1() {
	//创建一个通知者
	ConcreteSubject* s = new ConcreteSubject();

	s->Attach(new ConcreteObserver(s, "X"));
	s->Attach(new ConcreteObserver(s, "Y"));
	s->Attach(new ConcreteObserver(s, "Z"));

	s->SubjectState("ABC");
	s->Notify();

	delete s;
}
int main() {
	test1();
	return 0;
}