35 lines
762 B
C++
35 lines
762 B
C++
/**
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* @name 观察者模式
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* @brief: 定义对象间一对多的依赖关系
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* @note 场景：事件处理系统、消息订阅、MVC 模型更新视图
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*/
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#include <string>
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#include <vector>
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class Observer {
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public:
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virtual void update(const std::string& msg) = 0;
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};
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class Subject {
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std::vector<Observer*> observers;
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public:
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void attach(Observer* o) { observers.push_back(o); }
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void notify(const std::string& msg) {
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for (auto o : observers) o->update(msg);
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}
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};
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class ConcreteObserver : public Observer {
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void update(const std::string& msg) override { /* 处理消息 */ }
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};
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// 使用
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int main()
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{
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Subject subject;
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subject.attach(new ConcreteObserver());
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subject.notify("Event occurred!");
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return 0;
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} |