C++事件聚合器

事件聚合器（Event Aggregator）允许不同的组件订阅和发布事件，而不需要知道事件的发布者和订阅者是谁，实现模块在不直接相互引用的情况下通信，实现模块间的松耦合。事件聚合器常用语C#语言中，以下为C++语言的简单实现。

C++事件聚合器的实现

#pragma once
#include <map>
#include <functional>
#include <vector>
#include <iostream>

class EventArgBase
{
};

class EventBase
{
};

template<typename TEventArg>
class PubSubEvent : public EventBase
{
public:
	void Sub(std::function<void(TEventArg*)> action)
	{
		actions.push_back(action);
	}

	void Pub(TEventArg* arg)
	{
		for (auto action : actions)
		{
			action(arg);
		}
	}

private:
	std::vector<std::function<void(TEventArg*)>> actions;
};

class EventAggregator
{
public:
	template<typename T>
	static T* GetEvent()
	{
		auto name = typeid(T).raw_name();
		auto itor = events.find(name);

		if (itor != events.end())
		{
			return static_cast<T*>(itor->second);
		}
		else
		{
			events[name] = new T();
			return static_cast<T*>(events[name]);
		}
	}

private:
	static std::map<const char*, EventBase*> events;
};

std::map<const char*, EventBase*> EventAggregator::events;

Demo

#include <iostream>
#include "EventAggregator.h"

class TestEventArg : public EventArgBase
{
public:
	TestEventArg(std::string name)
	{
		this->name = name;
	}

public:
	std::string name;
};

class TestEvent : public PubSubEvent<TestEventArg>
{

};

class TestClass
{
public:
	void DoEvent(TestEventArg* arg)
	{
		std::cout << "TestClass : " << arg->name << std::endl;
	}
};

void test(TestEventArg* arg)
{
	std::cout << arg->name << std::endl;
}

int main()
{
	TestClass testClass;
	
	EventAggregator::GetEvent<TestEvent>()->Sub(test);
	EventAggregator::GetEvent<TestEvent>()->Sub(std::bind(&TestClass::DoEvent, &testClass, std::placeholders::_1));

	EventAggregator::GetEvent<TestEvent>()->Pub(new TestEventArg("hello"));
	EventAggregator::GetEvent<TestEvent>()->Pub(new TestEventArg("world"));
}