设计模式：command模式

目的：将命令设计成类的形式，并可以组织成队列

优点：

• 在需要的情况下，可以比较容易地将命令记入日志
• 可以容易的实现对请求的撤销和重做
• 由于新的具体命令类不影响其他的命令类，因此增加新的具体命令类很容易

例子：

class Receiver
{
public:
	void action()
	{
		cout << "do action." << endl;
	}
};

class Icommand
{
public:
	virtual void excute() = 0;
};

class CommondFirst: public Icommand
{
	Receiver* receive;
public:
	CommondFirst(Receiver* receive)
	{
		this->receive = receive;
	}

	void excute()
	{
		cout << "CommondFirst: " << endl;
		receive->action();
	}
};

class CommondSecond: public Icommand
{
	Receiver* receive;
public:
	CommondSecond(Receiver* receive)
	{
		this->receive = receive;
	}

	void excute()
	{
		cout << "CommondSecond: " << endl;
		receive->action();
	}
};

class Invoker
{
	vector<Icommand*> v;
public:
	
	void addCommand(Icommand* c)
	{
		v.push_back(c);
	}
	
	void clear()
	{
		v.clear();
	}
	
	void Notify()
	{
		for(vector<Icommand*>::iterator it=v.begin(); it!=v.end(); ++it)
		{
			(*it)->excute();
		}
	}
};

int main() 
{
	Receiver* r = new Receiver();
	CommondFirst* cf = new CommondFirst(r);
	CommondSecond* cs = new CommondSecond(r);
	
	Invoker* invoker = new Invoker();
	invoker->addCommand(cf);
	invoker->addCommand(cs);
	invoker->Notify();
	
	return 0;
}