设计模式之命令模式（Command）

#pragma once
#include <string>
#include <list>
#include <map>

//暴露接口层
class Command
{
public:
virtual ~Command(void);
virtual bool execute() = 0;

protected:
Command();
};

//简单命令类，便于不同对象的创建
template<class Receiver>
class SimpleCommand : public Command
{
public:
typedef bool (Receiver::* Action)();
SimpleCommand(Receiver* _t, Action _action): t_(_t), action_(_action) { }
virtual bool execute() { return (t_->*action_)(); } //模板函数要暴露在声明处

private:
Action action_;
Receiver* t_;
};

//特殊命令类，用于管理一组命令
class MacroCommand : public Command
{
public:
MacroCommand();
virtual ~MacroCommand();

virtual void add(const std::string& id, Command* cmd);
virtual void remove(const std::string& id);

virtual bool execute();

private:
typedef std::map<std::string, Command*> CmdList;
CmdList cmdlist_;
};

//自定义的一个可以执行命令的类
class MyCmd
{
public:
bool Action();
};