设计模式学习_命令模式

Posted 2021-08-05 Leslie X徐

命令模式

概述

将"请求"封装成对象,以便使用不同的请求,队列或日志来参数化其他对象.命令模式也支持可撤销的操作.

项目

实现智能化遥控器控制不同的设备
采用命令模式, 从逻辑上将遥控器的类和各设备的类解偶.

命令接口

//----------------命令接口------------------
class Command{
	public:
	virtual ~Command(){} //虚析构
	virtual void execute()=0;
};

无效指令

class NoCommand:
	public Command
{
	public:
	NoCommand() :Command() {}
	void execute(){}
};

实现遥控器

//---------------实现遥控器----------------
class RemoteControl{
	Command* onCommands[7];
	Command* offCommands[7];
	
	public:
	RemoteControl(){
		Command *noCommand = new NoCommand();
		for(int i=0; i<7; ++i){
			onCommands[i] = noCommand;
			offCommands[i] = noCommand;
		}
		//不加上noCommand指针指向未知会段错误
	}
		
	void setCommand(int slot, Command *onCommand, Command *offCommand){
		onCommands[slot] = onCommand;
		offCommands[slot] = offCommand;
	} 
		
	void onButtonPushed(int slot){
		onCommands[slot]->execute();
	}
	
	void offButtonPushed(int slot){
		offCommands[slot]->execute();
	}
		
};

实现命令

灯设备和命令

//灯设备
class Light{
	string light;
	public:
	Light(){}
	Light(string light){this->light = light;}
	void on(){cout<<light<<" is on\\n";}
	void off(){cout<<light<<" is off\\n";}
};

//开关灯
class LightOnCommand:
	public Command
{
	Light light;
	
	public:
	LightOnCommand(Light &light){
		this->light = light;
	}
	
	void execute(){
		this->light.on();
	}
};

class LightOffCommand:
public Command
{
	Light light;
	
	public:
	LightOffCommand(Light &light){
		this->light = light;
	}
	
	void execute(){
		this->light.off();
	}
};

音响设备和命令

//音响设备
class Stereo{
	string stereo;
	public:
	Stereo(){}
	Stereo(string stereo){this->stereo = stereo;}
	void on(){cout<<stereo<<" is on\\n";}
	void setCd(){cout<<"insert CD\\n";}
	void setVolume(int vol){cout<<"set vol: "<<vol<<endl;}
	
	void off(){cout<<"Stereo is off\\n";}
};

//开关音响
class StereoOnWithCDCommand:
public Command
{
	Stereo stereo;
	
	public:
	StereoOnWithCDCommand(Stereo &stereo){
		this->stereo = stereo;
	}
	
	void execute(){
		this->stereo.on();
		this->stereo.setCd();
		this->stereo.setVolume(11);
	}
};

class StereoOffCommand:
public Command
{
	Stereo stereo;
	
	public:
	StereoOffCommand(Stereo &stereo){
		this->stereo = stereo;
	}
	
	void execute(){
		this->stereo.off();
	}
};

主函数测试

int main(int argc, char **argv)
{
//实例化遥控器
	RemoteControl remotectl;
	
//实例化各个设备及其开关命令
	Light livingRoomLight("livingRoomLight");
	LightOnCommand livingRoomLightOn(livingRoomLight);
	LightOffCommand livingRoomLightOff(livingRoomLight);
	
	Light dinningRoomLight("dinningRoomLight");
	LightOnCommand dinningRoomLightOn(dinningRoomLight);
	LightOffCommand dinningRoomLightOff(dinningRoomLight);
	
	Stereo livingRoomStereo("livingRoomStereo");
	StereoOnWithCDCommand stereoOn(livingRoomStereo);
	StereoOffCommand stereoOff(livingRoomStereo);
	
//设置遥控器各槽对应指令
	remotectl.setCommand(0,&livingRoomLightOn,&livingRoomLightOff);
	remotectl.setCommand(1,&dinningRoomLightOn,&dinningRoomLightOff);
	remotectl.setCommand(2,&stereoOn,&stereoOff);
	

	char OnOrOff;
	int slot;
	while(1){
		cout<<"请输入命令: ";
		cin>>OnOrOff>>slot;
		if(OnOrOff=='n') remotectl.onButtonPushed(slot);
		if(OnOrOff=='f') remotectl.offButtonPushed(slot);
		if(OnOrOff=='q') break;
	}
	return 0;
}

输出

请输入命令: n0
livingRoomLight is on
请输入命令: n1
dinningRoomLight is on
请输入命令: n2
livingRoomStereo is on
insert CD
set vol: 11
请输入命令: n3
请输入命令: f0
livingRoomLight is off
请输入命令: f1
dinningRoomLight is off
请输入命令: f2
Stereo is off
请输入命令: q