命令模式-宏命令+状态撤销

青旅半醒 2022-07-12 12:18 107阅读 0赞

package F\_Command.b;

/\*\*  
\* 宏命令以及状态撤销  
\* CeilingFan：可撤销状态  
\*/  
public class Main \{  
public static void main(String\[\] args) \{  
RemoteControl remote = new RemoteControl();  
Light light = new Light();  
Stereo stereo = new Stereo();

/**
         * 创建电灯和音响的所有命令
         */
        LightOnCommand lightOnCommand = new LightOnCommand(light);
        LightOffCommand lightOffCommand = new LightOffCommand(light);
        StereoOnWithCDCommand stereoOnWithCDCommand = new StereoOnWithCDCommand(
                stereo);
        StereoOffWithCDCommand stereoOffWithCDCommand = new StereoOffWithCDCommand(
                stereo);
    
        // 命令加载到遥控器插槽中
        remote.setCommand(0, lightOnCommand, lightOffCommand);
        remote.setCommand(1, stereoOnWithCDCommand, stereoOffWithCDCommand);
    
        System.out.println(remote);
    
        remote.onButtonWasPushed(0);
        remote.offButtonWasPushed(0);
        remote.undoButtonWasPushed();
        remote.onButtonWasPushed(1);
        remote.offButtonWasPushed(1);
    
        System.out.println("===========");
        // 使用宏命令
        Command[] partyOn = { lightOnCommand, stereoOnWithCDCommand };
        Command[] partyOff = { lightOffCommand, stereoOffWithCDCommand };
        MacroCommand partOnMacro = new MacroCommand(partyOn);
        MacroCommand partyOffMacro = new MacroCommand(partyOff);
        remote.setCommand(2, partOnMacro, partyOffMacro);
        remote.onButtonWasPushed(2);
        remote.offButtonWasPushed(2);
        remote.undoButtonWasPushed();
    
    }

\}  
package F\_Command.b;

public class NoCommand implements Command \{

@Override
    public void execute() {
    }
    
    @Override
    public void undo() {
    
    }

\}  
package F\_Command.b;

import java.util.Arrays;

public class RemoteControl \{  
Command\[\] onCommands;  
Command\[\] offCommands;  
// 记录执行命令的前一个对象，方便撤销动作  
Command undoCommand;

/**
     * 初始化遥控器7个开与关的命令
     */
    public RemoteControl() {
        onCommands = new Command[7];
        offCommands = new Command[7];
        NoCommand noCommand = new NoCommand();
        for (int i = 0; i < 7; i++) {
            onCommands[i] = noCommand;
            offCommands[i] = noCommand;
        }
        // 一开始没有前一个动作，初始化
        undoCommand = noCommand;
    }
    
    public void setCommand(int slot, Command onCommand, Command offCommand) {
        onCommands[slot] = onCommand;
        offCommands[slot] = offCommand;
    }
    
    public void onButtonWasPushed(int slot) {
        onCommands[slot].execute();
        undoCommand = onCommands[slot];
    }
    
    public void offButtonWasPushed(int slot) {
        offCommands[slot].execute();
        undoCommand = offCommands[slot];
    }
    
    // 执行撤销方法
    public void undoButtonWasPushed() {
        undoCommand.undo();
    }
    
    @Override
    public String toString() {
        return "RemoteControl [onCommands=" + Arrays.toString(onCommands)
                + ", offCommands=" + Arrays.toString(offCommands) + "]";
    }

\}  
package F\_Command.b;

public class Stereo \{  
public void on() \{  
System.out.println(“on”);  
\}

public void setCD() {
        System.out.println("setCD");
    }
    
    public void off() {
        System.out.println("off");
    }

\}  
package F\_Command.b;

/\*\*  
\* 实现打开电灯的命令  
\*  
\*/  
public class StereoOffWithCDCommand implements Command \{

Stereo stereo;
    
    public StereoOffWithCDCommand(Stereo stereo) {
        this.stereo = stereo;
    }
    
    public void execute() {
        stereo.off();
    }
    
    @Override
    public void undo() {
        stereo.on();
    }

\}  
package F\_Command.b;

/\*\*  
\* 实现打开电灯的命令  
\*  
\*/  
public class StereoOnWithCDCommand implements Command \{

Stereo stereo;
    
    public StereoOnWithCDCommand(Stereo stereo) {
        this.stereo = stereo;
    }
    
    public void execute() {
        stereo.on();
        stereo.setCD();
    }
    
    @Override
    public void undo() {
        stereo.off();
    }

\}  
package F\_Command.b;

/\*\*  
\* 使用宏命令执行一堆任务  
\*/  
public class MacroCommand implements Command \{  
Command\[\] commands;

public MacroCommand(Command[] commands) {
        this.commands = commands;
    }
    
    @Override
    public void execute() {
        for (int i = commands.length - 1; i >= 0; i--) {
            commands[i].execute();
        }
    }
    
    @Override
    public void undo() {
        for (int i = commands.length - 1; i >= 0; i--) {
            commands[i].undo();
        }
    }

\}  
package F\_Command.b;

/\*\*  
\* 实现打开电灯的命令  
\*  
\*/  
public class LightOnCommand implements Command \{  
Light light;

public LightOnCommand(Light light) {
        this.light = light;
    }
    
    public void execute() {
        light.on();
    }
    
    @Override
    public void undo() {
        light.off();
    }

\}  
package F\_Command.b;

/\*\*  
\* 实现打开电灯的命令  
\*  
\*/  
public class LightOffCommand implements Command \{  
Light light;

public LightOffCommand(Light light) {
        this.light = light;
    }
    
    public void execute() {
        light.off();
    }
    
    @Override
    public void undo() {
        light.on();
    }

\}  
package F\_Command.b;

public class Light \{  
public void on() \{  
System.out.println(“on”);  
\}

public void off() {
        System.out.println("off");
    }

\}  
package F\_Command.b;

/\*\*  
\* 命令接口  
\*  
\*/  
public interface Command \{  
void execute();

void undo();

\}  
package F\_Command.b;

public class CeilingFanHighCommand implements Command \{  
CeilingFan ceilingFan;  
// 方便追踪之前的状态  
int prevSpeed;

public CeilingFanHighCommand(CeilingFan ceilingFan) {
        this.ceilingFan = ceilingFan;
    }
    
    public void execute() {
        prevSpeed = ceilingFan.getSpeed();
        ceilingFan.high();
    }
    
    public void undo() {
        if (prevSpeed == CeilingFan.HIGH)
            ceilingFan.high();
        else if (prevSpeed == CeilingFan.MEDIUM)
            ceilingFan.medium();
        else if (prevSpeed == CeilingFan.LOW)
            ceilingFan.low();
        else if (prevSpeed == CeilingFan.OFF)
            ceilingFan.off();
    }

\}  
package F\_Command.b;

/\*\*  
\* 吊扇类  
\* 使用状态进行撤销  
\*/  
public class CeilingFan \{

public static final int HIGH = 3;
    public static final int MEDIUM = 2;
    public static final int LOW = 1;
    public static final int OFF = 0;
    
    String location;
    int speed;
    
    public CeilingFan(String location) {
        this.location = location;
        speed = OFF;
    }
    
    public void high() {
        speed = HIGH;
    }
    
    public void medium() {
        speed = MEDIUM;
    }
    
    public void low() {
        speed = LOW;
    }
    
    public void off() {
        speed = OFF;
    }
    
    public int getSpeed() {
        return speed;
    }