デザインモード-コマンドモード(command pattern)キャンセル(undo)詳細

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コマンドモード(command pattern)キャンセル(undo)詳細

この記事のアドレス: http://blog.csdn.net/caroline_wendy

参照コマンドモード: http://blog.csdn.net/caroline_wendy/articale/detail/31379977

コマンドモードは、キャンセル操作を実行するために使用できます。

具体的な方法：
1.対象クラスにはlevelのような状態が必要です。

package command;

public class CeilingFan {
	String location = "";
	int level;
	public static final int HIGH = 3;
	public static final int MEDIUM = 2;
	public static final int LOW = 1;
	public static final int OFF = 0;
 
	public CeilingFan(String location) {
		this.location = location;
	}
  
	public void high() {
		// turns the ceiling fan on to high
		level = HIGH;
		System.out.println(location + " ceiling fan is on high");
 
	} 

	public void medium() {
		// turns the ceiling fan on to medium
		level = MEDIUM;
		System.out.println(location + " ceiling fan is on medium");
	}

	public void low() {
		// turns the ceiling fan on to low
		level = LOW;
		System.out.println(location + " ceiling fan is on low");
	}
 
	public void off() {
		// turns the ceiling fan off
		level = OFF;
		System.out.println(location + " ceiling fan is off");
	}
 
	public int getSpeed() {
		return level;
	}
}

2.コマンドインターフェースは、取消し（undo）操作を含み、即ち、着信先の状態パラメータに基づいて、具体的な取消し動作を判断する。

/**
 * @time 2014 6 9 
 */
package command;

/**
 * @author C.L.Wang
 *
 */
public interface Command {
	public void execute();
	public void undo(); //  
}

3.具体的な命令（Concrete Command）類の必要性を実現し、操作を取り消し、異なる状態によって、異なる取消操作を実行する。

/**
 * @time 2014 6 16 
 */
package command;

/**
 * @author C.L.Wang
 *
 */
public class CeilingFanHighCommand implements Command {

	CeilingFan ceilingFan;
	
	int prevSpeed;
	
	public CeilingFanHighCommand(CeilingFan ceilingFan) {
		this.ceilingFan = ceilingFan;
	}
	
	/* (non-Javadoc)
	 * @see command.Command#execute()
	 */
	@Override
	public void execute() {
		// TODO Auto-generated method stub
		prevSpeed = ceilingFan.getSpeed();
		ceilingFan.high();
	}

	/* (non-Javadoc)
	 * @see command.Command#undo()
	 */
	@Override
	public void undo() {
		// TODO Auto-generated method stub
		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 command;

public class CeilingFanMediumCommand implements Command {
	CeilingFan ceilingFan;
	int prevSpeed;
  
	public CeilingFanMediumCommand(CeilingFan ceilingFan) {
		this.ceilingFan = ceilingFan;
	}
 
	public void execute() {
		prevSpeed = ceilingFan.getSpeed();
		ceilingFan.medium();
	}
 
	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 command;

public class CeilingFanLowCommand implements Command {
	CeilingFan ceilingFan;
	int prevSpeed;
  
	public CeilingFanLowCommand(CeilingFan ceilingFan) {
		this.ceilingFan = ceilingFan;
	}
 
	public void execute() {
		prevSpeed = ceilingFan.getSpeed();
		ceilingFan.low();
	}
 
	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 command;

public class CeilingFanOffCommand implements Command {
	CeilingFan ceilingFan;
	int prevSpeed;
  
	public CeilingFanOffCommand(CeilingFan ceilingFan) {
		this.ceilingFan = ceilingFan;
	}
 
	public void execute() {
		prevSpeed = ceilingFan.getSpeed();
		ceilingFan.off();
	}
 
	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();
		}
	}
}

4.受け入れ者（Receiver）類は、キャンセル操作を実現します。すなわち、コマンドを呼び出した時に、保留コマンドを保留し、キャンセル操作を実行した時に、保留コマンドを呼び出します。

/**
 * @time 2014 6 16 
 */
package command;

/**
 * @author C.L.Wang
 *
 */
public class RemoteControl {

	Command[] onCommands; // 
	Command[] offCommands; // 
	Command undoCommand; //  
	
	public RemoteControl() {
		onCommands = new Command[7];
		offCommands = new Command[7];
		
		Command noCommand = new NoCommand();
		
		for (int i=0; i<7; ++i) { //   
			onCommands[i] = noCommand;
			offCommands[i] = noCommand;
		}
		
		undoCommand = noCommand;
	}
	
	public void setCommand (int slot, Command onCommand, Command offCommand) {
		this.onCommands[slot] = onCommand;
		this.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];
	}
	
	public void undoButtonWasPushed() {
		undoCommand.undo();
	}
	
	public String toString() {
		StringBuffer stringBuffer = new StringBuffer();
		stringBuffer.append("
------ Remote Control ------
");
		for (int i=0; i

5.試験クラスは、異なるコマンドを呼び出し、異なる状態を保存し、取消操作を実行します。

/**
 * @time 2014 6 16 
 */
package command;

import javax.crypto.spec.IvParameterSpec;

/**
 * @author C.L.Wang
 *
 */
public class RemoteLoader {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		RemoteControl remoteControl = new RemoteControl();
		
		Light livingRoomLight = new Light("Living Room");
		Light kitchenLight = new Light("Kitchen");
		CeilingFan ceilingFan = new CeilingFan("Living Room");
		GarageDoor garageDoor = new GarageDoor("");
		Stereo stereo = new Stereo("Living Room");
		
		LightOnCommand livingRoomLightOn = new LightOnCommand(livingRoomLight);
		LightOffCommand livingRoomLightOff = new LightOffCommand(livingRoomLight);
		LightOnCommand kitchenLightOn = new LightOnCommand(kitchenLight);
		LightOffCommand kitchenLightOff = new LightOffCommand(kitchenLight);
		
		CeilingFanHighCommand ceilingFanHigh = new CeilingFanHighCommand(ceilingFan);
		CeilingFanMediumCommand ceilingFanMedium = new CeilingFanMediumCommand(ceilingFan);
		CeilingFanOffCommand ceilingFanOff = new CeilingFanOffCommand(ceilingFan);
		
		GarageDoorOnCommand garageDoorOn = new GarageDoorOnCommand(garageDoor);
		GarageDoorOffCommand garageDoorOff = new GarageDoorOffCommand(garageDoor);
		
		StereoOnWithCDCommand stereoOnWithCD = new StereoOnWithCDCommand(stereo);
		StereoOffCommand stereoOffCommand = new StereoOffCommand(stereo);
		
		remoteControl.setCommand(0, livingRoomLightOn, livingRoomLightOff); //     
		remoteControl.setCommand(1, kitchenLightOn, kitchenLightOff);
		remoteControl.setCommand(2, ceilingFanHigh, ceilingFanOff);
		remoteControl.setCommand(3, ceilingFanMedium, ceilingFanOff);
		remoteControl.setCommand(4, stereoOnWithCD, stereoOffCommand);
		
		remoteControl.onButtonWasPushed(2); //  
		remoteControl.offButtonWasPushed(2); //    
		System.out.println(remoteControl);
		remoteControl.undoButtonWasPushed(); //    
		
		System.out.println();
		
		remoteControl.onButtonWasPushed(3); //  
		System.out.println(remoteControl);
		remoteControl.undoButtonWasPushed(); //  
	}

}

6.出力：

Living Room ceiling fan is on high
Living Room ceiling fan is off

------ Remote Control ------
[slot 0] command.LightOnCommand    command.LightOffCommand
[slot 1] command.LightOnCommand    command.LightOffCommand
[slot 2] command.CeilingFanHighCommand    command.CeilingFanOffCommand
[slot 3] command.CeilingFanMediumCommand    command.CeilingFanOffCommand
[slot 4] command.StereoOnWithCDCommand    command.StereoOffCommand
[slot 5] command.NoCommand    command.NoCommand
[slot 6] command.NoCommand    command.NoCommand

Living Room ceiling fan is on high

Living Room ceiling fan is on medium

------ Remote Control ------
[slot 0] command.LightOnCommand    command.LightOffCommand
[slot 1] command.LightOnCommand    command.LightOffCommand
[slot 2] command.CeilingFanHighCommand    command.CeilingFanOffCommand
[slot 3] command.CeilingFanMediumCommand    command.CeilingFanOffCommand
[slot 4] command.StereoOnWithCDCommand    command.StereoOffCommand
[slot 5] command.NoCommand    command.NoCommand
[slot 6] command.NoCommand    command.NoCommand

Living Room ceiling fan is on high

残りのコードのダウンロード: http://download.csdn.net/detail/u012515223/7507147

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