设计模式 - 命令模式(command pattern) 多命令 具体解释

命令模式(command pattern) 多命令 具体解释

本文地址: http://blog.****.net/caroline_wendy

參考命令模式: http://blog.****.net/caroline_wendy/article/details/31379977

具体步骤:

1. 多命令, 把未使用的命令, 初始化为空对象(NoCommand), 依据參数(slot), 选择输出命令.

/**
 * @time 2014年6月16日
 */
package command;

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

	Command[] onCommands; //开
	Command[] offCommands; //关

	public RemoteControl() {
		onCommands = new Command[7];
		offCommands = new Command[7];

		Command noCommand = new NoCommand();

		for (int i=0; i<7; ++i) { //初始化
			onCommands[i] = noCommand;
			offCommands[i] = 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();
	}

	public void offButtonWasPushed(int slot) {
		offCommands[slot].execute();
	}

	public String toString() {
		StringBuffer stringBuffer = new StringBuffer();
		stringBuffer.append("\n------ Remote Control ------\n");
		for (int i=0; i<onCommands.length; ++i) {
			stringBuffer.append("[slot " + i + "] " + onCommands[i].getClass().getName()
				+ "    " + offCommands[i].getClass().getName() + "\n");
		}

		return stringBuffer.toString();
	}
}

2. 空命令(NoCommand)对象, 继承命令接口.

package command;

public class NoCommand implements Command {
	public void execute() { }
}

3. 測试对象, 分别给多命令赋值(setCommand), 通过參数(slot)调用.

/**
 * @time 2014年6月16日
 */
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);

		CeilingFanOnCommand ceilingFanOn = new CeilingFanOnCommand(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, ceilingFanOn, ceilingFanOff);
		remoteControl.setCommand(3, stereoOnWithCD, stereoOffCommand);

		System.out.println(remoteControl);

		remoteControl.onButtonWasPushed(0);
		remoteControl.offButtonWasPushed(0);
		remoteControl.onButtonWasPushed(1);
		remoteControl.offButtonWasPushed(1);
		remoteControl.onButtonWasPushed(2);
		remoteControl.offButtonWasPushed(2);
		remoteControl.onButtonWasPushed(3);
		remoteControl.offButtonWasPushed(3);
	}

}

4. 输出:

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

Living Room Light is on
Living Room Light is off
Kitchen Light is on
Kitchen Light is off
Living Room ceiling fan is on high
Living Room ceiling fan is off
Living Room stereo is on
Living Room stereo is set for CD input
Living Room Stereo volume set to 11
Living Room stereo is off

其余代码下载: http://download.****.net/detail/u012515223/7506695