命令模式 - ToB企服应用市场:ToB评测及商务社交产业平台

/**
* @author 长名06
* @version 1.0
*/
public interface Command {
public void execute();
public void undo();
}
/**
* @author 长名06
* @version 1.0
*/
public class LightOffCommand implements Command{
private LightReceiver receiver;
public LightOffCommand(LightReceiver receiver){
this.receiver = receiver;
}
@Override
public void execute() {
receiver.off();
}
@Override
public void undo() {
receiver.on();
}
}
/**
* @author 长名06
* @version 1.0
*/
public class LightOnCommand implements Command{
//组合实际命令的执行者(命令接收者)
private LightReceiver receiver;
public LightOnCommand(LightReceiver receiver){
this.receiver = receiver;
}
@Override
public void execute() {
receiver.on();
}
@Override
public void undo() {
receiver.off();
}
}
/**
* 没有任何命令，即空执行用于初始化每个按钮调用空命令时，对象什么都不做
* 其实这也是一种设计模式，可以省掉空判断
* @author 长名06
* @version 1.0
*/
public class NoCommand implements Command{
@Override
public void execute() {
}
@Override
public void undo() {
}
}
/**
* @author 长名06
* @version 1.0
*/
public class TVOffCommand implements Command{
private TVReceiver tvReceiver;
public TVOffCommand(TVReceiver tvReceiver){
this.tvReceiver = tvReceiver;
}
@Override
public void execute() {
tvReceiver.off();
}
@Override
public void undo() {
tvReceiver.on();
}
}
/**
* @author 长名06
* @version 1.0
*/
public class TVOnCommand implements Command{
private TVReceiver tvReceiver;
public TVOnCommand(TVReceiver tvReceiver){
this.tvReceiver = tvReceiver;
}
@Override
public void execute() {
tvReceiver.on();
}
@Override
public void undo() {
tvReceiver.off();
}
}
/**
* @author 长名06
* @version 1.0
*/
public class LightReceiver {
public void on(){
System.out.println("电灯打开");
}
public void off(){
System.out.println("电灯关闭");
}
}
/**
* @author 长名06
* @version 1.0
*/
public class TVReceiver {
public void on(){
System.out.println("电视打开了");
}
public void off(){
System.out.println("电视关闭了");
}
}
/**
* @author 长名06
* @version 1.0
*/
public class RemoterController {
//开按钮命令数组
private Command[] onCommands;
//关按钮命令数组
private Command[] offCommands;
//执行撤销命令按钮
private Command undoCommand;
/**
* 构造方法，传入指令数组的长度，以及数组中初始的指令类型
*/
public RemoterController(){
//先赋值，后使用
onCommands = new Command[5];
offCommands = new Command[5];
for (int i = 0; i < 5; i++) {
onCommands[i] = new NoCommand();
offCommands[i] = new NoCommand();
}
}
/**
* 根据数组下标设置特定打开指令
* @param i
*/
public void setCommand(int i,Command onCommand,Command offCommand){
if(i < 0 || i >= onCommands.length){
throw new IndexOutOfBoundsException();
}
onCommands[i] = onCommand;
offCommands[i] = offCommand;
}
public void onButtonWasPushed(int no){
//找到按下的开按钮对应的命令，并执行命令
onCommands[no].execute();
//记录这次操作，用于撤销
undoCommand = onCommands[no];
}
public void offButtonWasPushed(int no){
//找到按下的关按钮对应的命令，并执行命令
offCommands[no].execute();
//记录这次操作，用于撤销
undoCommand = offCommands[no];
}
public void undoButtonWasPushed(){
undoCommand.undo();
}
}
public class Client {
public static void main(String[] args) {
RemoterController remoterController = new RemoterController();
//创建电灯接收者
LightReceiver lightReceiver = new LightReceiver();
//创建电灯的开指令
LightOffCommand lightOffCommand = new LightOffCommand(lightReceiver);
//创建电灯的关指令
LightOnCommand lightOnCommand = new LightOnCommand(lightReceiver);
//将电灯的开关指令，设置到遥控器中
remoterController.setCommand(0,lightOnCommand,lightOffCommand);
System.out.println("按下电灯的开按钮");
remoterController.onButtonWasPushed(0);
System.out.println("按下电灯的关按钮");
remoterController.offButtonWasPushed(0);
System.out.println("按下遥控器的撤销按钮");
remoterController.undoButtonWasPushed();
//创建电视接收者
TVReceiver tvReceiver = new TVReceiver();
//创建电视打开指令
TVOnCommand tvOnCommand = new TVOnCommand(tvReceiver);
//创建电视关闭指令
TVOffCommand tvOffCommand = new TVOffCommand(tvReceiver);
//将电视的开关指令，设置到遥控器中
remoterController.setCommand(1,tvOnCommand,tvOffCommand);
System.out.println("按下电视的开按钮");
remoterController.onButtonWasPushed(1);
System.out.println("按下电视的关按钮");
remoterController.offButtonWasPushed(1);
System.out.println("按下遥控器的撤销按钮");
remoterController.undoButtonWasPushed();
}
}

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