//Command声明执行操作的接口

abstract class Command {

protected Receiver receiver;

public Command(Receiver receiver) {

this.receiver = receiver;

}

public abstract void execute();

}

//creteCommand将一个接收者对象绑定于一个动作。调用接收者相应的操作，以实现Execute。

class CommandImpl extends Command {

public CommandImpl(Receiver receiver) {

super(receiver);

}

public void execute() {

receiver. receive ();

}

}

//Invoker要求该命令执行这个请求。

class Invoker {

private Command command;

public void setCommand(Command command) {

this.command = command;

}

public void execute() {

command.execute();

}

}

//Receiver知道如何实现与执行一个请求相关的操作。任何类都可能作为一个接收者。

class Receiver {

public void receive() {

System.out.println("This is Receive class!");

}

}

public class DS14_Command{

public static void main(String[] args) {

Receiver rec = new Receiver();

Command cmd = new CommandImpl(rec);

Invoker i = new Invoker();

i.setCommand(cmd);

i.execute();

}

}