- package com.company.section4;
- /**
- * @author cbf4Life cbf4life@126.com
- * I'm glad to share my knowledge with you all.
- */
- public abstract class Command {
- //定义一个子类的全局共享变量
- protected final Receiver receiver;
- //实现类必须定义一个接收者
- public Command(Receiver _receiver){
- this.receiver = _receiver;
- }
- //每个命令类都必须有一个执行命令的方法
- public abstract void execute();
- }