Command.java

package com.cheng.zenofdesignpatterns.patterns.command.common;

/**
 * 抽象命令类
 */
public abstract class Command {

	//定义一个子类的全局共享变量
	protected final Receiver receiver;

	// 每个命令类都必须有一个执行命令的方法
	public abstract void execute();

	//实现类必须定义一个接收者
	public Command(Receiver _receiver){
		this.receiver = _receiver;
	}
}