叫号机NumberMachine

package com.mth.bank;
/*
 * 
 * 叫号机
 * 
 * */
public class NumberMachine {
	private NumberManager commManager = new NumberManager();// 普通用户号码管理
	private NumberManager expressManager = new NumberManager();// 快速用户号码管理
	private NumberManager vipManager = new NumberManager();// Vip用户号码管理

	public NumberManager getCommManager() {
		return commManager;
	}

	public NumberManager getExpressManager() {
		return expressManager;
	}

	public NumberManager getVipManager() {
		return vipManager;
	}

	// 单例 NumberMachine对象只能有一个

	private static NumberMachine machine = new NumberMachine();
	//构造方法私有化
	private NumberMachine() {
	}
	//提供一个公开的方法来获得对象
	public static NumberMachine getInstance() {

		return machine;
	}
}