黑马程序员-java 7K面试题之银行业务调度系统

package cn.itcast.bank;

import java.util.ArrayList;

public class NumberManager {
	private int lastNumber=1;
	private ArrayList<Integer> queueNumber=new ArrayList<Integer>();
	public synchronized int generateNewManager(){
		queueNumber.add(lastNumber);
		return lastNumber++;
	}
	public synchronized Integer fetchServiceNumber(){
		Integer number=null;
		if(queueNumber.size()>0){
			number=queueNumber.remove(0);
		}
		return number;
	}
}

package cn.itcast.bank;

public class NumberMachine {
	private NumberManager commonManager=new NumberManager();
	private NumberManager expressManager=new NumberManager();
	private NumberManager vipManager=new NumberManager();
	public NumberManager getCommonManager(){
		return commonManager;
	}
	public NumberManager getExpressManager(){
		return expressManager;
	}
	public NumberManager getVipManager(){
		return vipManager;
	}
	//用单例设计模式实现取号机器NumberMachine，这样commonManager、expressManager、vipManager也内存中也就分别只有一个对象，各自按顺序生成号码。
	private NumberMachine(){}
	public static NumberMachine getInstance(){
		return instance;
	}
	private static NumberMachine instance=new NumberMachine();
}

package cn.itcast.bank;
/*
 * 业务类型枚举值
 */
public enum CustomerType {
	COMMON,EXPRESS,VIP;
	public String toString(){
		switch(this){
		case COMMON:
			return "普通";
		case EXPRESS:
			return "快速";
		case VIP:
			return name();
		}
		return null;
	}
}

package cn.itcast.bank;

public class Constants {
	//最大和最小服务时间
	public static int MAX_SERVICE_TIME=10000;
	public static int MIN_SERVICE_TIME=1000;
	//普通客户到来的时间间隔
	public static int COMMON_CUSTOMER_INTERVAL_TIME=1;
}

package cn.itcast.bank;
/*
 * 业务窗口类
 */
import java.util.Random;
import java.util.concurrent.Executors;

public class ServiceWindow {
	private CustomerType type=CustomerType.COMMON;
	public void setType(CustomerType type) {
		this.type = type;
	}
	private int windowId=1;
	public void setWindowId(int windowId) {
		this.windowId = windowId;
	}
	public void start(){
		Executors.newSingleThreadExecutor().execute(new Runnable(){
			@Override
			public void run(){
				while(true){
					switch(type){
					case COMMON:
						commonService();
						break;
					case EXPRESS:
						expressService();
						break;
					case VIP:
						vipService();
						break;
					}
				}
			}
		});	
	}
	private void commonService() {
		String windowName="第"+windowId+"号"+type+"窗口";
		Integer number=NumberMachine.getInstance().getCommonManager().fetchServiceNumber();
		System.out.println(windowName+"正在获取普通任务！");		
		if(number!=null){
			System.out.println(windowName+"为第"+number+"号普通客户服务！");
			//普通窗口的服务时间是随机的，在最大服务时间与最小服务时间之间
			int maxRand=Constants.MAX_SERVICE_TIME-Constants.MIN_SERVICE_TIME;
			long serviceTime=new Random().nextInt(maxRand)+1+Constants.MIN_SERVICE_TIME;
			try {
				Thread.sleep(serviceTime);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println(windowName+"为第"+number+"个普通客户完成服务，耗时"+serviceTime/1000+"秒");
		}
		else{
			System.out.println(windowName+"没有取到普通任务，先休息1秒钟！");
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	private void expressService() {
		String windowName="第"+windowId+"号"+type+"窗口";
		Integer number=NumberMachine.getInstance().getExpressManager().fetchServiceNumber();
		System.out.println(windowName+"正在获取快速任务！");		
		if(number!=null){
			System.out.println(windowName+"为第"+number+"号快速客户服务！");
			//快速窗口的服务时间是最短的
			long serviceTime=Constants.MIN_SERVICE_TIME;
			try {
				Thread.sleep(serviceTime);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println(windowName+"为第"+number+"个"+type+"客户完成服务，耗时"+serviceTime/1000+"秒");
		}
		else{
			System.out.println(windowName+"没有取到快速任务！");
			//快速窗口没有任务时可以为普通客户服务
			commonService();
		}
	}
	private void vipService() {
		String windowName="第"+windowId+"号"+type+"窗口";
		Integer number=NumberMachine.getInstance().getVipManager().fetchServiceNumber();
		System.out.println(windowName+"正在获取VIP任务！");		
		if(number!=null){
			System.out.println(windowName+"为第"+number+"号VIP客户服务！");
			//VIP窗口的服务时间也是随机的，在最大服务时间与最小服务时间之间
			int maxRand=Constants.MAX_SERVICE_TIME-Constants.MIN_SERVICE_TIME;
			long serviceTime=new Random().nextInt(maxRand)+1+Constants.MIN_SERVICE_TIME;
			try {
				Thread.sleep(serviceTime);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println(windowName+"为第"+number+"个"+type+"客户完成服务，耗时"+serviceTime/1000+"秒");
		}
		else{
			System.out.println(windowName+"没有取到VIP任务!");
			//VIP窗口没有任务时可以为普通客户服务
			commonService();
		}
	}	
}

package cn.itcast.bank;

import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

public class MainClass {

	public static void main(String[] args) {
		//产生4个普通窗口
		for(int i=1;i<5;i++){
			ServiceWindow commonWindow=new ServiceWindow();
			commonWindow.setWindowId(i);
			commonWindow.start();
		}
		//产生一个快速窗口
		ServiceWindow expressWindow=new ServiceWindow();
		expressWindow.setType(CustomerType.EXPRESS);
		expressWindow.start();
		//产生一个VIP窗口
		ServiceWindow vipWindow=new ServiceWindow();
		vipWindow.setType(CustomerType.VIP);
		vipWindow.start();
		//普通客户拿号
		Executors.newScheduledThreadPool(1).scheduleAtFixedRate(
				new Runnable(){
					@Override
					public void run() {
						Integer number=NumberMachine.getInstance().getCommonManager().generateNewManager();
						System.out.println("第"+number+"号普通客户正在等待服务！");
					}					
				}, 
				0, 
				Constants.COMMON_CUSTOMER_INTERVAL_TIME, 
				TimeUnit.SECONDS);
		//快速客户拿号
		Executors.newScheduledThreadPool(1).scheduleAtFixedRate(
				new Runnable(){
					@Override
					public void run() {
						Integer number=NumberMachine.getInstance().getExpressManager().generateNewManager();
						System.out.println("第"+number+"号快速客户正在等待服务！");
					}
				}, 
				0, 
				Constants.COMMON_CUSTOMER_INTERVAL_TIME*3, 
				TimeUnit.SECONDS);
		//VIP客户拿号
		Executors.newScheduledThreadPool(1).scheduleAtFixedRate(
				new Runnable(){
					@Override
					public void run() {
						//下面这2句不应该分开执行，应该作为一个整体执行，但因generateNewManager()方法中加锁，此外再加锁易造成死锁
						Integer number=NumberMachine.getInstance().getVipManager().generateNewManager();
						System.out.println("第"+number+"号VIP客户正在等待服务！");
					}					
				}, 
				0, 
				Constants.COMMON_CUSTOMER_INTERVAL_TIME*6, 
				TimeUnit.SECONDS);
	}

}