黑马程序员——银行业务调度系统

 

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银行业务调度系统

1.  熟悉银行的业务。

银行有一个取号机，vip窗口，普通窗口，快速窗口。取号机取出的号码相当于客户，窗口需要叫号。可以把这个逻辑封装成一个对象NumberManager。

2.  创建号管理类NumberManager。

package cn.itheima.interview.bank;

import java.util.ArrayList;

import java.util.List;

public class NumberManager {

    private int lastNumber = 1;

    // 在创建对象的时候尽量使用父类或者接口指向子类对象，不仅灵活而且看起来比较专业。

    private List<Integer> queue = new ArrayList<Integer>();

 

    // 下面这两个方法，在程序运行的时候，是由两个不同的线程调用。它们操作了同一个变量queue.

    // 所以用到synchronized关键字进行同步。

    public synchronized int generateNumber() {

       // 调用一次生成一个号码，把它加入队列中。然后再返回该值，让外界知道新客户来了。

       // lastNumber自增，如果再有下个用户来了，直接加入队列中，继续上述操作。

       queue.add(lastNumber);

       return lastNumber++;

    }

 

    public synchronized int fetchServiceNumber() {

       // 记住这种设计思想，从一个容器中取走（得到该值，并且容器删除该值）一个值。

       Integer number = null;

       if (queue.size() > 0) {

           number = queue.remove(0);

       }

       return number;

    }

}

3.  创建取号码的机器。

由于一个银行只有一个取号机器，采用单例设计模式。

package cn.itheima.interview.bank;

 

public class NumberMachine {

    private NumberManager commonManager;

    private NumberManager expressManager;

    private NumberManager vipManager;

 

    private NumberMachine() {

    }

//单例设计模式。

    private static NumberMachine instance = new NumberMachine();

    public static NumberMachine getInstance() {

       return instance;

    }

 

    public NumberManager getCommonManager() {

       return commonManager;

    }

 

    public NumberManager getExpressManager() {

       return expressManager;

    }

 

    public NumberManager getVipManager() {

       return vipManager;

    }

 

}

 

4.创建服务窗口。

package cn.itheima.interview.bank;

 

import java.util.Random;

import java.util.concurrent.Executors;

 

public class ServiceWindow {

    private CustomerType type = CustomerType.COMMON;

    private int number = 1;

 

    public void setType(CustomerType type) {

       this.type = type;

    }

 

    public void setWindowId(int number) {

       this.number = number;

    }

 

    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 vipService() {

              String windowName = "第" + number + "号" + type + "窗口";

              System.out.println(windowName + "开始准备获取任务！");

              Integer serviceNum = NumberMachine.getInstance()

                     .getCommonManager().fetchServiceNumber();

              if (serviceNum != null) {

                  System.out.println(windowName + "开始为第" + serviceNum

                         + "号vip客户服务");

 

                  long startTime = System.currentTimeMillis();

                  int randomTime = Constants.MAX_SERVICE_TIME

                         - Constants.MIN_SERVICE_TIME;

                  long serviceTime = new Random().nextInt(randomTime) + 1

                         + Constants.MIN_SERVICE_TIME;

                  try {

                     Thread.sleep(serviceTime);

                  } catch (InterruptedException e) {

                     e.printStackTrace();

                  }

                  long costTime = System.currentTimeMillis() - startTime;

 

                  System.out.println(windowName + "窗口完成第" + number

                         + "号快速vip的服务，共耗时" + costTime / 1000 + "秒");

              } else {

                  System.out.println(windowName + "没有取得vip任务");

                  commonService();

              }

           }

 

           private void expressService() {

              String windowName = "第" + number + "号" + type + "窗口";

              System.out.println(windowName + "开始准备获取任务！");

              Integer serviceNum = NumberMachine.getInstance()

                     .getCommonManager().fetchServiceNumber();

              if (serviceNum != null) {

                  System.out.println(windowName + "开始为第" + serviceNum

                         + "号快速客户服务");

 

                  long startTime = System.currentTimeMillis();

                  int randomTime = Constants.MAX_SERVICE_TIME

                         - Constants.MIN_SERVICE_TIME;

                  long serviceTime = new Random().nextInt(randomTime) + 1

                         + Constants.MIN_SERVICE_TIME;

                  try {

                     Thread.sleep(serviceTime);

                  } catch (InterruptedException e) {

                     e.printStackTrace();

                  }

                  long costTime = System.currentTimeMillis() - startTime;

 

                  System.out.println(windowName + "窗口完成第" + number

                         + "号快速用户的服务，共耗时" + costTime / 1000 + "秒");

              } else {

                  System.out.println(windowName + "没有取得快速任务");

                  commonService();

              }

 

           }

 

           private void commonService() {

              String windowName = "第" + number + "号" + type + "窗口";

              System.out.println(windowName + "开始准备获取任务！");

              Integer serviceNum = NumberMachine.getInstance()

                     .getCommonManager().fetchServiceNumber();

              if (serviceNum != null) {

                  System.out.println(windowName + "开始为第" + serviceNum

                         + "号普通客户服务");

 

                  long startTime = System.currentTimeMillis();

                  int randomTime = Constants.MAX_SERVICE_TIME

                         - Constants.MIN_SERVICE_TIME;

                  long serviceTime = new Random().nextInt(randomTime) + 1

                         + Constants.MIN_SERVICE_TIME;

                  try {

                     Thread.sleep(serviceTime);

                  } catch (InterruptedException e) {

                     e.printStackTrace();

                  }

                  long costTime = System.currentTimeMillis() - startTime;

 

                  System.out.println(windowName + "窗口完成第" + number

                         + "号普通用户的服务，共耗时" + costTime / 1000 + "秒");

              } else {

                  System.out.println(windowName + "没有取得普通任务，空闲1秒");

                  try {

                     Thread.sleep(1000);

                  } catch (InterruptedException e) {

                     e.printStackTrace();

                  }

              }

 

           }

 

       });

    }

 

}

5.  创建测试类包含用户的取号。

 

package cn.itheima.interview.bank;

import java.util.concurrent.Executors;

import java.util.concurrent.TimeUnit;

 

public class MainClass {

 

    public static void main(String[] args) {

       // 产生4个普通用户

       for (int i = 1; i < 5; i++) {

           ServiceWindow commonWindow = new ServiceWindow();

           commonWindow.setType(CustomerType.COMMON);

           commonWindow.setWindowId(i);

           commonWindow.start();

       }

       // 产生1个快速用户

       ServiceWindow expressWindow = new ServiceWindow();

       expressWindow.setType(CustomerType.EXPRESS);

       expressWindow.setWindowId(1);

       expressWindow.start();

       // 产生1个vip用户

       ServiceWindow vipWindow = new ServiceWindow();

       vipWindow.setType(CustomerType.EXPRESS);

       vipWindow.setWindowId(1);

       vipWindow.start();

 

       // 普通客户拿号

       Executors.newScheduledThreadPool(1).scheduleAtFixedRate(new Runnable() {

           public void run() {

              Integer serviceNumber = NumberMachine.getInstance()

                     .getCommonManager().generateNumber();

              /**

               * 采用logger方式，无法看到直观的运行效果，因为logger.log方法内部并不是直接把内容打印出出来，

               * 而是交给内部的一个线程去处理，所以，打印出来的结果在时间顺序上看起来很混乱。

               */

              // logger.info("第" + serviceNumber + "号普通客户正在等待服务！");

              System.out.println("第" + serviceNumber + "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() {

           public void run() {

              Integer serviceNumber = NumberMachine.getInstance()

                     .getExpressManager().generateNumber();

              System.out.println("第" + serviceNumber + "号快速客户正在等待服务！");

           }

       }, 0, Constants.COMMON_CUSTOMER_INTERVAL_TIME * 2, TimeUnit.SECONDS);

 

       // VIP客户拿号

       Executors.newScheduledThreadPool(1).scheduleAtFixedRate(new Runnable() {

           public void run() {

              Integer serviceNumber = NumberMachine.getInstance()

                     .getVipManager().generateNumber();

              System.out.println("第" + serviceNumber + "号VIP客户正在等待服务！");

           }

       }, 0, Constants.COMMON_CUSTOMER_INTERVAL_TIME * 6, TimeUnit.SECONDS);

    }

}