问Java中的并发编程。尝试模拟一组结账计数器

EN

package Supermarket;

import java.util.*;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

public class Checkout implements Runnable
{
    public BlockingQueue<Integer> item_queue = new ArrayBlockingQueue<Integer>(10);

    public int checkout_number;
    public int item;

    public Random random;

    public Checkout(int checkout_number, BlockingQueue<Integer> item_queue)
    {
        this.checkout_number = checkout_number;
        this.item_queue = item_queue;

        random = new Random();
        System.out.println("\nCheckout Counter Number: "+checkout_number);
    }

    public void run()
    {
        while(true)
        {           
            if(item == -1)
            {
                System.out.println("Consumer finished");
                break;
            }
            else
            {
                try 
                {
                    item = item_queue.take();
                } 
                catch (InterruptedException e) 
                {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                System.out.println("\nConsumer has taken item ==> "+item);
                System.out.println("Scanning item");

                try 
                {
                    Thread.sleep(random.nextInt(5000));
                } 
                catch (InterruptedException e)
                {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }

}

    package Supermarket;

import java.util.*;
import java.util.concurrent.*;

public class Customer implements Runnable
{

    public int item;
    public int customer_number;
    public int i;
    public int item_count;

    public Random random = new Random();
    public BlockingQueue<Integer> item_queue = new ArrayBlockingQueue<Integer>(10);

    public Customer(int customer_number, BlockingQueue<Integer> item_queue)
    {
        this.customer_number = customer_number;
        this.item_queue = item_queue;
    }

    public void run()
    {
        item_count = random.nextInt(5);

        System.out.println("I am customer Number: "+customer_number+" and I have "+item_count+" items");

        for(i=0; i<item_count; i++)
        {
            try 
            {
                item_queue.put(random.nextInt(10));
            } 
            catch (InterruptedException e) 
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        try 
        {
            item_queue.put(-1);
        } 
        catch (InterruptedException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

package Supermarket;

import java.util.concurrent.*;
import java.util.*;

public class Driver 
{
    public static BlockingQueue<Integer> item_queue = new ArrayBlockingQueue<Integer>(10);

    public static Random random = new Random();

    public static int customer_count;
    public static int checkout_count;
    public static int i;

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        customer_count = random.nextInt(4)+1;
//      checkout_count = 5;

        System.out.println("Total Number of Customers: "+customer_count+"\n");

            for(i=0; i<customer_count; i++)
            {
                Customer customer = new Customer(i+1, item_queue);
                Thread customer_thread = new Thread(customer);
                customer_thread.start();
            }

//          for(i=0; i<=checkout_count; i++)
//          {
//              Checkout checkout = new Checkout(1, item_queue);
//              Thread checkout_thread = new Thread(checkout);
//              checkout_thread.start();
//          }

//      System.out.println("\n\nProgram Terminates!\n\n");
    }

}