Consumer VS Producer

In the producer and consumer models, you must ensure the following:
1. Only one producer can produce data at a time.
2. Only one consumer can consume at a time.
3. The producer cannot consume the product at the same time.
4 when the message queue is full, the producer cannot continue production.
5 when the message queue is empty, the consumer cannot continue to consume

package ying.threadWait;import java.util.Vector;public class TestConsumer {public static void main(String[] args) { WareHouse warehouse = new WareHouse(0) ; Producer pro1 = new Producer(15 , warehouse) ;  Consumer cust1 = new Consumer(30 , warehouse) ;  Consumer cust2 = new Consumer(20 , warehouse) ;  Consumer cust3 = new Consumer(15 , warehouse) ;  pro1.start() ;  cust1.start() ; cust2.start() ; cust3.start() ; System.out.println("Bye"); }}class WareHouse { public int cur_size ; public final static int max_size = 50 ; public WareHouse() { }public WareHouse(int size) { this.cur_size = size ; }public synchronized void produce(int produceNum) { while (produceNum + cur_size > max_size) { System.out.println("The quantity of product to produce is " + produceNum + " which is over the remaining storage limit : " + (max_size - cur_size));try {System.out.println("Producer " + Thread.currentThread().getName() + " waits"); wait() ;} catch (InterruptedException e) {e.printStackTrace();} }cur_size += produceNum ; System.out.println(Thread.currentThread().getName() + " has produced " + produceNum + " pieces of product."); notifyAll() ; }public synchronized void consume(int needNum) { while (needNum > cur_size) { try {System.out.println("Consumer " + Thread.currentThread().getName() + " waits"); wait() ;} catch (InterruptedException e) {e.printStackTrace();} }cur_size -= needNum ; System.out.println("The customer has consumed " + needNum + " pieces of product.");notifyAll() ; }}class Producer extends Thread { private int produceNum ; private WareHouse warehouse ; Producer(int num , WareHouse house) { this.produceNum = num ;  this.warehouse = house ; } public void run() { while (true) { warehouse.produce(produceNum) ; } }}

class Consumer extends Thread { private int needNum ; private WareHouse warehouse ; Consumer(int num , WareHouse warehouse) { this.needNum = num ; this.warehouse = warehouse ; }public void run() { warehouse.consume(needNum) ; }}

When free can refer to: http://www.blogjava.net/amigoxie/archive/2007/04/11/110006.html