设计模式-生产者消费者模式

生产者-消费者问题： 

生产者向产品区里放产品，当产品区里满了，生产者需要等待；消费者从产品区里取产品腾出容量，生产者可继续生产，当产品区里空了，需要等待生产者生产。

public class ProducerAndConsumer{    //创建缓冲区    private static Buffer buffer = new Buffer();    public static void main(String[] args)     {//创建生产者        Thread producer = new Thread(new Producer());//创建消费者        Thread consumer = new Thread(new Consumer());//开始生产        consumer.start();//开始消费        producer.start();    }    //消费者线程    static class Consumer implements Runnable    {        public void run(){            try{                while(true){//消费                    buffer.poll();                    Thread.sleep(1000));                }            }catch(InterruptedException ex){}        }    }    //生产者线程    static class Producer implements Runnable    {        public void run(){            try{                while(true){//生产                    buffer.push(new Random().nextInt(20));                    Thread.sleep(1000);                }            }catch(InterruptedException ex){}        }    }}//缓冲池class Buffer{    //创建锁    private static Lock lock = new ReentrantLock();    //条件1：缓冲池为空    private static Condition empty = lock.newCondition();    //条件2：缓冲池为满    private static Condition full = lock.newCondition();    //缓冲池大小    private static final int  size =  10;    //缓冲池    private Queue<Integer> queue = new LinkedList<Integer>();    //消费    public void poll(){        lock.lock();        try{            while(queue.size() == 0){                System.out.println("无产品可消费，等待生产者生产。");                empty.await();            }            int num = queue.poll();            System.out.println("出售商品:" + num);//通知生产者：仓库有位置了            full.signal();        }catch(InterruptedException ex){        }finally{            lock.unlock();        }    }    //生产    public void push(int num){        lock.lock();        try{//库存不能大于仓库额定容量：10            while(queue.size() == 10){                System.out.println("Wait for consumer:");                full.await();            }//商品入库            queue.offer(num);            System.out.println("生产商品:" + num);//通知消费者：商品已经来了            empty.signal();        }catch(InterruptedException ex){        }finally{            lock.unlock();        }    }}