java多线程经典案例-多生产者多消费者模式

多个线程插入数据，多个线程删除数据的经典例子。

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 等待唤醒机制的最经典实例。 生产消费者模式 多生产者多消费者模式 。
 * 
 * 1,出现多生产，多消费问题？？？if(flag)-->while(flag)
 * 
 * 2,多生产者多消费者模式的等待唤醒机制中的死锁？？？notifyAll()
 * 
 * 3,notifyAll();唤醒所用的线程，浪费资源？？？ 使用Luck和 Condition实现一个方锁两个监视器
 * 
 */
public class ThreadDemo {
	public static void main(String[] args) {
		BoundedBuffer r = new BoundedBuffer();
		Producter in = new Producter(r);
		Consumer out = new Consumer(r);
		
		Thread tin = new Thread(in);
		Thread tin1 = new Thread(in);

		Thread tout = new Thread(out);
		Thread tout1 = new Thread(out);

		tin.start();
		tin1.start();
		tout.start();
		tout1.start();
	}
}

class BoundedBuffer {
	final Lock lock = new ReentrantLock();
	final Condition notFull = lock.newCondition();
	final Condition notEmpty = lock.newCondition();

	final Object[] items = new Object[10];
	int putptr, takeptr, count;

	public void put(Object x) throws InterruptedException {
		lock.lock();
		try {
			while (count == items.length)
				notFull.await();
			items[putptr] = x;
			if (++putptr == items.length)
				putptr = 0;
			++count;
			notEmpty.signal();
		} finally {
			System.out.println("生產結束 現在個數="+count);
			bl(items);
			System.out.println("");
			lock.unlock();
		}
	}

	public Object take() throws InterruptedException {
		lock.lock();
		try {
			while (count == 0)
				notEmpty.await();
			Object x = items[takeptr];
			items[takeptr]="[ ]";
			if (++takeptr == items.length)
				takeptr = 0;
			--count;
			notFull.signal();
			return x;
		} finally {
			System.out.println("消費結束 現在個數="+count);
			bl(items);
			System.out.println("");
			lock.unlock();
		}
	}
	
	
	private void bl(Object[] items) {
		for (int i = 0; i < items.length; i++) {
			System.out.print("元素有:");
			System.out.print(i+"="+items[i]+" ");
		}
	}
}

class Producter implements Runnable {
	BoundedBuffer r;

	Producter(BoundedBuffer r) {
		this.r = r;
	}

	public void run() {
		while (true) {
			try {
				r.put("烤鸭");
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}

class Consumer implements Runnable {
	BoundedBuffer r;
	Consumer(BoundedBuffer r) {
		this.r = r;
	}

	public void run() {
		while (true) {
			try {
				r.take();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}