package com.zuidaima.thread;

import java.util.Random;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * 
 * ReentrantReadWriteLock读写锁的demo
 * @author luoy
 *
 */
public class ReadWriteLockDemo {

	public static void main(String[] args) {
		final Demo1 demo = new Demo1();
		//测试读取数据方法
		for(int i=0;i<3;i++){
			new Thread(){
				public void run(){
					while(true){
						demo.get();
					}
				}
			}.start();
		}
		
		//测试写数据方法
		for(int i=0;i<3;i++){
			new Thread(){
				public void run(){
					while(true){
						demo.put(new Random().nextInt(10000));
					}
				}
			}.start();
		}
	}	
}

class Demo1{
	private Object data = null;//模拟数据
	private ReentrantReadWriteLock RWL = new ReentrantReadWriteLock();// 创建一个读写锁对象
	
	//读取数据方法
	public void get(){
		RWL.readLock().lock();//上读锁
		System.out.println(Thread.currentThread().getName()+" 这个时候只能读数据咯....");
		try {
			Thread.sleep((long)new Random().nextInt(10000));
		} catch (Exception e) {
			// TODO: handle exception
		}
		System.out.println(Thread.currentThread().getName()+" 发现可读数据--->:"+data);
		RWL.readLock().unlock();//释放读锁
	}
	
	//写数据方法
	public void put(Object data){
		RWL.writeLock().lock();//上写锁
		System.out.println(Thread.currentThread().getName()+" 这个时候不能写数据了...");
		try {
			Thread.sleep((long)new Random().nextInt(10000));
		} catch (Exception e) {
			// TODO: handle exception
		}
		this.data = data;
		System.out.println(Thread.currentThread().getName()+" 发现可读数据--->:"+data);
		RWL.writeLock().unlock();//释放写锁
	}
}