StampedLock如何使用？

package constxiong.interview;

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

/**
 * 测试 StampedLock
 * @author ConstXiong
 */
public class TestStampedLock {

    private static final StampedLock sl = new StampedLock();
    
    private static volatile int count = 0;
    
    private static final Random r = new Random();
    
    public static void main(String[] args) {
        //启动 5个线程写计数,95 个线程读计数,
        for (int i = 0; i < 100; i++) {
            if (i % 20 == 0) {
                new Thread(() -> {
                    try {
                        Thread.sleep(r.nextInt(10));
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName() + " 计数新增 1 :" + add());
                }).start();
            } else {
                new Thread(() -> {
                    try {
                        Thread.sleep(r.nextInt(10));
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName() + " 读计数:" + read());
                }).start();
            }    
        }
    }
    
    /**
     * 读取计数
     * @return
     */
    private static int read() {
        int r;
        long stamp = sl.tryOptimisticRead();
        r = count;
        if (!sl.validate(stamp)) {
            stamp = sl.readLock();
            try {
                r = count;
            } finally {
                sl.unlockRead(stamp);
            }
        }
        return r; 
    }
    
    /**
     * 计数加 1
     */
    private static int add() {
        long stamp = sl.writeLock();
        try {
            count++;
        } finally {
            sl.unlockWrite(stamp);
        }
        return count;
    }
    
}