闭锁CountDownLatch的源码实现介绍

package com.nine.concurrent;

import java.util.concurrent.CountDownLatch;

public class CountDownLatchDemo {
   public long timeTasks(int nThreads,final Runnable task) {
       
     final CountDownLatch startGate = new CountDownLatch(1) ;
     final CountDownLatch enddGate = new CountDownLatch(nThreads);
     for(int i = 0;i<nThreads;i++){
         Thread t = new Thread(){
             
             @Override
            public void run() {
                 try {
                    startGate.await();
                    
                    
                      try{
                          task.run(); 
                     }finally{
                         enddGate.countDown();     
                     }
                      
                } catch (InterruptedException e) {
                    
                    e.printStackTrace();
                }
            }
         };
         
        t.start(); 
     }   
       
     long start = System.nanoTime();
     startGate.countDown();
     try {
        enddGate.await();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
     long end = System.nanoTime();
       
    return end-start;
}    
}