如何对一个无限循环Java nio watchservice程序进行基准测试

Question

我有一个无限轮询循环使用java.nio.file.WatchService寻找新的文件。在循环中我有固定的线程池执行器服务并发处理文件。

当轮询服务继续运行时，我如何对一批文件(例如10/n个文件)的处理时间进行基准测试?我能够在可运行类中的每个文件计时，但如何获得批处理时间?

Answer 1

应该这样做:

// inside the listener for the WatchService
final MyTimer t = new MyTimer(); // takes current time, initialized to 0 tasks
for (Change c : allChanges) {
   t.incrementTaskCount(); // synchronized
   launchConcurrentProcess(c, t);
}
// inside your processor, after processing a change
t.decrementTaskCount(); // also synchronized
// inside MyTimer
public void synchronized decrementTaskCount() {       
   totalTasks --;
   // depending on your benchmarking needs, you can do different things here
   // I am printing max time only (= end of last), but min/max/avg may also be nice
   if (totalTasks == 0) {
      System.err.println("The time spent on this batch was " 
          + System.currentTimeMillis() - initialTime);
   }
}