/*
 *	MeasureThreadSleep.java
 */

/* Sun JDK 1.4.2 or later is required to compile and run this program. */

import sun.misc.Perf;


public class MeasureThreadSleep
{
	public static void main(String[] args)
	{
		if (args.length == 0 || args.length > 2)
		{
			printUsageAndExit();
		}
		int millis = Integer.parseInt(args[0]);
		int nanos = -1;
		if (args.length== 2)
		{
			nanos = Integer.parseInt(args[1]);
		}

		Perf perf = Perf.getPerf(); // may throw SecurityException
		long ticksPerSecond = perf.highResFrequency();
		for (int i = 0; i < 10; i++)
		{
			try
			{
				long start;
				long end;
				if (nanos != -1)
				{
					start = (perf.highResCounter() * 1000) / ticksPerSecond;
					Thread.sleep(millis, nanos);
					end = (perf.highResCounter() * 1000) / ticksPerSecond;
				}
				else
				{
					start = (perf.highResCounter() * 1000) / ticksPerSecond;
					Thread.sleep(millis);
					end = (perf.highResCounter() * 1000) / ticksPerSecond;
				}
				out("measured duration (ms): " + (end - start));
			}
			catch (InterruptedException e)
			{
				// IGNORE
			}
		}
	}


	private static void printUsageAndExit()
	{
		out("MeasureThreadSleep: usage:");
		out("\tjava MeasureThreadSleep <milliseconds> [<nanoseconds>]");
		System.exit(1);
	}


	private static void out(String strMessage)
	{
		System.out.println(strMessage);
	}


}



/*** MeasureThreadSleep.java ***/