Warnings Cleanup in java.util.<various> (more from hack day)

[Xueming Shen]

On 12/02/2011 02:32 PM, Martijn Verburg wrote:
> Hi Sherman,
>
> I think the original patch provider (Prasanna) was aiming at simply 
> removing the deprecation warning.  Interesting point on the 
> performance aspect!
>
> Is performance for this class already measured in an OpenJDK test 
> somewhere?  Perhaps we could provide a test suite in this instance?

Hi Martijn,

No, I don't think we have a benchmark test case anywhere in OpenJDK to 
measure
this performance. I happened to take a quick look at the "calculation 
cost" of
dosToJavaTime() last month when working on that jar n-thread performance 
issue.

Here is a the result of a quick/dirty "non-benchmark" benchmark test 
case, which
suggests the proposed change is way too slow, this is only from the 
"speed" angle,
I would assume it probably also consumes more temporary (young-gen) memory.
So, the suggested approach appears not to be a good candidate to go in 
without
further tuning.

sherman at sherman-linux:~/Workspace/test$ java -server JavaDosTime
j2dt  :386
j2dt2 :1282
d2jt  :424
d2jt2 :1296
sherman at sherman-linux:~/Workspace/test$ java -client JavaDosTime
j2dt  :621
j2dt2 :1901
d2jt  :662
d2jt2 :2016

public class JavaDosTime {

     public static void main(String[] args) throws IOException {

         long tt0 = System.currentTimeMillis();
         int ii = 0;
         for (ii = 0; ii < 1000000; ii++) {
             long t = 10000 + ii;
             t= javaToDosTime(t);
         }
         long tt1 = System.currentTimeMillis();
         System.out.println("j2dt  :" + (tt1 - tt0));


         tt0 = System.currentTimeMillis();
         ii = 0;
         for (ii = 0; ii < 1000000; ii++) {
             long t = 10000 + ii;
             t= javaToDosTime2(t);
         }
         tt1 = System.currentTimeMillis();
         System.out.println("j2dt2 :" + (tt1 - tt0));


         tt0 = System.currentTimeMillis();
         ii = 0;
         for (ii = 0; ii < 1000000; ii++) {
             long t = 10000 + ii;
             t= dosToJavaTime(t);
         }
         tt1 = System.currentTimeMillis();
         System.out.println("d2jt  :" + (tt1 - tt0));


         tt0 = System.currentTimeMillis();
         ii = 0;
         for (ii = 0; ii < 1000000; ii++) {
             long t = 10000 + ii;
             t= dosToJavaTime2(t);
         }
         tt1 = System.currentTimeMillis();
         System.out.println("d2jt2 :" + (tt1 - tt0));

     }

     private static long javaToDosTime(long time){
         Date d = new Date(time);
         int year = d.getYear() + 1900;
         if (year < 1980) {
             return (1 << 21) | (1 << 16);
         }
         return (year - 1980) << 25 | (d.getMonth() + 1) << 21 |
                d.getDate() << 16 | d.getHours() << 11 | d.getMinutes() 
<< 5 |
                d.getSeconds() >> 1;
     }

     private static long javaToDosTime2(long time){
         Calendar cal = Calendar.getInstance();
         cal.setTimeInMillis(time);
         int year = cal.get(Calendar.YEAR);
         if (year < 1980) {
             return (1 << 21) | (1 << 16);
         }
         int month = cal.get(Calendar.MONTH) + 1;
         return (year - 1980) << 25
                 | month << 21
                 | cal.get(Calendar.DAY_OF_MONTH) << 16
                 | cal.get(Calendar.HOUR_OF_DAY) << 11
                 | cal.get(Calendar.MINUTE) << 5
                 | cal.get(Calendar.SECOND) >> 1;
      }

      private static long dosToJavaTime(long dtime) {
         Date d = new Date((int)(((dtime >> 25) & 0x7f) + 80),
                           (int)(((dtime >> 21) & 0x0f) - 1),
                           (int)((dtime >> 16) & 0x1f),
                           (int)((dtime >> 11) & 0x1f),
                           (int)((dtime >> 5) & 0x3f),
                           (int)((dtime << 1) & 0x3e));
         return d.getTime();
      }

      private static long dosToJavaTime2(long dtime) {
      Calendar cal = Calendar.getInstance();
      cal.set(Calendar.YEAR, (int) ((dtime >> 25) & 0x7f) + 1980);
      cal.set(Calendar.MONTH, (int) ((dtime >> 21) & 0x0f) - 1);
      cal.set(Calendar.DATE, (int) (dtime >> 16) & 0x1f);
      cal.set(Calendar.HOUR_OF_DAY, (int) (dtime >> 11) & 0x1f);
      cal.set(Calendar.MINUTE, (int) (dtime >> 5) & 0x3f);
      cal.set(Calendar.SECOND, (int) (dtime << 1) & 0x3e);
          return cal.getTimeInMillis();
      }

}





>
> Cheers,
> Martijn
>
> On Friday, 2 December 2011, Xueming Shen <xueming.shen at oracle.com 
> <mailto:xueming.shen at oracle.com>> wrote:
> >
> > The j.u.z.ZipEntry change should NOT be in as a warning cleanup. 
> Will need further
> > evaluation/measurement, for example from performance point of view, 
> the change
> > now creates a new Calendar instance instead of a Date object (Date 
> class uses a
> > singleton BaseCalendar for the calculation, if I remember correctly) 
> for each invocation.
> >
> > -Sherman
> >
> > On 12/02/2011 11:24 AM, Michael Barker wrote:
> >>
> >> Hi,
> >>
> >> We had some late submissions from our hack day participants.  2 more
> >> patches.  One (j.u.z.ZipEntry) is possibly a little more involved for
> >> a warnings fix.  It removes a usage of deprecated Date APIs in favour
> >> of Calendar.  However, the fix results in code that is very similar to
> >> Apache Harmony implementation.  The other is a couple of fixes for
> >> generics (j.u.j.Manifest).
> >>
> >> Thanks to:
> >> - Prasannaa
> >>
> >> Regards,
> >> Michael Barker
> >> mikeb2701
> >
> >