ansaurus

Question

Answer 1

+5 A:

Divide each by 1000. Since they are integers/longs, the decimal will be truncated. If they are in the same seconds, the values will be the same.

phantombrain 2010-03-01 08:15:05

... unless he needs to get rid of the rest of the date as well (from year down to minute), the question leaves room for interpretation ;)

Andreas_D 2010-03-01 08:20:23

I need to check whether they are from the same year/month/date/hour/minute/second. ;)

paul_sns 2010-03-01 08:25:32

If one doesn't care about the year/month/date, the upper values can be removed via modulus first

phantombrain 2010-03-01 08:42:27

Answer 2

+3 A:

This is the code behind TimeUnit.MILLISECONDS.toSecond(long d):

public long toSeconds(long d) { return d/(C3/C2); }

where C2,C3 are static constants. You can save a single division... In that case, I preferred your actual code, it's easier to understand

Andreas_D 2010-03-01 08:38:31

If C2 and C3 are constants, the _compiler_ calculates the result of C3/C2 and uses that.

Thorbjørn Ravn Andersen 2010-03-01 10:43:42

Even better ;) Then it's *as fast as possible*

Andreas_D 2010-03-01 11:42:41

Answer 3

+1 A:

Assuming t1 and t2 are time stamps. Eg from System.currentTimeMillis()

public static boolean isSameSecond(long t1, long t2){
  return (t1/1000) == (t2/1000)
}

Paul 2010-03-01 09:02:24

What's the most efficient way to check whether two long values (in millis) belong to the same second