CODEWITHSUNDEEP
javaunix-timestamp
Roshan
Roshan

Reputation: 2059

How to validate the unix timestamp in java?

I need validate the given input String is a valid Timestamp in milliseconds.

For example if the given Timestamp

String time ="1310966356458";

Then it should return true.

if 

String time ="1000";

then it should return false;

Please help. Thanks in advance

Upvotes: 3

Views: 17254

Answers (3)

maryf
maryf

Reputation: 150

Very old question but here is how I did it:

   boolean isNumberValue(String value) {
      //TODO - check if is number
      String regex = "^[0-9]+$";
      Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
      Matcher matcher = pattern.matcher(value);
      boolean matchFound = matcher.find();

      if(matchFound) {
           //System.out.println("Match found");
           return true;
      } else {
          //System.out.println("Match not found");
          return false;
      }
   }

   boolean isTimestamp(String timestamp) {      
        try {
            long time = Long.valueOf(timestamp);
            Date date = new Date((long)time);
            long dateOld = date.getTime();
            //if no exception was raised, then its unix and only digits
            if(!isNumberValue(String.valueOf(dateOld))) {
                return false;
            }
            return true;
        } catch (Exception e) {
            return false;
        }
      
   }

   if (isTimestamp(1679308838)){
       System.out.println("Is unix timestamp");
   }else{
       System.out.println("NOT unix timestamp");
   }

Upvotes: 0

Peter Lawrey
Peter Lawrey

Reputation: 533880

We cannot tell you what is sensible for your application. If there was a limit which was correct for every situation it would be built in. It could be that only timestamps after you developed your application and not in the future are sensible.

public static final String RELEASE_DATE = "2011/06/17";
private static final long MIN_TIMESTAMP;

static {
    try {
        MIN_TIMESTAMP = new SimpleDateFormat("yyyy/MM/dd").parse(RELEASE_DATE).getTime();
    } catch (ParseException e) {
        throw new AssertionError(e);
    }
}

// after the software was release and not in the future.
public static final boolean validTimestamp(long ts) {
    return ts >= MIN_TIMESTAMP && ts <= System.currentTimeMillis();
}

However, it could be that the timestamp represents when someone was born. In which case the minimum timestamp could be negative.

It could be that the timestamp is the time when something expires (like tickets) Some will be in the past (perhaps not before this year) and some will be in the future. (perhaps not more than 2 years in advance.)

Times can be negative. Man landed on the moon before 1970 so the timestamp would be negative.

String MAN_ON_MOON = "1969/07/21 02:56 GMT";
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm Z");
System.out.println(sdf.parse(MAN_ON_MOON).getTime());

prints

-14159040000

Upvotes: 14

Joel
Joel

Reputation: 126

Why not just subtract the epoch time from the time you're given. If the result is negative, then it's not valid.

Upvotes: 0

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