Background
The Netcool OMNIbus ObjectServer expects timestamp values to be the number of seconds since epoch (00:00:00 UTC on 1 January 1970). This is a 10-digit number. However, some systems generate a timestamp that is the number of milliseconds since epoch (a 13-digit number). This causes the timestamp to be interpreted wildly incorrectly in the ObjectServer. One such event source is Nokia NSP, which integrates with Netcool via the Probe for Message Bus.
Conversion Process
My process of converting the 13-digit timestamp to the correct 10-digit one is straightforward:
# convert timestamp to string by concatenating it with a string
$millString = $timestampInMilliseconds + ""
# take the first 10 characters
$secondsString = substr($millString,1,10)
# convert back to an integer
$validTimestamp = int($secondsString)
# store in FirstOccurrence of Event
@FirstOccurrence = $validTimestamp
That's it.