This sort of stuff is why I scream "NNNNOOOOOOOOOOOOOO!!!!!!" when people store date/time as integers (i.e. "unix timestamps") when almost every database and programming language has a proper date or datetime data type, and a boatload of library functions that correctly compute differences between dates, handle leap years and time zones, etc. Well maybe not always correctly, but it's more likely that YOU will screw u…
At least in Java, storing a date/time as a primitive improves immutability and is a good pattern.
You don't expose the underlying long value publicly so you end up with something like the following:
private long primitiveDate;
public Date getDate() { return new Date(primitiveDate); }
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This prevents calling methods from doing something stupid like:
o.getDate().setTime(123455L)
to modify a date that shouldn't be editable.