Marc Dzaebel schreef:

You could always use a LongComparator implements Comparator<Long, Long>
to avoid the new Long()

Do you rely on the result of compareTo being -1 or +1?  You shouldn’t!
If not, then why even write a function and not just use l1-l2?

Same goes for ints.  For bytes, shorts and chars the situation is
different, because of auto-conversion.  But then again, compareTo gives
you an int too, so this is exactly what you want.

Only for floating point numbers would you have to watch out, because
float1-float2 is not always 0, even when they have the ‘same’ value (or
the inverse).

H.
- --
Hendrik Maryns

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There are only a few cases when you need an explicit method to compare
numbers. Typically simple if() statements are OK:

    if(l1 > l2) {

    } else if(l1 < l2) {

    } else {

    }

Which is anyhow simpler than:

    int c = MyUtility.compareTo(l1, l2);
    if(c > 0) {

    } else if(c < 0) {

    } else {

    }

or

    int c = new Long(l1).compareTo(l2);
    if(c > 0) {

    } else if(c < 0) {

    } else {

    }

You only need to explicitly call compareTo() methods in Java if you need
to determine some order between instances of a class, but if your code
has no knowledge about that order. This is typically not the case if you
know you are dealing with longs.

It is e.g. the case for universal/reusable sort routines which are
supposed to be capable of sorting "everything". Such routines are
typically written to handle only objects, not to handle primitive types
- to avoid having to duplicate code. So using such routines typically
has to result in boxing/unboxing when you want to use them with
primitives. But that boxing happens because of the particular sorting
routine's implementation. Methods like Long.compareTo() simply exist to
support such routines. They are not intended for general usage.

    public static long compareTo(long l1, long l2) {
        return l1 - l2;
    }

Design of what? What is it what you actually want to change? class Long?

/Thomas

I think it's just that there isn't a lot of need for such a method, and it's
easy enough to create your own.  Maybe it'll be added someday.

   -- chris