Re: Comparable loses its interface powers.
Thomas Pornin <pornin@bolet.org> wrote, quoted or indirectly quoted someone
who said :
In your situation, you have to
"know" which instances of Comparable can be compared to each other and
which cannot.
Roedy Green wrote:
In the old days, so long as each column contained compatible things,
you could just use Comparable.compareTo and all would automagically
sort itself out. Today you get squawking if you do it because, for
example, String no longer implements Comparable, it implements
Comparable<String> which will not cast to Comparable or
Comparable<Object>
markspace wrote:
I'm pretty sure String will cast to Comparable<String>.
Of course it will. I don't know where the notion comes from that 'String'
does not implement 'Comparable<String>', when it says right in the Javadocs
that it does.
And the requirement that generics impose that you specify what ensures that a
column "contained compatible things" is the key. Roedy waves a magic wand
with that offhand phrase, but the whole point of generics is to make that a
compile-time check, instead of a run-time check in "the old days". "All" did
not "automagically sort itself out" because if you violated that "so long as"
condition via a bug or other means, you'd get a weird results. I mean, what
if you put an Float and a Double, say, into the same column in "the old days"?
What would happen?
With generics you'd know that at compile time and avoid an expensive,
embarrassing bug. That's the thing that makes the "new days" so much better.
--
Lew