Re: inverse sort on key?

Knute Johnson <>
Tue, 05 Aug 2008 13:52:46 -0700
<4898bd9e$0$4016$> wrote:

I have an object (say, Car). Car contains some values, one of which
is speed. I want to store lots of cars in some sort of object that
will keep them sorted by speed. Some cars may have the same speed.
The catch is that I want to sort by highest speed, not lowest speed.
If I insert lots of cars into a TreeSet, with the key being the speed,
I get them in increasing order. If there are n cars with the same
speed, I get only one, because the keys are identical. I've been
unable to find an object that would work. I've tried implementing a
compare method in my object, and that doesn't help either. Any ideas?

To summarize, the container object must:
1) Support sorting in inverse order (or another order of my choice)
2) Keep the objects sorted.
3) Support duplicate objects.

(I suppose I could sort on the negative value of the sort key, but...)


You can keep the objects in a sorted array using a comparator to sort on
whatever field you want. Duplicate objects implies duplicate keys which
I don't think is possible with Maps or Sets so some sort of array you
keeps sorted is probably your best bet.


Knute Johnson
email s/nospam/knute2008/

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