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| From | Robert Klemme <shortcutter@googlemail.com> |
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Alternative to TreeSet? |
| Date | Tue, 07 May 2013 07:58:34 +0200 |
| Lines | 33 |
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On 06.05.2013 17:25, Daniel Pitts wrote: > On 5/6/13 8:10 AM, laredotornado@zipmail.com wrote: >> We're using Java 6. Is there a java.util.Set data structure that can >> return a sorted list of elements and can contain two elements even if >> compareTo returns 0 against those two elements but calling equals >> against the two elements returns false? TreeSet doesn't do the job. >> >> In our example, we have products with an order ID column, so two >> products could have the same order ID but may not be equal. We would >> like to sort the products based on this order ID, however. > It sounds like you don't want a set, but a sorted bag. There may be > something in Apache Commons to solve this problem for you. Depending on > the size of the data set, I'd probably just use an ArrayList and call > Collections.sort(). And there are methods for binary search which will help with finding element positions efficiently, e.g. http://docs.oracle.com/javase/6/docs/api/java/util/Arrays.html#binarySearch(java.lang.Object[], int, int, java.lang.Object) I am not entirely sure though whether OP really wants a multiset (bag) or just a custom ordering which takes more fields into account. It depends on the operations executed on the collection. Kind regards robert -- remember.guy do |as, often| as.you_can - without end http://blog.rubybestpractices.com/
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Alternative to TreeSet? laredotornado@zipmail.com - 2013-05-06 08:10 -0700
Re: Alternative to TreeSet? Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-05-06 11:19 -0400
Re: Alternative to TreeSet? Lew <lewbloch@gmail.com> - 2013-05-06 11:33 -0700
Re: Alternative to TreeSet? Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-05-06 18:01 -0300
Re: Alternative to TreeSet? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-05-06 08:25 -0700
Re: Alternative to TreeSet? Robert Klemme <shortcutter@googlemail.com> - 2013-05-07 07:58 +0200
Re: Alternative to TreeSet? Roedy Green <see_website@mindprod.com.invalid> - 2013-05-07 09:21 -0700
Re: Alternative to TreeSet? Sven Köhler <remove-sven.koehler@gmail.com> - 2013-05-07 19:36 +0300
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