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Groups > comp.lang.java.programmer > #9817

Re: equals(), Sets, Maps, and degrees of equality

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Owen Jacobson wrote:
> > 	[ class to be used in multiple Maps with different equalities ]
> > 
> > I suppose I could create a wrapper class for each purpose which only 
> > overrides equals() and hashcode(), but that seems very unsatisfying and 
> > inefficient.
> 
> That's one option, and it's not as inefficient (at least in terms of 
> run time) as you might expect, unless you have several million wrappers 
> kicking around. It's clunky to write, true.
> 
> Another option is the TreeSet and TreeMap classes, which have slightly 
> worse lookup and insertion complexity guarantees (amortized O(log n) vs 
> amortized O(1) on lookup, for example) but allow passing a Comparator 
> that also controls equality tests for that set or map.

Yet another option is to write your own HashMap.

-- 

"I'm a doctor, not a mechanic." Dr Leonard McCoy <mccoy@ncc1701.starfleet.fed>
"I'm a mechanic, not a doctor." Volker Borchert  <v_borchert@despammed.com>

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equals(), Sets, Maps, and degrees of equality Sean Mitchell <sean@mitchwood.com> - 2011-11-09 18:33 -0800
  Re: equals(), Sets, Maps, and degrees of equality Owen Jacobson <angrybaldguy@gmail.com> - 2011-11-09 22:10 -0500
    Re: equals(), Sets, Maps, and degrees of equality v_borchert@despammed.com (Volker Borchert) - 2011-11-10 04:42 +0000
  Re: equals(), Sets, Maps, and degrees of equality Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-09 22:11 -0500
    Re: equals(), Sets, Maps, and degrees of equality markspace <-@.> - 2011-11-09 22:43 -0800
      Re: equals(), Sets, Maps, and degrees of equality Sean Mitchell <sean@mitchwood.com> - 2011-11-10 06:33 -0800
        Re: equals(), Sets, Maps, and degrees of equality markspace <-@.> - 2011-11-10 07:21 -0800
          Re: equals(), Sets, Maps, and degrees of equality Sean Mitchell <sean@mitchwood.com> - 2011-11-10 07:29 -0800
            Re: equals(), Sets, Maps, and degrees of equality markspace <-@.> - 2011-11-10 10:27 -0800
            Re: equals(), Sets, Maps, and degrees of equality Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-10 20:58 -0500
              Re: equals(), Sets, Maps, and degrees of equality markspace <-@.> - 2011-11-10 19:07 -0800
                Re: equals(), Sets, Maps, and degrees of equality Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-10 23:24 -0500
                Re: equals(), Sets, Maps, and degrees of equality markspace <-@.> - 2011-11-10 20:55 -0800
              Re: equals(), Sets, Maps, and degrees of equality Sean Mitchell <sean@mitchwood.com> - 2011-11-11 10:27 -0800
                Re: equals(), Sets, Maps, and degrees of equality Lew <lewbloch@gmail.com> - 2011-11-11 14:21 -0800
    Re: equals(), Sets, Maps, and degrees of equality Sean Mitchell <sean@mitchwood.com> - 2011-11-10 06:31 -0800
      Re: equals(), Sets, Maps, and degrees of equality Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-10 11:27 -0800
  Re: equals(), Sets, Maps, and degrees of equality Roedy Green <see_website@mindprod.com.invalid> - 2011-11-10 16:01 -0800
  Re: equals(), Sets, Maps, and degrees of equality Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-11-11 09:08 +0000
    Re: equals(), Sets, Maps, and degrees of equality Lew <lewbloch@gmail.com> - 2011-11-11 07:27 -0800
      Re: equals(), Sets, Maps, and degrees of equality Sean Mitchell <sean@mitchwood.com> - 2011-11-11 10:28 -0800
        Re: equals(), Sets, Maps, and degrees of equality Lew <lewbloch@gmail.com> - 2011-11-11 14:22 -0800
          Re: equals(), Sets, Maps, and degrees of equality markspace <-@.> - 2011-11-11 15:19 -0800
          Re: equals(), Sets, Maps, and degrees of equality Lew <lewbloch@gmail.com> - 2011-11-13 21:18 -0800
            Re: equals(), Sets, Maps, and degrees of equality Lew <lewbloch@gmail.com> - 2011-11-16 09:15 -0800

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