Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.java.programmer > #37069
| From | Eric Sosman <esosman@comcast-dot-net.invalid> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: What's the best way to make a cross string set? |
| Date | 2017-08-05 17:25 -0400 |
| Organization | A noiseless patient Spider |
| Message-ID | <om5ct1$g6d$1@dont-email.me> (permalink) |
| References | (14 earlier) <fa610c79-f1b6-43b6-85fa-ffc4ca5298d4@googlegroups.com> <olvn2h$9kv$1@dont-email.me> <abafc97c-13c8-4934-9f55-0e0606c126c7@googlegroups.com> <om58cc$2bd$1@dont-email.me> <om59v8$41u$1@dont-email.me> |
On 8/5/2017 4:31 PM, Martin Gregorie wrote:
> On Sat, 05 Aug 2017 16:08:36 -0400, Eric Sosman wrote:
>
>> Upon reflection, strike "in a sensible way" and replace with
>> "at all, without violating the contract of Comparable." The problem is
>> that Comparable must implement a /total order/, which means (among other
>> things) that it must be asymmetric: The sign of x.compareTo(y) must be
>> opposite that of y.compareTo(x), or both must be zero. Now, you may
>> contrive a class that claims to implement Comparable<Object> and endow
>> it with a compareTo() method that does, in fact, accept any kind of
>> Object and return some kind of result
>>
> There are other implications that seem to me to make this an absolute
> requirement. Eric's switchable comparison would have severe side effects
> on other classes, e.g. changing his style switch setting should logically
> force a SortedMap to automatically reorder itself.
It turns out that he's not trying to change the ordering
rule in mid-stream (at least, he didn't show any such attempt).
Rather, he's got an obfuscated way of implementing a two-part
key: The first part is this "style" number, and if the numbers
agree the second is either a String or an int (disguised as an
Integer), depending on the style.
True, if he were to change the style of an object already
in a SortedSomething then the fertilizer would hit the fan.
But that's just a particular case of the general caution against
mutating an object that's in a Set or Map or other value-sensitive
data structure.
--
esosman@comcast-dot-net.invalid
Twelve hundred sixty-four days to go.
Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-27 12:12 -0700
Re: What's the best way to make a cross string set? Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2017-07-27 14:38 -0500
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-27 12:49 -0700
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-07-27 15:49 -0400
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-27 12:55 -0700
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-27 13:22 -0700
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-27 13:30 -0700
Re: What's the best way to make a cross string set? Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2017-07-27 15:34 -0500
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-07-27 18:27 -0400
Re: What's the best way to make a cross string set? lewbloch@gmail.com - 2017-07-28 18:51 -0700
Re: What's the best way to make a cross string set? v_borchert@despammed.com (Volker Borchert) - 2017-07-29 06:03 +0000
Re: What's the best way to make a cross string set? v_borchert@despammed.com (Volker Borchert) - 2017-07-28 18:19 +0000
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-28 13:28 -0700
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-07-28 17:20 -0400
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-31 05:24 -0700
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-07-31 12:01 -0400
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-07-31 10:58 -0700
Re: What's the best way to make a cross string set? Sebastian <nowhere@nirvana.org> - 2017-07-31 18:13 +0200
Re: What's the best way to make a cross string set? lewbloch@gmail.com - 2017-07-31 09:24 -0700
Re: What's the best way to make a cross string set? Arne Vajhøj <arne@vajhoej.dk> - 2017-07-31 19:24 -0400
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-08-01 06:36 -0700
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-08-01 10:58 -0400
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-08-01 08:09 -0700
Re: What's the best way to make a cross string set? lewbloch@gmail.com - 2017-08-01 09:39 -0700
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-08-01 10:18 -0700
Re: What's the best way to make a cross string set? Andreas Leitgeb <avl@logic.at> - 2017-08-02 09:22 +0000
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-08-02 05:13 -0700
Re: What's the best way to make a cross string set? Andreas Leitgeb <avl@logic.at> - 2017-08-03 14:33 +0000
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-08-03 08:51 -0700
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-08-03 12:20 -0400
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-08-03 10:15 -0700
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-08-03 13:42 -0400
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-08-03 11:17 -0700
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-08-05 16:08 -0400
Re: What's the best way to make a cross string set? Martin Gregorie <martin@address-in-sig.invalid> - 2017-08-05 20:31 +0000
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-08-05 17:25 -0400
Re: What's the best way to make a cross string set? Martin Gregorie <martin@address-in-sig.invalid> - 2017-08-05 22:11 +0000
Re: What's the best way to make a cross string set? Sebastian <nowhere@nirvana.org> - 2017-08-06 18:13 +0200
Re: What's the best way to make a cross string set? Eric Douglas <e.d.programmer@gmail.com> - 2017-08-02 12:56 -0700
Re: What's the best way to make a cross string set? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-07-29 16:55 -0400
Re: What's the best way to make a cross string set? Sebastian <nowhere@nirvana.org> - 2017-07-29 23:56 +0200
csiph-web