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Groups > comp.lang.java.programmer > #39129
| From | Eric Sosman <esosman@comcast-dot-net.invalid> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Best way to make a hashcode? |
| Date | 2019-08-27 15:16 -0400 |
| Organization | A noiseless patient Spider |
| Message-ID | <qk3vi4$6f9$1@dont-email.me> (permalink) |
| References | (2 earlier) <11fd675f-2de2-49a1-baee-b77c2c8d8775@googlegroups.com> <qk3bq2$fh9$1@dont-email.me> <cbde76cd-4227-4f2c-b33f-54d8c3edebeb@googlegroups.com> <qk3jf9$s8n$1@dont-email.me> <07eb0e1e-eaa8-4a84-bf1f-f27c10277395@googlegroups.com> |
On 8/27/2019 2:05 PM, Eric Douglas wrote:
> [...]
> So, if I make a custom class that holds the values I need to generate one of their objects, and I don't need to be so super dynamic and super generic, the hard-coded hashcode as generated by the IDE is much more efficient..(just not interchangeable as to be created by one version of the class and compared to another should there be any changes that affect the hashcode)
It looks like direct hash computation should beat the pants off
render-as-string-and-hash-the-string, almost certainly and almost
always. (Suggested experiment, if you're interested: Compute a few
thousand hashes each way to warm up, then compute a few thousand
more and note the elapsed time. Additional fillip: Use the methods
of Runtime to approximate the memory used before and after -- but
realize this will only give an approximation.)
Interchangeability of hash values is probably not a concern.
It is not unheard-of for instances of different classes to equals()
each other, but it is fairly unusual.
--
esosman@comcast-dot-net.invalid
Five hundred twelve days to go.
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Best way to make a hashcode? Eric Douglas <e.d.programmer@gmail.com> - 2019-08-26 13:51 -0700
Re: Best way to make a hashcode? Eric Sosman <esosman@comcast-dot-net.invalid> - 2019-08-26 17:41 -0400
Re: Best way to make a hashcode? Eric Douglas <e.d.programmer@gmail.com> - 2019-08-27 06:24 -0700
Re: Best way to make a hashcode? Eric Sosman <esosman@comcast-dot-net.invalid> - 2019-08-27 09:39 -0400
Re: Best way to make a hashcode? Eric Douglas <e.d.programmer@gmail.com> - 2019-08-27 07:29 -0700
Re: Best way to make a hashcode? Eric Sosman <esosman@comcast-dot-net.invalid> - 2019-08-27 11:49 -0400
Re: Best way to make a hashcode? Eric Douglas <e.d.programmer@gmail.com> - 2019-08-27 11:05 -0700
Re: Best way to make a hashcode? Eric Sosman <esosman@comcast-dot-net.invalid> - 2019-08-27 15:16 -0400
Re: Best way to make a hashcode? Eric Douglas <e.d.programmer@gmail.com> - 2019-08-27 13:04 -0700
Re: Best way to make a hashcode? Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2019-08-27 23:51 +0200
Re: Best way to make a hashcode? Silvio <silvio@internet.com> - 2019-08-28 01:27 +0200
Re: Best way to make a hashcode? Marcel Mueller <news.5.maazl@spamgourmet.org> - 2019-09-06 19:42 +0200
Re: Best way to make a hashcode? Arne Vajhøj <arne@vajhoej.dk> - 2019-08-26 19:03 -0400
Re: Best way to make a hashcode? Eric Douglas <e.d.programmer@gmail.com> - 2019-08-27 04:59 -0700
Re: Best way to make a hashcode? Arne Vajhøj <arne@vajhoej.dk> - 2019-08-27 21:08 -0400
Re: Best way to make a hashcode? ross.finlayson@gmail.com - 2019-09-05 20:27 -0700
Re: Best way to make a hashcode? trisha guillot <guillottrisha347@gmail.com> - 2020-01-18 07:25 -0800
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