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Groups > comp.lang.java.programmer > #30976
| From | Knute Johnson <eternal@knutejohnson.com> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Concurrency question? |
| Date | 2015-01-31 19:51 -0800 |
| Organization | A noiseless patient Spider |
| Message-ID | <mak7rp$d2e$1@dont-email.me> (permalink) |
| References | <maj766$qjf$1@dont-email.me> <maj9tb$l45$3@Gaia.teknon.de> <majen2$psi$1@dont-email.me> |
On 01/31/2015 12:42 PM, Eric Sosman wrote: > On 1/31/2015 2:20 PM, Volker Borchert wrote: >> Knute Johnson wrote: >>> So I have a Map<Integer,String> [ ... ] >>> >>> Do you see any holes in my logic? Any suggestions? >> >> java.util.concurrent.ConcurrentHashMap<K,V> > > That's fine if the consistency criterion involves only single > mappings. But if different mappings within the same Map must "agree" > (in some application-dependent sense), atomicity of individual updates > isn't good enough. > > Only Knute knows for sure ... > When I first saw Volker's suggestion I thought, no I can't iterate over the map without some other synchronization but I looked into the ConcurrentHashMap docs and found; "Similarly, Iterators, Spliterators and Enumerations return elements reflecting the state of the hash table at some point at or since the creation of the iterator/enumeration. They do not throw ConcurrentModificationException. However, iterators are designed to be used by only one thread at a time." As subtle as his suggestion was, I think he may be on to something. I'm going to think about it some more but Volker may have the simplest solution. -- Knute Johnson
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Concurrency question? Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2015-01-31 10:34 -0800
Re: Concurrency question? Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-01-31 14:04 -0500
Re: Concurrency question? Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2015-01-31 11:23 -0800
Re: Concurrency question? Arne Vajhøj <arne@vajhoej.dk> - 2015-01-31 14:12 -0500
Re: Concurrency question? Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2015-01-31 11:33 -0800
Re: Concurrency question? v_borchert@despammed.com (Volker Borchert) - 2015-01-31 19:20 +0000
Re: Concurrency question? Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-01-31 15:42 -0500
Re: Concurrency question? Knute Johnson <eternal@knutejohnson.com> - 2015-01-31 19:51 -0800
Re: Concurrency question? Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-02-01 09:24 -0500
Re: Concurrency question? Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2015-01-31 22:59 -0800
Re: Concurrency question? Arne Vajhøj <arne@vajhoej.dk> - 2015-02-01 12:55 -0500
Re: Concurrency question? Silvio <silvio@internet.com> - 2015-02-01 22:19 +0100
Re: Concurrency question? Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2015-02-06 22:29 -0800
Re: Concurrency question? Knute Johnson <eternal@knutejohnson.com> - 2015-02-07 10:14 -0800
Re: Concurrency question? Robert Klemme <shortcutter@googlemail.com> - 2015-02-08 19:33 +0100
Re: Concurrency question? olupot douglas <olupotd3@gmail.com> - 2015-02-07 01:06 -0800
Re: Concurrency question? Haddock <ffm2002@web.de> - 2015-02-16 06:32 -0800
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