Thanks Sampo looks good, and yeah if we catch other code doing String
intern() it is good to hunt it down (should of been caught during initial
review).
Jody Garnett
On Wed, Nov 19, 2014 at 12:07 AM, Sampo Savolainen <
[email protected]> wrote:
> Hi,
>
> I've now protected the code with a ReadWriteLock:
> https://github.com/sampov2/geotools/commit/c3b41de9217a6b14d15700f3a2d07de88480c4ce
>
> The String intern() pattern was actually a common pattern used in other
> places in WFSDataStore. If you accept my implementation, it would make
> sense to use the pattern in the other methods as well.
>
>
> Sampo
>
> On Thu, Nov 13, 2014 at 4:02 PM, Jody Garnett <[email protected]>
> wrote:
>
>> We tend to use the java concurrency API, for an example a ReadWrite lock
>> if that is appropriate.
>>
>> Jody Garnett
>>
>> On Mon, Nov 10, 2014 at 11:26 PM, Sampo Savolainen <
>> [email protected]> wrote:
>>
>>> Hi,
>>>
>>> Last spring I worked on creating Cascaded WFS 2.0.0 Stored Query support
>>> into GeoTools and GeoServer. This work has been done for the Finnish
>>> Meteorological Institute. I've now resumed my work after GeoServer 2.6 got
>>> released and development stabilized (and my schedule freed up), and I'm
>>> working on a pull request for GeoTools. I've been discussing the changes
>>> with Jody and I and/or we have two questions for all of you regarding our
>>> conversation. I've split these two questions into separate emails so the
>>> discussion won't get confused.
>>>
>>> Also, if anyone else wants to check out the pull request, please do.
>>> Given enough eyeballs, and so on.
>>>
>>>
>>> In wfs-ng WFSDataStore, I have a Map for caching
>>> StoredQueryDescriptions. The key for the map is the id of the stored query
>>> in question (as a String). The Map is populated lazily and it's entirely
>>> possible that multiple threads might access the same stored query at the
>>> same time. I use a ConcurrentHashMap to avoid basic synchronization issues,
>>> but this particular code is to safeguard GeoTools from querying the same
>>> information from the WFS in multiple threads at the same time.
>>>
>>>
>>> https://github.com/sampov2/geotools/commit/f8a7d7cfe9c3c75e5619d9960a6747a220af1e43#commitcomment-8379257
>>>
>>> The current strategy is very naive (synchronized(id.intern()) { }) and
>>> as Jody correctly points out, other bits of code might be synchronizing on
>>> these interned Strings.
>>>
>>> My question is if there is a preferred and often used locking strategy
>>> in GeoTools that fits the bill here?
>>>
>>>
>>> Thanks,
>>> Sampo
>>>
>>> --
>>> Sampo Savolainen
>>> R&D Director, Spatineo Oy
>>> [email protected]
>>> +358-407555649
>>> Linnankoskenkatu 16 A 17, 00250 Helsinki, Finland
>>> www.spatineo.com, twitter.com/#!/spatineo
>>> www.linkedin.com/company/spatineo-inc
>>>
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>>
>
>
> --
> Sampo Savolainen
> R&D Director, Spatineo Oy
> [email protected]
> +358-407555649
> Linnankoskenkatu 16 A 17, 00250 Helsinki, Finland
> www.spatineo.com, twitter.com/#!/spatineo
> www.linkedin.com/company/spatineo-inc
>
> This message may contain privileged and/or confidential information. If you
> have received this e-mail in error or are not the intended recipient, you
> may not use, copy, disseminate, or distribute it; do not open any
> attachments, delete it immediately from your system and notify the sender
> promptly by e-mail that you have done so.
>
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