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Posted to java-user@lucene.apache.org by aravinth thangasami <ar...@gmail.com> on 2016/08/04 06:22:37 UTC
Why we need org.apache.lucene.codecs.Codec
Hi all,
Re: Why we need org.apache.lucene.codecs.Codec
Posted by Greg Bowyer <gb...@fastmail.co.uk>.
Not quite sure what you mean, lucene needs some way to load a codec, and
give parts of an index written with different codecs it would need
tonload and select the right code at the right time.
Consider, for example the upgrade path. Let's say you have segments
written with code 5.x and we in place upgrade to 6.x, lucene is going to
need to know how to load up the codec for 5.x and 6.x.
On Thu, Aug 4, 2016, at 09:03 AM, Aravinth T wrote:
> I understand that, my question is different why we are loading it with
> SPI,
>
> why we explicitly controlling the loading of Codecs
>
>
>
>
> ---- On Thu, 04 Aug 2016 20:39:46 +0530 Greg Bowyer
> <gbowyer@fastmail.co.uk>wrote ----
>
>
>
>
> Codecs are loaded with the java service loader interface. That file is
>
> the hook used to tell the service loader that this jar implements Codec.
>
>
>
> Lucene internally calls service loader and asks what codecs are there.
>
>
>
> On Wed, Aug 3, 2016, at 11:23 PM, aravinth thangasami wrote:
>
> > I don't understand why we need to add custom codec name in this file
>
> >
>
> > Thanks & Regards
>
> > Aravinth
>
> >
>
> > On Thu, Aug 4, 2016 at 11:52 AM, aravinth thangasami <
>
> > aravinththangasami@gmail.com> wrote:
>
> >
>
> > > Hi all,
>
> > >
>
> > >
>
>
>
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Re: Why we need org.apache.lucene.codecs.Codec
Posted by Aravinth T <ar...@zohocorp.com>.
I understand that, my question is different why we are loading it with SPI,
why we explicitly controlling the loading of Codecs
---- On Thu, 04 Aug 2016 20:39:46 +0530 Greg Bowyer <gbowyer@fastmail.co.uk>wrote ----
Codecs are loaded with the java service loader interface. That file is
the hook used to tell the service loader that this jar implements Codec.
Lucene internally calls service loader and asks what codecs are there.
On Wed, Aug 3, 2016, at 11:23 PM, aravinth thangasami wrote:
> I don't understand why we need to add custom codec name in this file
>
> Thanks & Regards
> Aravinth
>
> On Thu, Aug 4, 2016 at 11:52 AM, aravinth thangasami <
> aravinththangasami@gmail.com> wrote:
>
> > Hi all,
> >
> >
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Re: Why we need org.apache.lucene.codecs.Codec
Posted by Uwe Schindler <uw...@thetaphi.de>.
Hi,
The Codec class is the abstract base class for all index codecs. The implementation is loaded via SPI from classpath. To understand how this works read API doc's of Java ServiceLoader which describes the process.
Uwe
Am 4. August 2016 17:09:46 MESZ, schrieb Greg Bowyer <gb...@fastmail.co.uk>:
>Codecs are loaded with the java service loader interface. That file is
>the hook used to tell the service loader that this jar implements
>Codec.
>
>Lucene internally calls service loader and asks what codecs are there.
>
>On Wed, Aug 3, 2016, at 11:23 PM, aravinth thangasami wrote:
>> I don't understand why we need to add custom codec name in this file
>>
>> Thanks & Regards
>> Aravinth
>>
>> On Thu, Aug 4, 2016 at 11:52 AM, aravinth thangasami <
>> aravinththangasami@gmail.com> wrote:
>>
>> > Hi all,
>> >
>> >
>
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--
Uwe Schindler
H.-H.-Meier-Allee 63, 28213 Bremen
http://www.thetaphi.de
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Re: Why we need org.apache.lucene.codecs.Codec
Posted by Greg Bowyer <gb...@fastmail.co.uk>.
Codecs are loaded with the java service loader interface. That file is
the hook used to tell the service loader that this jar implements Codec.
Lucene internally calls service loader and asks what codecs are there.
On Wed, Aug 3, 2016, at 11:23 PM, aravinth thangasami wrote:
> I don't understand why we need to add custom codec name in this file
>
> Thanks & Regards
> Aravinth
>
> On Thu, Aug 4, 2016 at 11:52 AM, aravinth thangasami <
> aravinththangasami@gmail.com> wrote:
>
> > Hi all,
> >
> >
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Re: Why we need org.apache.lucene.codecs.Codec
Posted by aravinth thangasami <ar...@gmail.com>.
I don't understand why we need to add custom codec name in this file
Thanks & Regards
Aravinth
On Thu, Aug 4, 2016 at 11:52 AM, aravinth thangasami <
aravinththangasami@gmail.com> wrote:
> Hi all,
>
>