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https://issues.apache.org/jira/browse/SOLR-3056?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13203662#comment-13203662
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Christian Moen commented on SOLR-3056:
--------------------------------------

Thanks, Robert.

I was thinking to leave the {{StopFilter}} case-sensitive as I thought not 
having it normalized would give us flexibility, but it's also prone to error 
and surprises.  I think it's reasonable to do make the default ignore case to 
support adding English or other romaji terms to the stopset with ease.

However, if we following down this path path, we might also want to do 
width-normalization for the Japanese stopset to make sure there's no confusion 
with that, either.  I suggest that we resolve that as a separate issue.

I think it's still reasonable to leave the {{LowerCaseFilter}} last as-is, 
though, so that users won't need to reorder the chain in case they want 
case-sensitive stopping.

I'll update the configuration in both {{KuromojiAnalyzer}} and the {{text_ja}} 
field type to ignore case in their {{StopFilter}} tomorrow.
                
> Introduce Japanese field type in schema.xml
> -------------------------------------------
>
>                 Key: SOLR-3056
>                 URL: https://issues.apache.org/jira/browse/SOLR-3056
>             Project: Solr
>          Issue Type: New Feature
>          Components: Schema and Analysis
>    Affects Versions: 3.6, 4.0
>            Reporter: Christian Moen
>         Attachments: SOLR-3056.patch, SOLR-3056_move.patch, 
> SOLR-3056_schema40.patch, SOLR-3056_schema40.patch, SOLR-3056_schema40.patch
>
>
> Kuromoji (LUCENE-3305) is now on both on trunk and branch_3x (thanks again 
> Robert, Uwe and Simon). It would be very good to get a default field type 
> defined for Japanese in {{schema.xml}} so we can good Japanese out-of-the-box 
> support in Solr.
> I've been playing with the below configuration today, which I think is a 
> reasonable starting point for Japanese.  There's lot to be said about various 
> considerations necessary when searching Japanese, but perhaps a wiki page is 
> more suitable to cover the wider topic?
> In order to make the below {{text_ja}} field type work, Kuromoji itself and 
> its analyzers need to be seen by the Solr classloader.  However, these are 
> currently in contrib and I'm wondering if we should consider moving them to 
> core to make them directly available.  If there are concerns with additional 
> memory usage, etc. for non-Japanese users, we can make sure resources are 
> loaded lazily and only when needed in factory-land.
> Any thoughts?
> {code:xml}
> <!-- Text field type is suitable for Japanese text using morphological 
> analysis
>      NOTE: Please copy files
>        contrib/analysis-extras/lucene-libs/lucene-kuromoji-x.y.z.jar
>        dist/apache-solr-analysis-extras-x.y.z.jar
>      to your Solr lib directory (i.e. example/solr/lib) before before 
> starting Solr.
>      (x.y.z refers to a version number)
>      If you would like to optimize for precision, default operator AND with
>        <solrQueryParser defaultOperator="AND"/>
>      below (this file).  Use "OR" if you would like to optimize for recall 
> (default).
> -->
> <fieldType name="text_ja" class="solr.TextField" positionIncrementGap="100" 
> autoGeneratePhraseQueries="false">
>   <analyzer>
>     <!-- Kuromoji Japanese morphological analyzer/tokenizer
>          Use search-mode to get a noun-decompounding effect useful for search.
>          Example:
>            関西国際空港 (Kansai International Airpart) becomes 関西 (Kansai) 国際 
> (International) 空港 (airport)
>            so we get a match for 空港 (airport) as we would expect from a good 
> search engine
>          Valid values for mode are:
>             normal: default segmentation
>             search: segmentation useful for search (extra compound splitting)
>           extended: search mode with unigramming of unknown words 
> (experimental)
>          NOTE: Search mode improves segmentation for search at the expense of 
> part-of-speech accuracy
>     -->
>     <tokenizer class="solr.KuromojiTokenizerFactory" mode="search"/>
>     <!-- Reduces inflected verbs and adjectives to their base/dectionary 
> forms (辞書形) -->      
>     <filter class="solr.KuromojiBaseFormFilterFactory"/>
>     <!-- Optionally remove tokens with certain part-of-speeches
>     <filter class="solr.KuromojiPartOfSpeechStopFilterFactory" 
> tags="stopTags.txt" enablePositionIncrements="true"/> -->
>     <!-- Normalizes full-width romaji to half-with and half-width kana to 
> full-width (Unicode NFKC subset) -->
>     <filter class="solr.CJKWidthFilterFactory"/>
>     <!-- Lower-case romaji characters -->
>     <filter class="solr.LowerCaseFilterFactory"/>
>   </analyzer>
> </fieldType>
> {code}

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