Class JapaneseTokenizerFactory
- java.lang.Object
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- org.apache.lucene.analysis.AbstractAnalysisFactory
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- org.apache.lucene.analysis.TokenizerFactory
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- org.apache.lucene.analysis.ja.JapaneseTokenizerFactory
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- All Implemented Interfaces:
ResourceLoaderAware
public class JapaneseTokenizerFactory extends TokenizerFactory implements ResourceLoaderAware
Factory forJapaneseTokenizer
.<fieldType name="text_ja" class="solr.TextField"> <analyzer> <tokenizer class="solr.JapaneseTokenizerFactory" mode="NORMAL" userDictionary="user.txt" userDictionaryEncoding="UTF-8" discardPunctuation="true" discardCompoundToken="false" /> <filter class="solr.JapaneseBaseFormFilterFactory"/> </analyzer> </fieldType>
Additional expert user parameters nBestCost and nBestExamples can be used to include additional searchable tokens that those most likely according to the statistical model. A typical use-case for this is to improve recall and make segmentation more resilient to mistakes. The feature can also be used to get a decompounding effect.
The nBestCost parameter specifies an additional Viterbi cost, and when used, JapaneseTokenizer will include all tokens in Viterbi paths that are within the nBestCost value of the best path.
Finding a good value for nBestCost can be difficult to do by hand. The nBestExamples parameter can be used to find an nBestCost value based on examples with desired segmentation outcomes.
For example, a value of /箱根山-箱根/成田空港-成田/ indicates that in the texts, 箱根山 (Mt. Hakone) and 成田空港 (Narita Airport) we'd like a cost that gives is us 箱根 (Hakone) and 成田 (Narita). Notice that costs are estimated for each example individually, and the maximum nBestCost found across all examples is used.
If both nBestCost and nBestExamples is used in a configuration, the largest value of the two is used.
Parameters nBestCost and nBestExamples work with all tokenizer modes, but it makes the most sense to use them with NORMAL mode.
- Since:
- 3.6.0
- SPI Name (case-insensitive: if the name is 'htmlStrip', 'htmlstrip' can be used when looking up the service).
- "japanese"
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Field Summary
Fields Modifier and Type Field Description static String
NAME
SPI name-
Fields inherited from class org.apache.lucene.analysis.AbstractAnalysisFactory
LUCENE_MATCH_VERSION_PARAM, luceneMatchVersion
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Constructor Summary
Constructors Constructor Description JapaneseTokenizerFactory()
Default ctor for compatibility with SPIJapaneseTokenizerFactory(Map<String,String> args)
Creates a new JapaneseTokenizerFactory
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description JapaneseTokenizer
create(AttributeFactory factory)
void
inform(ResourceLoader loader)
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Methods inherited from class org.apache.lucene.analysis.TokenizerFactory
availableTokenizers, create, findSPIName, forName, lookupClass, reloadTokenizers
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Methods inherited from class org.apache.lucene.analysis.AbstractAnalysisFactory
defaultCtorException, get, get, get, get, get, getBoolean, getChar, getClassArg, getFloat, getInt, getLines, getLuceneMatchVersion, getOriginalArgs, getPattern, getSet, getSnowballWordSet, getWordSet, isExplicitLuceneMatchVersion, require, require, require, requireBoolean, requireChar, requireFloat, requireInt, setExplicitLuceneMatchVersion, splitAt, splitFileNames
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Field Detail
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NAME
public static final String NAME
SPI name- See Also:
- Constant Field Values
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Method Detail
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inform
public void inform(ResourceLoader loader) throws IOException
- Specified by:
inform
in interfaceResourceLoaderAware
- Throws:
IOException
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create
public JapaneseTokenizer create(AttributeFactory factory)
- Specified by:
create
in classTokenizerFactory
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