Class ICUCollationKeyAnalyzer
- java.lang.Object
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- org.apache.lucene.analysis.Analyzer
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- org.apache.lucene.analysis.icu.ICUCollationKeyAnalyzer
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class ICUCollationKeyAnalyzer extends Analyzer
ConfiguresKeywordTokenizer
withICUCollationAttributeFactory
.Converts the token into its
CollationKey
, and then encodes the CollationKey directly to allow it to be stored as an index term.WARNING: Make sure you use exactly the same Collator at index and query time -- CollationKeys are only comparable when produced by the same Collator.
RuleBasedCollator
s are independently versioned, so it is safe to search against stored CollationKeys if the following are exactly the same (best practice is to store this information with the index and check that they remain the same at query time):- Collator version - see
Collator.getVersion()
- The collation strength used - see
Collator.setStrength(int)
CollationKeys generated by ICU Collators are not compatible with those generated by java.text.Collators. Specifically, if you use ICUCollationKeyAnalyzer to generate index terms, do not use
CollationKeyAnalyzer
on the query side, or vice versa.ICUCollationKeyAnalyzer is significantly faster and generates significantly shorter keys than CollationKeyAnalyzer. See http://site.icu-project.org/charts/collation-icu4j-sun for key generation timing and key length comparisons between ICU4J and java.text.Collator over several languages.
- Since:
- 3.1
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.analysis.Analyzer
Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents
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Field Summary
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Fields inherited from class org.apache.lucene.analysis.Analyzer
GLOBAL_REUSE_STRATEGY, PER_FIELD_REUSE_STRATEGY
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Constructor Summary
Constructors Constructor Description ICUCollationKeyAnalyzer(com.ibm.icu.text.Collator collator)
Create a new ICUCollationKeyAnalyzer, using the specified collator.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected Analyzer.TokenStreamComponents
createComponents(String fieldName)
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Methods inherited from class org.apache.lucene.analysis.Analyzer
attributeFactory, close, getOffsetGap, getPositionIncrementGap, getReuseStrategy, initReader, initReaderForNormalization, normalize, normalize, tokenStream, tokenStream
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Method Detail
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createComponents
protected Analyzer.TokenStreamComponents createComponents(String fieldName)
- Specified by:
createComponents
in classAnalyzer
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