Class ICUCollationKeyAnalyzer
- java.lang.Object
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- org.apache.lucene.analysis.Analyzer
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- org.apache.lucene.collation.ICUCollationKeyAnalyzer
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class ICUCollationKeyAnalyzer extends Analyzer
Filters
KeywordTokenizer
withICUCollationKeyFilter
.Converts the token into its
CollationKey
, and then encodes the CollationKey withIndexableBinaryStringTools
, 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()
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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.
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Constructor Summary
Constructors Constructor Description ICUCollationKeyAnalyzer(com.ibm.icu.text.Collator collator)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description TokenStream
reusableTokenStream(String fieldName, Reader reader)
Creates a TokenStream that is allowed to be re-used from the previous time that the same thread called this method.TokenStream
tokenStream(String fieldName, Reader reader)
Creates a TokenStream which tokenizes all the text in the provided Reader.-
Methods inherited from class org.apache.lucene.analysis.Analyzer
close, getOffsetGap, getPositionIncrementGap, getPreviousTokenStream, setPreviousTokenStream
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Method Detail
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tokenStream
public TokenStream tokenStream(String fieldName, Reader reader)
Description copied from class:Analyzer
Creates a TokenStream which tokenizes all the text in the provided Reader. Must be able to handle null field name for backward compatibility.- Specified by:
tokenStream
in classAnalyzer
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reusableTokenStream
public TokenStream reusableTokenStream(String fieldName, Reader reader) throws IOException
Description copied from class:Analyzer
Creates a TokenStream that is allowed to be re-used from the previous time that the same thread called this method. Callers that do not need to use more than one TokenStream at the same time from this analyzer should use this method for better performance.- Overrides:
reusableTokenStream
in classAnalyzer
- Throws:
IOException
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