Class ICUCollationKeyAnalyzer
- All Implemented Interfaces:
Closeable
,AutoCloseable
KeywordTokenizer
with ICUCollationAttributeFactory
.
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
-
Nested Class Summary
Nested classes/interfaces inherited from class org.apache.lucene.analysis.Analyzer
Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents
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Field Summary
Fields inherited from class org.apache.lucene.analysis.Analyzer
GLOBAL_REUSE_STRATEGY, PER_FIELD_REUSE_STRATEGY
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Constructor Summary
ConstructorDescriptionICUCollationKeyAnalyzer
(com.ibm.icu.text.Collator collator) Create a new ICUCollationKeyAnalyzer, using the specified collator. -
Method Summary
Modifier and TypeMethodDescriptionprotected Analyzer.TokenStreamComponents
createComponents
(String fieldName) Methods inherited from class org.apache.lucene.analysis.Analyzer
attributeFactory, close, getOffsetGap, getPositionIncrementGap, getReuseStrategy, initReader, initReaderForNormalization, normalize, normalize, tokenStream, tokenStream
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Constructor Details
-
ICUCollationKeyAnalyzer
public ICUCollationKeyAnalyzer(com.ibm.icu.text.Collator collator) Create a new ICUCollationKeyAnalyzer, using the specified collator.- Parameters:
collator
- CollationKey generator
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Method Details
-
createComponents
- Specified by:
createComponents
in classAnalyzer
-