public final class ICUCollationKeyAnalyzer extends Analyzer
Configures 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.getVersion()
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.
Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents
GLOBAL_REUSE_STRATEGY, PER_FIELD_REUSE_STRATEGY
Constructor and Description |
---|
ICUCollationKeyAnalyzer(com.ibm.icu.text.Collator collator)
Create a new ICUCollationKeyAnalyzer, using the specified collator.
|
Modifier and Type | Method and Description |
---|---|
protected Analyzer.TokenStreamComponents |
createComponents(String fieldName) |
attributeFactory, close, getOffsetGap, getPositionIncrementGap, getReuseStrategy, getVersion, initReader, initReaderForNormalization, normalize, normalize, setVersion, tokenStream, tokenStream
public ICUCollationKeyAnalyzer(com.ibm.icu.text.Collator collator)
collator
- CollationKey generatorprotected Analyzer.TokenStreamComponents createComponents(String fieldName)
createComponents
in class Analyzer
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