Class CollationKeyAnalyzer
- java.lang.Object
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- org.apache.lucene.analysis.Analyzer
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- org.apache.lucene.collation.CollationKeyAnalyzer
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class CollationKeyAnalyzer extends Analyzer
ConfiguresKeywordTokenizer
withCollationAttributeFactory
.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. Since
RuleBasedCollator
s are not independently versioned, it is unsafe to search against stored CollationKeys unless 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):- JVM vendor
- JVM version, including patch version
- The language (and country and variant, if specified) of the Locale used when constructing
the collator via
Collator.getInstance(java.util.Locale)
. - The collation strength used - see
Collator.setStrength(int)
The
ICUCollationKeyAnalyzer
in the analysis-icu package uses ICU4J's Collator, which makes its version available, thus allowing collation to be versioned independently from the JVM. ICUCollationKeyAnalyzer is also 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.CollationKeys generated by java.text.Collators are not compatible with those those generated by ICU Collators. Specifically, if you use CollationKeyAnalyzer to generate index terms, do not use ICUCollationKeyAnalyzer on the query side, or vice versa.
- 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 CollationKeyAnalyzer(Collator collator)
Create a new CollationKeyAnalyzer, using the specified collator.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected AttributeFactory
attributeFactory(String fieldName)
protected Analyzer.TokenStreamComponents
createComponents(String fieldName)
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Methods inherited from class org.apache.lucene.analysis.Analyzer
close, getOffsetGap, getPositionIncrementGap, getReuseStrategy, initReader, initReaderForNormalization, normalize, normalize, tokenStream, tokenStream
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Constructor Detail
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CollationKeyAnalyzer
public CollationKeyAnalyzer(Collator collator)
Create a new CollationKeyAnalyzer, using the specified collator.- Parameters:
collator
- CollationKey generator
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Method Detail
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attributeFactory
protected AttributeFactory attributeFactory(String fieldName)
- Overrides:
attributeFactory
in classAnalyzer
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createComponents
protected Analyzer.TokenStreamComponents createComponents(String fieldName)
- Specified by:
createComponents
in classAnalyzer
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