Class ICUCollationAttributeFactory
CollationKey
, and then encodes bytes 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 ICUCollationAttributeFactory to generate index
terms, do not use CollationAttributeFactory
on the query side, or vice versa.
ICUCollationAttributeFactory is significantly faster and generates significantly shorter keys than CollationAttributeFactory. 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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Nested Class Summary
Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeFactory
AttributeFactory.StaticImplementationAttributeFactory<A extends AttributeImpl>
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Field Summary
Fields inherited from class org.apache.lucene.util.AttributeFactory
DEFAULT_ATTRIBUTE_FACTORY
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Constructor Summary
ConstructorDescriptionICUCollationAttributeFactory
(com.ibm.icu.text.Collator collator) Create an ICUCollationAttributeFactory, usingTokenStream.DEFAULT_TOKEN_ATTRIBUTE_FACTORY
as the factory for all other attributes.ICUCollationAttributeFactory
(AttributeFactory delegate, com.ibm.icu.text.Collator collator) Create an ICUCollationAttributeFactory, using the supplied Attribute Factory as the factory for all other attributes. -
Method Summary
Methods inherited from class org.apache.lucene.util.AttributeFactory.StaticImplementationAttributeFactory
createAttributeInstance, equals, hashCode
Methods inherited from class org.apache.lucene.util.AttributeFactory
getStaticImplementation
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Constructor Details
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ICUCollationAttributeFactory
public ICUCollationAttributeFactory(com.ibm.icu.text.Collator collator) Create an ICUCollationAttributeFactory, usingTokenStream.DEFAULT_TOKEN_ATTRIBUTE_FACTORY
as the factory for all other attributes.- Parameters:
collator
- CollationKey generator
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ICUCollationAttributeFactory
Create an ICUCollationAttributeFactory, using the supplied Attribute Factory as the factory for all other attributes.- Parameters:
delegate
- Attribute Factorycollator
- CollationKey generator
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Method Details
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createInstance
- Specified by:
createInstance
in classAttributeFactory.StaticImplementationAttributeFactory<ICUCollatedTermAttributeImpl>
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