public class CollationAttributeFactory extends AttributeFactory.StaticImplementationAttributeFactory<CollatedTermAttributeImpl>
Converts each token into its
CollationKey, and then
encodes the 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. Since
RuleBasedCollators 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):
ICUCollationAttributeFactory in the analysis-icu package
uses ICU4J's Collator, which makes its
version available, thus allowing collation to be versioned independently
from the JVM. ICUCollationAttributeFactory is also 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.
CollationKeys generated by java.text.Collators are not compatible with those those generated by ICU Collators. Specifically, if you use CollationAttributeFactory to generate index terms, do not use ICUCollationAttributeFactory on the query side, or vice versa.
AttributeFactory.StaticImplementationAttributeFactory<A extends AttributeImpl>
|Constructor and Description|
Create a CollationAttributeFactory, using the supplied Attribute Factory as the factory for all other attributes.
Create a CollationAttributeFactory, using
|Modifier and Type||Method and Description|
Creates an instance of
createAttributeInstance, equals, hashCode
public CollationAttributeFactory(Collator collator)
TokenStream.DEFAULT_TOKEN_ATTRIBUTE_FACTORYas the factory for all other attributes.
collator- CollationKey generator
public CollatedTermAttributeImpl createInstance()