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