org.apache.lucene.collation

Class CollationKeyFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.collation.CollationKeyFilter

All Implemented Interfaces:

Closeable, AutoCloseable

Deprecated.

Use CollationAttributeFactory instead, which encodes terms directly as bytes. This filter will be removed in Lucene 5.0

@Deprecated
public final class CollationKeyFilter
extends TokenFilter

Converts each token into its CollationKey, and then encodes the CollationKey with IndexableBinaryStringTools, 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 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):

1. JVM vendor
2. JVM version, including patch version
3. The language (and country and variant, if specified) of the Locale used when constructing the collator via Collator.getInstance(java.util.Locale).
4. The collation strength used - see Collator.setStrength(int)

The ICUCollationKeyFilter in the analysis-icu package uses ICU4J's Collator, which makes its version available, thus allowing collation to be versioned independently from the JVM. ICUCollationKeyFilter is also significantly faster and generates significantly shorter keys than CollationKeyFilter. 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 CollationKeyFilter to generate index terms, do not use ICUCollationKeyFilter on the query side, or vice versa.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

AttributeSource.State

Field Summary

Fields inherited from class org.apache.lucene.analysis.TokenFilter

input

Fields inherited from class org.apache.lucene.analysis.TokenStream

DEFAULT_TOKEN_ATTRIBUTE_FACTORY

Fields inherited from class org.apache.lucene.util.AttributeSource

DEFAULT_ATTRIBUTE_FACTORY

Constructor Summary

Constructors

Constructor and Description
CollationKeyFilter(TokenStream input, Collator collator) Deprecated.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	incrementToken() Deprecated.

Methods inherited from class org.apache.lucene.analysis.TokenFilter

close, end, reset

Methods inherited from class org.apache.lucene.util.AttributeSource

addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

CollationKeyFilter

public CollationKeyFilter(TokenStream input,
                  Collator collator)

Deprecated.

Parameters:

input - Source token stream

collator - CollationKey generator

Method Detail

incrementToken

public boolean incrementToken()
                       throws IOException

Deprecated.

Specified by:

incrementToken in class TokenStream

Throws:

IOException