org.apache.lucene.collation

Class ICUCollationKeyFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.collation.ICUCollationKeyFilter

All Implemented Interfaces:

Closeable

Deprecated.

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

@Deprecated
public final class ICUCollationKeyFilter
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. RuleBasedCollators 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):

1. Collator version - see Collator.getVersion()
2. 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 ICUCollationKeyFilter to generate index terms, do not use CollationKeyFilter on the query side, or vice versa.

ICUCollationKeyFilter is 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.

Nested Class Summary

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

AttributeSource.AttributeFactory, AttributeSource.State

Field Summary

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

input

Constructor Summary

Constructors

Constructor and Description
ICUCollationKeyFilter(TokenStream input, com.ibm.icu.text.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

ICUCollationKeyFilter

public ICUCollationKeyFilter(TokenStream input,
                     com.ibm.icu.text.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