org.apache.lucene.analysis.core

Class LowerCaseTokenizer

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.Tokenizer

org.apache.lucene.analysis.util.CharTokenizer

org.apache.lucene.analysis.core.LetterTokenizer

org.apache.lucene.analysis.core.LowerCaseTokenizer

All Implemented Interfaces:

Closeable, AutoCloseable

public final class LowerCaseTokenizer
extends LetterTokenizer

LowerCaseTokenizer performs the function of LetterTokenizer and LowerCaseFilter together. It divides text at non-letters and converts them to lower case. While it is functionally equivalent to the combination of LetterTokenizer and LowerCaseFilter, there is a performance advantage to doing the two tasks at once, hence this (redundant) implementation.

Note: this does a decent job for most European languages, but does a terrible job for some Asian languages, where words are not separated by spaces.

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.util.CharTokenizer

DEFAULT_MAX_WORD_LEN

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

input

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

DEFAULT_TOKEN_ATTRIBUTE_FACTORY

Constructor Summary

Constructors

Constructor and Description
LowerCaseTokenizer() Construct a new LowerCaseTokenizer.
LowerCaseTokenizer(AttributeFactory factory) Construct a new LowerCaseTokenizer using a given AttributeFactory.
LowerCaseTokenizer(AttributeFactory factory, int maxTokenLen) Construct a new LowerCaseTokenizer using a given AttributeFactory.

Method Summary

Modifier and Type	Method and Description
protected int	normalize(int c) Converts char to lower case Character.toLowerCase(int).

Methods inherited from class org.apache.lucene.analysis.core.LetterTokenizer

isTokenChar

Methods inherited from class org.apache.lucene.analysis.util.CharTokenizer

end, fromSeparatorCharPredicate, fromSeparatorCharPredicate, fromSeparatorCharPredicate, fromSeparatorCharPredicate, fromTokenCharPredicate, fromTokenCharPredicate, fromTokenCharPredicate, fromTokenCharPredicate, incrementToken, reset

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

close, correctOffset, setReader

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

LowerCaseTokenizer

public LowerCaseTokenizer()

Construct a new LowerCaseTokenizer.

LowerCaseTokenizer

public LowerCaseTokenizer(AttributeFactory factory)

Construct a new LowerCaseTokenizer using a given AttributeFactory.

Parameters:

factory - the attribute factory to use for this Tokenizer

LowerCaseTokenizer

public LowerCaseTokenizer(AttributeFactory factory,
                          int maxTokenLen)

Construct a new LowerCaseTokenizer using a given AttributeFactory.

Parameters:

factory - the attribute factory to use for this Tokenizer

maxTokenLen - maximum token length the tokenizer will emit. Must be greater than 0 and less than MAX_TOKEN_LENGTH_LIMIT (1024*1024)

Throws:

IllegalArgumentException - if maxTokenLen is invalid.

Method Detail

normalize

protected int normalize(int c)

Converts char to lower case Character.toLowerCase(int).

Overrides:

normalize in class CharTokenizer