org.apache.lucene.analysis
Class LowerCaseTokenizer

java.lang.Object
  org.apache.lucene.util.AttributeSource
      org.apache.lucene.analysis.TokenStream
          org.apache.lucene.analysis.Tokenizer
              org.apache.lucene.analysis.CharTokenizer
                  org.apache.lucene.analysis.LetterTokenizer
                      org.apache.lucene.analysis.LowerCaseTokenizer

All Implemented Interfaces:

Closeable

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.

You must specify the required Version compatibility when creating LowerCaseTokenizer:

• As of 3.1, CharTokenizer uses an int based API to normalize and detect token characters. See CharTokenizer.isTokenChar(int) and CharTokenizer.normalize(int) for details.

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.Tokenizer

input

Constructor Summary

LowerCaseTokenizer(AttributeSource.AttributeFactory factory, Reader in)
Deprecated. use LowerCaseTokenizer(Version, AttributeSource.AttributeFactory, Reader) instead. This will be removed in Lucene 4.0.

LowerCaseTokenizer(AttributeSource source, Reader in)
Deprecated. use LowerCaseTokenizer(Version, AttributeSource, Reader) instead. This will be removed in Lucene 4.0.

LowerCaseTokenizer(Reader in)
Deprecated. use LowerCaseTokenizer(Version, Reader) instead. This will be removed in Lucene 4.0.

LowerCaseTokenizer(Version matchVersion, AttributeSource.AttributeFactory factory, Reader in)
Construct a new LowerCaseTokenizer using a given AttributeSource.AttributeFactory.

LowerCaseTokenizer(Version matchVersion, AttributeSource source, Reader in)
Construct a new LowerCaseTokenizer using a given AttributeSource.

LowerCaseTokenizer(Version matchVersion, Reader in)
Construct a new LowerCaseTokenizer.

Method Summary

protected int

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

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

isTokenChar

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

end, incrementToken, isTokenChar, normalize, reset

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

close, correctOffset

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

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

LowerCaseTokenizer

public LowerCaseTokenizer(Version matchVersion,
                          Reader in)

Construct a new LowerCaseTokenizer.

Parameters:

matchVersion - Lucene version to match See above

in - the input to split up into tokens

LowerCaseTokenizer

public LowerCaseTokenizer(Version matchVersion,
                          AttributeSource source,
                          Reader in)

Construct a new LowerCaseTokenizer using a given AttributeSource.

Parameters:

matchVersion - Lucene version to match See above

source - the attribute source to use for this Tokenizer

in - the input to split up into tokens

LowerCaseTokenizer

public LowerCaseTokenizer(Version matchVersion,
                          AttributeSource.AttributeFactory factory,
                          Reader in)

Construct a new LowerCaseTokenizer using a given AttributeSource.AttributeFactory.

Parameters:

matchVersion - Lucene version to match See above

factory - the attribute factory to use for this Tokenizer

in - the input to split up into tokens

LowerCaseTokenizer

@Deprecated
public LowerCaseTokenizer(Reader in)

Deprecated. use LowerCaseTokenizer(Version, Reader) instead. This will be removed in Lucene 4.0.

Construct a new LowerCaseTokenizer.

LowerCaseTokenizer

@Deprecated
public LowerCaseTokenizer(AttributeSource source,
                                     Reader in)

Deprecated. use LowerCaseTokenizer(Version, AttributeSource, Reader) instead. This will be removed in Lucene 4.0.

Construct a new LowerCaseTokenizer using a given AttributeSource.

LowerCaseTokenizer

@Deprecated
public LowerCaseTokenizer(AttributeSource.AttributeFactory factory,
                                     Reader in)

Deprecated. use LowerCaseTokenizer(Version, AttributeSource.AttributeFactory, Reader) instead. This will be removed in Lucene 4.0.

Construct a new LowerCaseTokenizer using a given AttributeSource.AttributeFactory.

Method Detail

normalize

protected int normalize(int c)

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

Overrides:

normalize in class CharTokenizer