Package org.apache.lucene.analysis.util

Class SegmentingTokenizerBase

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.Tokenizer

org.apache.lucene.analysis.util.SegmentingTokenizerBase

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

ThaiTokenizer

public abstract class SegmentingTokenizerBase
extends Tokenizer

Breaks text into sentences with a BreakIterator and allows subclasses to decompose these sentences into words.

This can be used by subclasses that need sentence context for tokenization purposes, such as CJK segmenters.

Additionally it can be used by subclasses that want to mark sentence boundaries (with a custom attribute, extra token, position increment, etc) for downstream processing.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

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

AttributeSource.State

Field Summary

Fields

Modifier and Type	Field	Description
protected final char[]	buffer
static final int	BUFFERMAX
protected int	offset	accumulated offset of previous buffers for this reader, for offsetAtt

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	Description
SegmentingTokenizerBase(BreakIterator iterator)	Construct a new SegmenterBase, using the provided BreakIterator for sentence segmentation.
SegmentingTokenizerBase(BreakIterator iterator, int bufferSize)	Construct a new SegmenterBase, using the provided BreakIterator and buffer size.
SegmentingTokenizerBase(AttributeFactory factory, BreakIterator iterator)	Construct a new SegmenterBase, also supplying the AttributeFactory
SegmentingTokenizerBase(AttributeFactory factory, BreakIterator iterator, int bufferSize)	Construct a new SegmenterBase, supplying the AttributeFactory, BreakIterator, and buffer size.

Method Summary

Modifier and Type	Method	Description
final void	end()
final boolean	incrementToken()
protected abstract boolean	incrementWord()	Returns true if another word is available
protected boolean	isSafeEnd(char ch)	For sentence tokenization, these are the unambiguous break positions.
void	reset()
protected abstract void	setNextSentence(int sentenceStart, int sentenceEnd)	Provides the next input sentence for analysis

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

close, correctOffset, setReader, setReaderTestPoint

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

Field Details

BUFFERMAX

public static final int BUFFERMAX

See Also:

• Constant Field Values

buffer

protected final char[] buffer

offset

protected int offset

accumulated offset of previous buffers for this reader, for offsetAtt

Constructor Details

SegmentingTokenizerBase

public SegmentingTokenizerBase(BreakIterator iterator)

Construct a new SegmenterBase, using the provided BreakIterator for sentence segmentation.

Note that you should never share BreakIterators across different TokenStreams, instead a newly created or cloned one should always be provided to this constructor.

SegmentingTokenizerBase

public SegmentingTokenizerBase(BreakIterator iterator,
 int bufferSize)

Construct a new SegmenterBase, using the provided BreakIterator and buffer size.

Parameters:

iterator - BreakIterator for sentence segmentation

bufferSize - internal buffer size in characters

SegmentingTokenizerBase

public SegmentingTokenizerBase(AttributeFactory factory,
 BreakIterator iterator)

Construct a new SegmenterBase, also supplying the AttributeFactory

SegmentingTokenizerBase

public SegmentingTokenizerBase(AttributeFactory factory,
 BreakIterator iterator,
 int bufferSize)

Construct a new SegmenterBase, supplying the AttributeFactory, BreakIterator, and buffer size.

Parameters:

factory - AttributeFactory to use

iterator - BreakIterator for sentence segmentation

bufferSize - internal buffer size in characters

Method Details

incrementToken

public final boolean incrementToken()
                             throws IOException

Specified by:

incrementToken in class TokenStream

Throws:

IOException

reset

public void reset()
           throws IOException

Overrides:

reset in class Tokenizer

Throws:

IOException

end

public final void end()
               throws IOException

Overrides:

end in class TokenStream

Throws:

IOException

isSafeEnd

protected boolean isSafeEnd(char ch)

For sentence tokenization, these are the unambiguous break positions.

setNextSentence

protected abstract void setNextSentence(int sentenceStart,
 int sentenceEnd)

Provides the next input sentence for analysis

incrementWord

protected abstract boolean incrementWord()

Returns true if another word is available