Class StandardTokenizer
- java.lang.Object
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- org.apache.lucene.util.AttributeSource
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- org.apache.lucene.analysis.TokenStream
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- org.apache.lucene.analysis.Tokenizer
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- org.apache.lucene.analysis.standard.StandardTokenizer
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- All Implemented Interfaces:
Closeable,AutoCloseable
public final class StandardTokenizer extends Tokenizer
A grammar-based tokenizer constructed with JFlex.This class implements the Word Break rules from the Unicode Text Segmentation algorithm, as specified in Unicode Standard Annex #29.
Many applications have specific tokenizer needs. If this tokenizer does not suit your application, please consider copying this source code directory to your project and maintaining your own grammar-based tokenizer.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
Fields Modifier and Type Field Description static intALPHANUMAlpha/numeric token typestatic intEMOJIEmoji token type.static intHANGULHangul token typestatic intHIRAGANAHiragana token typestatic intIDEOGRAPHICIdeographic token typestatic intKATAKANAKatakana token typestatic intMAX_TOKEN_LENGTH_LIMITAbsolute maximum sized tokenstatic intNUMNumeric token typestatic intSOUTHEAST_ASIANSoutheast Asian token typestatic String[]TOKEN_TYPESString token types that correspond to token type int constants-
Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
Constructors Constructor Description StandardTokenizer()Creates a new instance of theStandardTokenizer.StandardTokenizer(AttributeFactory factory)Creates a new StandardTokenizer with a givenAttributeFactory
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description voidclose()Releases resources associated with this stream.voidend()This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()returnedfalse(using the newTokenStreamAPI).intgetMaxTokenLength()Returns the current maximum token lengthbooleanincrementToken()Consumers (i.e.,IndexWriter) use this method to advance the stream to the next token.voidreset()This method is called by a consumer before it begins consumption usingTokenStream.incrementToken().voidsetMaxTokenLength(int length)Set the max allowed token length.-
Methods inherited from class org.apache.lucene.analysis.Tokenizer
correctOffset, setReader, setReaderTestPoint
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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
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Field Detail
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ALPHANUM
public static final int ALPHANUM
Alpha/numeric token type- See Also:
- Constant Field Values
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NUM
public static final int NUM
Numeric token type- See Also:
- Constant Field Values
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SOUTHEAST_ASIAN
public static final int SOUTHEAST_ASIAN
Southeast Asian token type- See Also:
- Constant Field Values
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IDEOGRAPHIC
public static final int IDEOGRAPHIC
Ideographic token type- See Also:
- Constant Field Values
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HIRAGANA
public static final int HIRAGANA
Hiragana token type- See Also:
- Constant Field Values
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KATAKANA
public static final int KATAKANA
Katakana token type- See Also:
- Constant Field Values
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HANGUL
public static final int HANGUL
Hangul token type- See Also:
- Constant Field Values
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EMOJI
public static final int EMOJI
Emoji token type.- See Also:
- Constant Field Values
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TOKEN_TYPES
public static final String[] TOKEN_TYPES
String token types that correspond to token type int constants
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MAX_TOKEN_LENGTH_LIMIT
public static final int MAX_TOKEN_LENGTH_LIMIT
Absolute maximum sized token- See Also:
- Constant Field Values
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Constructor Detail
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StandardTokenizer
public StandardTokenizer()
Creates a new instance of theStandardTokenizer. Attaches theinputto the newly created JFlex scanner.See http://issues.apache.org/jira/browse/LUCENE-1068
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StandardTokenizer
public StandardTokenizer(AttributeFactory factory)
Creates a new StandardTokenizer with a givenAttributeFactory
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Method Detail
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setMaxTokenLength
public void setMaxTokenLength(int length)
Set the max allowed token length. Tokens larger than this will be chopped up at this token length and emitted as multiple tokens. If you need to skip such large tokens, you could increase this max length, and then useLengthFilterto remove long tokens. The default isStandardAnalyzer.DEFAULT_MAX_TOKEN_LENGTH.- Throws:
IllegalArgumentException- if the given length is outside of the range [1, 1048576].
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getMaxTokenLength
public int getMaxTokenLength()
Returns the current maximum token length- See Also:
setMaxTokenLength(int)
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incrementToken
public final boolean incrementToken() throws IOExceptionDescription copied from class:TokenStreamConsumers (i.e.,IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriateAttributeImpls with the attributes of the next token.The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use
AttributeSource.captureState()to create a copy of the current attribute state.This method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to
AttributeSource.addAttribute(Class)andAttributeSource.getAttribute(Class), references to allAttributeImpls that this stream uses should be retrieved during instantiation.To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in
TokenStream.incrementToken().- Specified by:
incrementTokenin classTokenStream- Returns:
- false for end of stream; true otherwise
- Throws:
IOException
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end
public final void end() throws IOExceptionDescription copied from class:TokenStreamThis method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()returnedfalse(using the newTokenStreamAPI). Streams implementing the old API should upgrade to use this feature.This method can be used to perform any end-of-stream operations, such as setting the final offset of a stream. The final offset of a stream might differ from the offset of the last token eg in case one or more whitespaces followed after the last token, but a WhitespaceTokenizer was used.
Additionally any skipped positions (such as those removed by a stopfilter) can be applied to the position increment, or any adjustment of other attributes where the end-of-stream value may be important.
If you override this method, always call
super.end().- Overrides:
endin classTokenStream- Throws:
IOException- If an I/O error occurs
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close
public void close() throws IOExceptionDescription copied from class:TokenizerReleases resources associated with this stream.If you override this method, always call
super.close(), otherwise some internal state will not be correctly reset (e.g.,Tokenizerwill throwIllegalStateExceptionon reuse).NOTE: The default implementation closes the input Reader, so be sure to call
super.close()when overriding this method.- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classTokenizer- Throws:
IOException
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reset
public void reset() throws IOExceptionDescription copied from class:TokenStreamThis method is called by a consumer before it begins consumption usingTokenStream.incrementToken().Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.
If you override this method, always call
super.reset(), otherwise some internal state will not be correctly reset (e.g.,Tokenizerwill throwIllegalStateExceptionon further usage).- Overrides:
resetin classTokenizer- Throws:
IOException
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