org.apache.lucene.analysis.standard
Class StandardTokenizerImpl

java.lang.Object
  org.apache.lucene.analysis.standard.StandardTokenizerImpl

All Implemented Interfaces:

StandardTokenizerInterface

public final class StandardTokenizerImpl
extends Object
implements StandardTokenizerInterface

This class implements Word Break rules from the Unicode Text Segmentation algorithm, as specified in Unicode Standard Annex #29

Tokens produced are of the following types:

• <ALPHANUM>: A sequence of alphabetic and numeric characters
• <NUM>: A number
• <SOUTHEAST_ASIAN>: A sequence of characters from South and Southeast Asian languages, including Thai, Lao, Myanmar, and Khmer
• <IDEOGRAPHIC>: A single CJKV ideographic character
• <HIRAGANA>: A single hiragana character

Field Summary

static int	HANGUL_TYPE
static int	HIRAGANA_TYPE
static int	IDEOGRAPHIC_TYPE
static int	KATAKANA_TYPE
static int	NUMERIC_TYPE Numbers
static int	SOUTH_EAST_ASIAN_TYPE Chars in class \p{Line_Break = Complex_Context} are from South East Asian scripts (Thai, Lao, Myanmar, Khmer, etc.).
static int	WORD_TYPE Alphanumeric sequences
static int	YYEOF This character denotes the end of file
static int	YYINITIAL lexical states

Constructor Summary

StandardTokenizerImpl(InputStream in)
Creates a new scanner.

StandardTokenizerImpl(Reader in)
Creates a new scanner There is also a java.io.InputStream version of this constructor.

Method Summary

int	getNextToken() Resumes scanning until the next regular expression is matched, the end of input is encountered or an I/O-Error occurs.
void	getText(CharTermAttribute t) Fills CharTermAttribute with the current token text.
void	yybegin(int newState) Enters a new lexical state
int	yychar() Returns the current position.
char	yycharat(int pos) Returns the character at position pos from the matched text.
void	yyclose() Closes the input stream.
int	yylength() Returns the length of the matched text region.
void	yypushback(int number) Pushes the specified amount of characters back into the input stream.
void	yyreset(Reader reader) Resets the scanner to read from a new input stream.
int	yystate() Returns the current lexical state.
String	yytext() Returns the text matched by the current regular expression.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

YYEOF

public static final int YYEOF

This character denotes the end of file

See Also:

Constant Field Values

YYINITIAL

public static final int YYINITIAL

lexical states

See Also:

Constant Field Values

WORD_TYPE

public static final int WORD_TYPE

Alphanumeric sequences

See Also:

Constant Field Values

NUMERIC_TYPE

public static final int NUMERIC_TYPE

Numbers

See Also:

Constant Field Values

SOUTH_EAST_ASIAN_TYPE

public static final int SOUTH_EAST_ASIAN_TYPE

Chars in class \p{Line_Break = Complex_Context} are from South East Asian scripts (Thai, Lao, Myanmar, Khmer, etc.). Sequences of these are kept together as as a single token rather than broken up, because the logic required to break them at word boundaries is too complex for UAX#29.

See Unicode Line Breaking Algorithm: http://www.unicode.org/reports/tr14/#SA

See Also:

Constant Field Values

IDEOGRAPHIC_TYPE

public static final int IDEOGRAPHIC_TYPE

See Also:

Constant Field Values

HIRAGANA_TYPE

public static final int HIRAGANA_TYPE

See Also:

Constant Field Values

KATAKANA_TYPE

public static final int KATAKANA_TYPE

See Also:

Constant Field Values

HANGUL_TYPE

public static final int HANGUL_TYPE

See Also:

Constant Field Values

Constructor Detail

StandardTokenizerImpl

public StandardTokenizerImpl(Reader in)

Creates a new scanner There is also a java.io.InputStream version of this constructor.

Parameters:

in - the java.io.Reader to read input from.

StandardTokenizerImpl

public StandardTokenizerImpl(InputStream in)

Creates a new scanner. There is also java.io.Reader version of this constructor.

Parameters:

in - the java.io.Inputstream to read input from.

Method Detail

yychar

public final int yychar()

Description copied from interface: StandardTokenizerInterface

Returns the current position.

Specified by:

yychar in interface StandardTokenizerInterface

getText

public final void getText(CharTermAttribute t)

Fills CharTermAttribute with the current token text.

Specified by:

getText in interface StandardTokenizerInterface

yyclose

public final void yyclose()
                   throws IOException

Closes the input stream.

Throws:

IOException

yyreset

public final void yyreset(Reader reader)

Resets the scanner to read from a new input stream. Does not close the old reader. All internal variables are reset, the old input stream cannot be reused (internal buffer is discarded and lost). Lexical state is set to ZZ_INITIAL. Internal scan buffer is resized down to its initial length, if it has grown.

Specified by:

yyreset in interface StandardTokenizerInterface

Parameters:

reader - the new input stream

yystate

public final int yystate()

Returns the current lexical state.

yybegin

public final void yybegin(int newState)

Enters a new lexical state

Parameters:

newState - the new lexical state

yytext

public final String yytext()

Returns the text matched by the current regular expression.

yycharat

public final char yycharat(int pos)

Returns the character at position pos from the matched text. It is equivalent to yytext().charAt(pos), but faster

Parameters:

pos - the position of the character to fetch. A value from 0 to yylength()-1.

Returns:

the character at position pos

yylength

public final int yylength()

Returns the length of the matched text region.

Specified by:

yylength in interface StandardTokenizerInterface

yypushback

public void yypushback(int number)

Pushes the specified amount of characters back into the input stream. They will be read again by then next call of the scanning method

Parameters:

number - the number of characters to be read again. This number must not be greater than yylength()!

getNextToken

public int getNextToken()
                 throws IOException

Resumes scanning until the next regular expression is matched, the end of input is encountered or an I/O-Error occurs.

Specified by:

getNextToken in interface StandardTokenizerInterface

Returns:

the next token

Throws:

IOException - if any I/O-Error occurs