org.apache.lucene.analysis.standard

## Class StandardTokenizerImpl

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

-     public final class StandardTokenizerImpl
      extends Object

  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
  - <KATAKANA>: A sequence of katakana characters
  - <HANGUL>: A sequence of Hangul characters

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `HANGUL_TYPE` Hangul token type
    `static int` | `HIRAGANA_TYPE` Hiragana token type
    `static int` | `IDEOGRAPHIC_TYPE` Ideographic token type
    `static int` | `KATAKANA_TYPE` Katakana token 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

    Constructors
    Constructor and Description
    `StandardTokenizerImpl(Reader in)` Creates a new scanner

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `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` | `setBufferSize(int numChars)` Sets the scanner buffer size in chars
    `void` | `yybegin(int newState)` Enters a new lexical state
    `int` | `yychar()` Character count processed so far
    `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

      Ideographic token type
      See Also:
        Constant Field Values

    - #### HIRAGANA_TYPE

          public static final int HIRAGANA_TYPE

      Hiragana token type
      See Also:
        Constant Field Values

    - #### KATAKANA_TYPE

          public static final int KATAKANA_TYPE

      Katakana token type
      See Also:
        Constant Field Values

    - #### HANGUL_TYPE

          public static final int HANGUL_TYPE

      Hangul token type
      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### StandardTokenizerImpl

          public StandardTokenizerImpl(Reader in)

      Creates a new scanner
      Parameters:
        `in` - the java.io.Reader to read input from.

  - ### Method Detail

    - #### yychar

          public final int yychar()

      Character count processed so far

    - #### getText

          public final void getText(CharTermAttribute t)

      Fills CharTermAttribute with the current token text.

    - #### setBufferSize

          public final void setBufferSize(int numChars)

      Sets the scanner buffer size in chars

    - #### 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.
      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.

    - #### 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.
      Returns:
        the next token
      Throws:
        `IOException` - if any I/O-Error occurs

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