Package org.apache.lucene.analysis.standard

Class StandardTokenizerImpl

  • All Implemented Interfaces:
    StandardTokenizerInterface
    public final class StandardTokenizerImpl
extends java.lang.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
    • <KATAKANA>: A sequence of katakana characters
    • <HANGUL>: A sequence of Hangul characters

    • Constructor Summary

      Constructors 
      Constructor Description
      StandardTokenizerImpl​(java.io.Reader in)
      Creates a new scanner

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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 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​(java.io.Reader reader)
      Resets the scanner to read from a new input stream.
      int yystate()
      Returns the current lexical state.
      java.lang.String yytext()
      Returns the text matched by the current regular expression.

      • Methods inherited from class java.lang.Object

        equals, 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

      • 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

    • Constructor Detail

      • StandardTokenizerImpl

        public StandardTokenizerImpl​(java.io.Reader in)
        Creates a new scanner
        Parameters:
        in - the java.io.Reader to read input from.

    • Method Detail

      • yyclose

        public final void yyclose()
                   throws java.io.IOException
        Closes the input stream.
        Throws:
        java.io.IOException

      • yyreset

        public final void yyreset​(java.io.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 java.lang.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

      • 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 java.io.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:
        java.io.IOException - if any I/O-Error occurs