Package org.apache.lucene.analysis.email

Class UAX29URLEmailTokenizerImpl

  • public final class UAX29URLEmailTokenizerImpl
extends Object
    This class implements Word Break rules from the Unicode Text Segmentation algorithm, as specified in Unicode Standard Annex #29 URLs and email addresses are also tokenized according to the relevant RFCs.

    Tokens produced are of the following types:

    • <ALPHANUM>: A sequence of alphabetic and numeric characters
    • <NUM>: A number
    • <URL>: A URL
    • <EMAIL>: An email address
    • <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
    • <EMOJI>: A sequence of Emoji characters

    • 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

      • 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

    • Constructor Detail

      • UAX29URLEmailTokenizerImpl

        public UAX29URLEmailTokenizerImpl​(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

      • 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