Documentation of 'org.apache.lucene.analysis.standard.StandardTokenizer' Java class
StandardTokenizer
Skip navigation links
org.apache.lucene.analysis.standard

Class StandardTokenizer


  • public class StandardTokenizer
extends Tokenizer
    A grammar-based tokenizer constructed with JFlex

    This should be a good tokenizer for most European-language documents:

    • Splits words at punctuation characters, removing punctuation. However, a dot that's not followed by whitespace is considered part of a token.
    • Splits words at hyphens, unless there's a number in the token, in which case the whole token is interpreted as a product number and is not split.
    • Recognizes email addresses and internet hostnames as one token.

    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.

    • Field Summary

      Fields 
      Modifier and Type Field and Description
      static int ACRONYM 
      static int ACRONYM_DEP
      Deprecated. 
      this solves a bug where HOSTs that end with '.' are identified as ACRONYMs. It is deprecated and will be removed in the next release.
      static int ALPHANUM 
      static int APOSTROPHE 
      static int CJ 
      static int COMPANY 
      static int EMAIL 
      static int HOST 
      static int NUM 
      static java.lang.String[] TOKEN_TYPES
      String token types that correspond to token type int constants
      static java.lang.String[] tokenImage
      Deprecated. 
      Please use TOKEN_TYPES instead

    • Method Summary

      All Methods Instance Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method and Description
      int getMaxTokenLength() 
      boolean isReplaceInvalidAcronym()
      Deprecated. 
      Remove in 3.X and make true the only valid value
      Token next(Token result)
      Returns the next token in the stream, or null at EOS.
      void reset()
      Resets this stream to the beginning.
      void reset(java.io.Reader reader)
      Expert: Reset the tokenizer to a new reader.
      void setMaxTokenLength(int length)
      Set the max allowed token length.
      void setReplaceInvalidAcronym(boolean replaceInvalidAcronym)
      Deprecated. 
      Remove in 3.X and make true the only valid value See https://issues.apache.org/jira/browse/LUCENE-1068

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • StandardTokenizer

        public StandardTokenizer(java.io.Reader input)
        Creates a new instance of the StandardTokenizer. Attaches the input to a newly created JFlex scanner.

      • StandardTokenizer

        public StandardTokenizer(java.io.Reader input,
                         boolean replaceInvalidAcronym)
        Creates a new instance of the StandardTokenizer. Attaches the input to the newly created JFlex scanner.
        Parameters:
        input - The input reader
        replaceInvalidAcronym - Set to true to replace mischaracterized acronyms with HOST. See http://issues.apache.org/jira/browse/LUCENE-1068

    • Method Detail

      • setMaxTokenLength

        public void setMaxTokenLength(int length)
        Set the max allowed token length. Any token longer than this is skipped.

      • next

        public Token next(Token result)
           throws java.io.IOException
        Description copied from class: TokenStream
        Returns the next token in the stream, or null at EOS. When possible, the input Token should be used as the returned Token (this gives fastest tokenization performance), but this is not required and a new Token may be returned. Callers may re-use a single Token instance for successive calls to this method.

        This implicitly defines a "contract" between consumers (callers of this method) and producers (implementations of this method that are the source for tokens):

        • A consumer must fully consume the previously returned Token before calling this method again.
        • A producer must call Token.clear() before setting the fields in it & returning it
        Note that a TokenFilter is considered a consumer.
        Overrides:
        next in class TokenStream
        Parameters:
        result - a Token that may or may not be used to return
        Returns:
        next token in the stream or null if end-of-stream was hit
        Throws:
        java.io.IOException

      • reset

        public void reset()
           throws java.io.IOException
        Description copied from class: TokenStream
        Resets this stream to the beginning. This is an optional operation, so subclasses may or may not implement this method. Reset() is not needed for the standard indexing process. However, if the Tokens of a TokenStream are intended to be consumed more than once, it is necessary to implement reset().
        Overrides:
        reset in class TokenStream
        Throws:
        java.io.IOException

      • reset

        public void reset(java.io.Reader reader)
           throws java.io.IOException
        Description copied from class: Tokenizer
        Expert: Reset the tokenizer to a new reader. Typically, an analyzer (in its reusableTokenStream method) will use this to re-use a previously created tokenizer.
        Overrides:
        reset in class Tokenizer
        Throws:
        java.io.IOException

      • isReplaceInvalidAcronym

        public boolean isReplaceInvalidAcronym()
        Deprecated. Remove in 3.X and make true the only valid value
        Prior to https://issues.apache.org/jira/browse/LUCENE-1068, StandardTokenizer mischaracterized as acronyms tokens like www.abc.com when they should have been labeled as hosts instead.
        Returns:
        true if StandardTokenizer now returns these tokens as Hosts, otherwise false

      • setReplaceInvalidAcronym

        public void setReplaceInvalidAcronym(boolean replaceInvalidAcronym)
        Deprecated. Remove in 3.X and make true the only valid value See https://issues.apache.org/jira/browse/LUCENE-1068
        Parameters:
        replaceInvalidAcronym - Set to true to replace mischaracterized acronyms as HOST.
Skip navigation links

DataMelt 3.0 © DataMelt by jWork.ORG

You see the box below because you did not login.