src/java/org/apache/lucene/analysis/Token.java

package org.apache.lucene.analysis;

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/** A Token is an occurence of a term from the text of a field.  It consists of
  a term's text, the start and end offset of the term in the text of the field,
  and a type string.

  The start and end offsets permit applications to re-associate a token with
  its source text, e.g., to display highlighted query terms in a document
  browser, or to show matching text fragments in a KWIC (KeyWord In Context)
  display, etc.

  The type is an interned string, assigned by a lexical analyzer
  (a.k.a. tokenizer), naming the lexical or syntactic class that the token
  belongs to.  For example an end of sentence marker token might be implemented
  with type "eos".  The default token type is "word".  */

public final class Token {
  String termText;				  // the text of the term
  int startOffset;				  // start in source text
  int endOffset;				  // end in source text
  String type = "word";				  // lexical type

  /** Constructs a Token with the given term text, and start & end offsets.
      The type defaults to "word." */
  public Token(String text, int start, int end) {
    termText = text;
    startOffset = start;
    endOffset = end;
  }

  /** Constructs a Token with the given text, start and end offsets, & type. */
  public Token(String text, int start, int end, String typ) {
    termText = text;
    startOffset = start;
    endOffset = end;
    type = typ;
  }

  /** Returns the Token's term text. */
  public final String termText() { return termText; }

  /** Returns this Token's starting offset, the position of the first character
    corresponding to this token in the source text.

    Note that the difference between endOffset() and startOffset() may not be
    equal to termText.length(), as the term text may have been altered by a
    stemmer or some other filter. */
  public final int startOffset() { return startOffset; }

  /** Returns this Token's ending offset, one greater than the position of the
    last character corresponding to this token in the source text. */
  public final int endOffset() { return endOffset; }

  /** Returns this Token's lexical type.  Defaults to "word". */
  public final String type() { return type; }

}