Constants.java

package org.cdlib.xtf.textEngine;


/*
 * Copyright (c) 2004, Regents of the University of California
 * All rights reserved.
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 *
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 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
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 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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/**
 * Holds global constants for the XTF text system.
 *
 * @author Martin Haye
 */
public class Constants 
{
  /** Character guaranteed to be less than all special markers */
  public static final char MARKER_BASE = '\uE900';

  /** The character used to mark the start/end of a special bump token. */
  public static final char BUMP_MARKER = '\uEBBB';

  /** The special marker used to track the location of nodes within
   *  a chunk of text to be indexed.
   */
  public static final char NODE_MARKER = '\uE90D';

  /** The string used to represent a virtual word in a chunk of text. This
   *  string is chosen in such a way to be an unlikely combination of
   *  characters in typical western texts. Initially, the characters <b>qw</b>
   *  were selected as a mnemonic for a "quiet word".
   */
  public static final String VIRTUAL_WORD = "qw";

  // Special character glued to the start of the first token in a field (marks the 
  // start of the field.)
  //
  public static final char FIELD_START_MARKER = '\uEBEB';

  // Special character glued to the end of the last token in a field (marks the
  // end of the field.)
  //
  public static final char FIELD_END_MARKER = '\uEE1D';

  // Special character glued to XML element start/end tags
  public static final char ELEMENT_MARKER = '\uE111';

  // Special character glued to attribute name/value pairs within XML elements
  public static final char ATTRIBUTE_MARKER = '\uE112';
} // class XtfConstants