Source for gnu.javax.swing.text.html.parser.support.low.pattern

   1: /* pattern.java --
   2:    Copyright (C) 2005 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.javax.swing.text.html.parser.support.low;
  40: 
  41: 
  42: /**
  43:  * The simple pattern, consisting from the sequence of tokens that
  44:  * may have the unary modifier '?'. Choices and grouping
  45:  * are not required here.
  46:  * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
  47:  */
  48: public class pattern
  49: {
  50:   /**
  51:    * The nodes of this pattern.
  52:    */
  53:   public final node[] nodes;
  54: 
  55:   /**
  56:    * Create a pattern, containing the given list of nodes.
  57:    * @param a_nodes
  58:    */
  59:   public pattern(node[] a_nodes)
  60:   {
  61:     nodes = a_nodes;
  62:   }
  63: 
  64:   /**
  65:    * Checks if the pattern can match the tokens in this
  66:    * tokenizer. Does not change the state of tokenizer.
  67:    * @param stream The tokenizer to read data from
  68:    * @return True if the pattern sequence matches the
  69:    * beginning of the tokenizer content.
  70:    */
  71:   public boolean matches(ReaderTokenizer stream)
  72:   {
  73:     try
  74:       {
  75:         int pt = 0;
  76:         int pn = 0;
  77:         Token t;
  78:         node n;
  79: 
  80:         while (pn < nodes.length)
  81:           {
  82:             n = nodes [ pn ];
  83:             t = stream.getTokenAhead(pt);
  84: 
  85:             if (t.kind == n.kind)
  86:               {
  87:                 pn++;
  88:                 pt++;
  89:               }
  90:             else
  91:               {
  92:                 if (!n.optional)
  93:                   return false;
  94:                 else
  95:                   pn++;
  96:               }
  97:           }
  98:         return true;
  99:       }
 100:     catch (Exception ex)
 101:       {
 102:         throw new ParseException("Exception", ex);
 103:       }
 104:   }
 105: }