source: trunk/gli/src/org/greenstone/gatherer/util/HTMLStringTokenizer.java@ 4293

/**
 *#########################################################################
 *
 * A component of the Gatherer application, part of the Greenstone digital
 * library suite from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * <BR><BR>
 *
 * Author: John Thompson, Greenstone Digital Library, University of Waikato
 *
 * <BR><BR>
 *
 * Copyright (C) 1999 New Zealand Digital Library Project
 *
 * <BR><BR>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * <BR><BR>
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * <BR><BR>
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *########################################################################
 */

 




package org.greenstone.gatherer.util;
/**
 * Title:        The Gatherer<br>
 * Description:  The Gatherer: a tool for gathering and enriching digital collections.<br>
 * Copyright:    Copyright (c) 2001<br>
 * Company:      The University of Waikato<br>
 * @author John Thompson, Greenstone Digital Libraries
 * @version 2.1
 */
import java.util.Stack;
import org.greenstone.gatherer.util.Utility;
/** This class functions much like a <strong>StringTokenizer</strong> in that it tokenizes a long string into tokens, however this tokenizer cleverly notices HTML formatting tags. */
public class HTMLStringTokenizer {
     /** The current position in the source string. */
     private int pos = 0;
     /** The current token, usually created by the last nextToken call. */
     private String current = null;
     /** The previous token. */
     private String previous = null;
     /** The string to be tokenized, including any HTML markup. */
     private String source = null;
     /** Constructor.
      * @param source The source <strong>String</strong> to be tokenized.
      */
     public HTMLStringTokenizer(String source) {
          this.source = source;
          // Parse the first token.
          parseToken();
     }
     /** Determines if there are still tokens remaining unparsed in the source.
      * @return A <strong>boolean</strong> which is <i>true</i> if there are more tokens.
      */ 
     public boolean hasMoreTokens() {
          if(current != null && current.length() > 0) {
                return true;
          }
          return false;
     } 
     /** Determines if the tag currently being returned by sameToken is a tag.
      * @return A <strong>boolean</strong> indicating if the token is a tag.
      */
     public boolean isTag() {
          if(previous.startsWith("<") && previous.endsWith(">")) {
                return true;
          }
          return false;
     }
     /** Retrieves the next token. 
      * @return A <strong>String</strong> representing the token.
      */
     public String nextToken() {
          previous = current;
          // Get the next token.
          parseToken();
          // Return previous.
          return previous;
     }
     /** Repeats the result of the last <i>nextToken()</i>.
      * @return A <strong>String</strong> representing the token.
      */
     public String sameToken() {
          return previous;
     }
     /** Parses the next token and stores it in current.
      */
     private void parseToken() {
          boolean found = false;
          boolean tag = false;
          boolean text = false;
          // Reset current
          current = "";
          // Parse away
          dumpWhiteSpace();
          while(pos < source.length() && !found) {
                char c = (char)source.charAt(pos);
                if(!tag && !text) {
                     if(c == '<') {
                          tag = true;
                     }
                     else {
                          text = true;
                     }
                     current = current + c;
                }
                // Reading a tag. Watch only for '>'.
                else if(tag) {
                     if(c == '>') {
                          found = true;
                     }
                     current = current + c;
                }
                // Reading text. Watch for ' ' and '<'. Rollback '<'.
                else if(text) {
                     if(c == ' ') {
                          found = true;
                     }
                     else if(c == '<') {
                          found = true;
                          pos--;
                     }
                     else {
                          current = current + c;
                     }
                }
                pos++;
          }
     }
     /** Method to ignore whitespace in the source.
      */
     private void dumpWhiteSpace() {
          while(pos < source.length() && source.charAt(pos) == ' ') {
                pos++;
          }
     }

     static public void main(String args[]) {
          String init = "<HTML>Where material to be imported is found. Defaults to <i>GSDLHOME/collection/col_name/gimport</i></HTML>";
          ///ystem.err.println("Before: " + init);
          String result = Utility.formatHTMLWidth(init, 40);
          ///ystem.err.println("After: " + result);
     }
}