@Override
 public void reset() throws IOException {
   super.reset();
   tokenIterator = tokens.iterator();
 }
 /**
  * Creates a new ListBasedTokenStream which uses the given tokens as its token source.
  *
  * @param tokens Source of tokens to be used
  */
 ListBasedTokenStream(List<AttributeSource> tokens) {
   this.tokens = tokens;
   tokenIterator = tokens.iterator();
 }