code: public boolean hasNextToken() {
      if (this.nextToken == null) {
        try {
          this.nextToken = this.jlexer.yylex();
        } catch (final IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
        }
      }
      return this.nextToken != null;
    }
docs: Check if the next token provided by yylex() is null.
  
  @return true or false