public function __construct($startDelimiter, $endDelimiter)
 {
     parent::__construct();
     $this->startDelimiter = $startDelimiter;
     $this->endDelimiter = $endDelimiter;
 }
 public function __construct($expressionLanguage = NULL) {
     parent::__construct();
     $this->expressionLanguageHandler = FormulaExpressionLanguageFactory::getInstance()->getHandler($expressionLanguage);
 }