public function getDisplayValue()
    {
        $values = array();

        if (count($this->groupFields)) {
            $i = 0;
            foreach ($this->groupFields as $key => $group) {
                $fields = $group['fields'];
                $item = array();
                foreach ($fields as $field) {
                    $item[$field->getFieldName()] = $field->getDisplayValue();
                }
                $item['id'] = $key;
                $values[$i] = $item;
                ++$i;
            }
        }

        return $values;
    }