ArticleData::getFieldValue PHP Method

    public function getFieldValue($p_property, $p_forceFetchFromDatabase = false)
    {
        $dbColumnName = 'F' . $p_property;
        return parent::getProperty($dbColumnName, $p_forceFetchFromDatabase);
    }

 public function serializeToJson(JsonSerializationVisitor $visitor, $data, $type)
 {
     $articleData = new \ArticleData($data->type, $data->number, $data->languageId);
     if (count($articleData->getUserDefinedColumns()) == 0) {
         return null;
     }
     $fields = array();
     foreach ($articleData->getUserDefinedColumns() as $column) {
         $fields[$column->getPrintName()] = $articleData->getFieldValue($column->getPrintName());
     }
     $fields['show_on_front_page'] = $data->onFrontPage == "Y" ? 1 : 0;
     $fields['show_on_section_page'] = $data->onSection == "Y" ? 1 : 0;
     return $fields;
 }