All the sources codes "But why ?"page 39

short clientTypeId = short.Parse("2");

// . . .
	return $this->boolean((bool)$data);
}
	
/**
 * Translates between PHP boolean values and Database (faked) boolean values
 *
 * @param mixed $data Value to be translated
 * @return mixed Converted boolean value
 * @access public
 */
	function boolean($data) {
		if ($data === true || $data === false) {
			if ($data === true) {
				return "true";
			}
			return "false";
		} else {
			return !empty($data);
		}
	}

if(zftDTOList == null || (zftDTOList != null && zftDTOList.size() < 1))
{
//....
}