protected function getCommonString($dn = null)
{
$dn = $dn ?: $this->dn;
$ldif = $this->addCommentsToString('');
$ldif .= $this->getLdifLine(Ldif::DIRECTIVE_DN, $dn);
$ldif = $this->addControlsToString($ldif);
$ldif .= $this->getLdifLine(Ldif::DIRECTIVE_CHANGETYPE, $this->changeType);
return $ldif;
}