public function toLdapFilter($alias = null)
{
if ($this->skipFilterForAlias($alias)) {
return '';
}
if ($this->getValueForQuery($alias) instanceof BaseOperator) {
return $this->getValueForQuery($alias)->toLdapFilter($alias);
}
return self::SEPARATOR_START . $this->getAttributeToQuery($alias) . $this->operatorSymbol . LdapUtilities::escapeValue($this->getValueForQuery($alias), null, LDAP_ESCAPE_FILTER) . self::SEPARATOR_END;
}