protected String resolveUserSearchFilterPlaceHolders(String filter) {
    return filter
      .replace("{usernameAttribute}", usernameAttribute)
      .replace("{userObjectClass}", userObjectClass);
  }
Resolves known placeholders found within the given ldap user search ldap filter
@param filter
@return returns the filter with the resolved placeholders.
ambari-server/src/main/java/org/apache/ambari/server/security/authorization/LdapServerProperties.java