private String getLdapUserSearchFilter(String userName) {
    return ldapServerProperties.get()
        .getUserSearchFilter(ldapConfigurationProvider.get().isLdapAlternateUserSearchEnabled() && AmbariLdapUtils.isUserPrincipalNameFormat(userName));
  }
Reloads LDAP Server properties from configuration

@return true if properties were reloaded
ambari-server/src/main/java/org/apache/ambari/server/security/authorization/AmbariLdapAuthenticationProvider.java