static public function purgeUserCacheByUserId( $userId )
    {
        if ( eZINI::instance()->variable( 'RoleSettings', 'EnableCaching' ) === 'true' )
        {
            $cacheFilePath = eZUser::getCacheDir( $userId ). "/user-data-{$userId}.cache.php" ;
            eZClusterFileHandler::instance()->fileDelete( $cacheFilePath );
        }
    }