/** Set a language filter for literals. * * For example setting setLangFilter('en') will ignore all * non-english literals. * Set to null to disable language filtering of literals. * By default there is no language filter for literals. * * @param string $lang The language to accept (for example 'en') */ public static function setLangFilter($lang) { if (!is_string($lang) and $lang != null) { throw new InvalidArgumentException("\$lang should be a string or null"); } self::$_langFilter = $lang; }