public static function setIncludeFileCache($file)
    {
        if (null === $file) {
            self::$_includeFileCache = null;
            return;
        }

        if (!file_exists($file) && !file_exists(dirname($file))) {

            throw new Zend_Loader_PluginLoader_Exception('Specified file does not exist and/or directory does not exist (' . $file . ')');
        }
        if (file_exists($file) && !is_writable($file)) {

            throw new Zend_Loader_PluginLoader_Exception('Specified file is not writeable (' . $file . ')');
        }
        if (!file_exists($file) && file_exists(dirname($file)) && !is_writable(dirname($file))) {

            throw new Zend_Loader_PluginLoader_Exception('Specified file is not writeable (' . $file . ')');
        }

        self::$_includeFileCache = $file;
    }