/**
  * @static
  * @return string "windows" or "unix"
  */
 public static function getSystemEnvironment()
 {
     if (self::$systemEnvironment == null) {
         if (stripos(php_uname("s"), "windows") !== false) {
             self::$systemEnvironment = 'windows';
         } else {
             self::$systemEnvironment = 'unix';
         }
     }
     return self::$systemEnvironment;
 }