private static function _isActive()
 {
     if (self::$_isActive == -1) {
         // This override is part of the cloudcache module, so the cloudcache.php file exists
         require_once dirname(__FILE__) . '/../../../modules/cloudcache/cloudcache.php';
         $module = new CloudCache();
         self::$_isActive = $module->active;
     }
     return self::$_isActive && Configuration::get('CLOUDCACHE_API_ACTIVE');
 }