/**
  * @static
  * @return CvsClient|SvnClient
  */
 public static function getInstance()
 {
     $appConf = AccountManager::getInstance()->appConf;
     if (!isset(self::$instance)) {
         switch ($appConf['GLOBAL_CONFIGURATION']['vcs.type']) {
             case 'cvs':
                 require_once dirname(__FILE__) . '/CvsClient.php';
                 self::$instance = CvsClient::getInstance();
                 break;
             case 'svn':
                 require_once dirname(__FILE__) . '/SvnClient.php';
                 self::$instance = SvnClient::getInstance();
                 break;
         }
     }
     return self::$instance;
 }