/**
  * get messages from folder
  *
  * @param string $_folderName
  * @return array
  */
 protected function _getMessages($_folderName = 'INBOX')
 {
     $folder = $this->_getFolder($_folderName);
     $filter = $this->_getMessageFilter($folder->getId());
     // update cache
     $folder = Felamimail_Controller_Cache_Message::getInstance()->updateCache($folder, 10, 1);
     $i = 0;
     while ($folder->cache_status != Felamimail_Model_Folder::CACHE_STATUS_COMPLETE && $i < 10) {
         $folder = Felamimail_Controller_Cache_Message::getInstance()->updateCache($folder, 10);
         $i++;
     }
     $result = $this->_json->searchMessages($filter, '');
     //print_r($result);
     return $result;
 }