/**
  * clear cache
  *
  * @return void
  */
 protected function _clearCache()
 {
     // setup cache (via tinebase because it is disabled in setup by default)
     Tinebase_Core::setupCache(TRUE);
     Setup_Core::getLogger()->info(__METHOD__ . '::' . __LINE__ . ' Clearing cache ...');
     // clear cache
     $cache = Setup_Core::getCache()->clean(Zend_Cache::CLEANING_MODE_ALL);
     // deactivate cache again
     Tinebase_Core::setupCache(FALSE);
 }