/**
  * Retrieve object using using composite pkey values.
  * @param      int $file_id
  * @param      int $dest_user_id
  * @param      PropelPDO $con
  * @return     DropboxPost
  */
 public static function retrieveByPK($file_id, $dest_user_id, PropelPDO $con = null)
 {
     $_instancePoolKey = serialize(array((string) $file_id, (string) $dest_user_id));
     if (null !== ($obj = DropboxPostPeer::getInstanceFromPool($_instancePoolKey))) {
         return $obj;
     }
     if ($con === null) {
         $con = Propel::getConnection(DropboxPostPeer::DATABASE_NAME, Propel::CONNECTION_READ);
     }
     $criteria = new Criteria(DropboxPostPeer::DATABASE_NAME);
     $criteria->add(DropboxPostPeer::FILE_ID, $file_id);
     $criteria->add(DropboxPostPeer::DEST_USER_ID, $dest_user_id);
     $v = DropboxPostPeer::doSelect($criteria, $con);
     return !empty($v) ? $v[0] : null;
 }