* Check if we can connect to the server, throws appropriate exception otherwise
*/
void checkCanConnectServer() throws ServiceException {
if (isOffline()) {
LOGGER.debug("Offline mode"); //$NON-NLS-1$
throw new OfflineException();
}
if (!(_lastFailedTime < 0 || _lastFailedTime+DELAY_BEFORE_RETRY < System.currentTimeMillis())) {
LOGGER.info("prevent connection to server.(delay before retry not reached)"); //$NON-NLS-1$
throw new ServiceNotAvailableException(Messages.getString("services.error.serverdown")); //$NON-NLS-1$
}