throw new XAException("prepare called with unknown transaction");
throw new XAException(XAException.XAER_INVAL);
    public int prepare(Xid id) throws javax.transaction.xa.XAException {        if (log!=null) log.debug("prepare called: " + id);        isc_tr_handle committingTr = mcf.getTrHandleForXid(id);        if (committingTr == null) {            throw new XAException("prepare called with unknown transaction");        }        if (committingTr == currentTr) {            throw new XAException("prepare called with current xid");        }        mcf.prepare(id);        return XA_OK;    }