else { if(log.isErrorEnabled()) log.error("index " + index + " is out of bounds"); return 0; }
    public long highSeqnoAt(Address sender) {        long ret=-1;        int index;        if(sender == null) return ret;        index=getIndex(sender);        if(index == -1)            return ret;        else            return high_seqnos[index];    }