@Override
    public int compareTo(Spec o) {
        int cmp = 0;
        if ((host != null) && (o.host != null)) {
            cmp = host.compareTo(o.host);
        } else if (host != null) {
            return -1;
        } else if (o.host != null) {
            return 1;
        }
        return (cmp == 0)
                ? Integer.compare(port, o.port)
                : cmp;

    }
Obtain a string representation of this address. The return
value from this method may be used to create a new Spec.

@return string representation of this address
jrt/src/com/yahoo/jrt/Spec.java