class IPv4 extends BasePacket {

    public static int toIPv4Address(String ipAddress) {
        if (ipAddress == null)
            throw new IllegalArgumentException("Specified IPv4 address must" +
                "contain 4 sets of numerical digits separated by periods");
        String[] octets = ipAddress.split("\\.");
        if (octets.length != 4)
            throw new IllegalArgumentException("Specified IPv4 address must" +
                "contain 4 sets of numerical digits separated by periods");

        int result = 0;
        for (int i = 0; i < 4; ++i) {
            int oct = Integer.valueOf(octets[i]);
            if (oct > 255 || oct < 0)
                throw new IllegalArgumentException("Octet values in specified" +
                        " IPv4 address must be 0 <= value <= 255");
            result |=  oct << ((3-i)*8);
        }
        return result;
    }

    public  IPv4();

}