public NetmaskIPAddressPermission(String mask) 
{
        Matcher matcher = MASK_VALIDATOR.matcher(mask);
        if (false == matcher.matches()) {
            throw new IllegalArgumentException("Mask " + mask + " does not match pattern " + MASK_VALIDATOR.pattern());
        }
        networkAddressBytes = new byte[4];
        for (int i = 0; i <  4; i++) {
            String group = matcher.group(i + 1);
            int value = Integer.parseInt(group);
            if (value <  0 || 255 <  value) {
                throw new IllegalArgumentException("byte #" + i + " is not valid.");
            }
            networkAddressBytes[i] = (byte) value;
        }
        netmaskBytes = new byte[4];
        String netmask = matcher.group(6);
        if (null != netmask) {
            int value = Integer.parseInt(netmask);
            int pos = value / 8;
            int shift = 8 - value % 8;
            for (int i = 0; i <  pos; i++) {
                netmaskBytes[i] = (byte) 0xff;
            }
            netmaskBytes[pos] = (byte) (0xff < <  shift);
        } else {
            for (int i = 0; i <  4; i++) {
                String group = matcher.group(i + 7);
                int value = Integer.parseInt(group);
                if (value <  0 || 255 <  value) {
                    throw new IllegalArgumentException("byte #" + i + " is not valid.");
                }
                netmaskBytes[i] = (byte) value;
            }
        }
}

 public static boolean canSupport(String mask) 
{
        Matcher matcher = MASK_VALIDATOR.matcher(mask);
        return matcher.matches();
}

 public boolean implies(InetAddress address) 
{
        if (false == address instanceof Inet4Address) {
            return false;
        }
        byte[] byteAddress = address.getAddress();
        for (int i = 0; i <  4; i++) {
            if ((netmaskBytes[i] & byteAddress[i]) != networkAddressBytes[i]) {
                return false;
            }
        }
        return true;
}