static InetAddress getIPAddressFromNetworkInterface()

in tso-server/src/main/java/org/apache/omid/tso/NetworkInterfaceUtils.java [72:110]

• 29 lines of code
• 8 McCabe index (conditional complexity)

    static InetAddress getIPAddressFromNetworkInterface(String ifaceName)
            throws SocketException, UnknownHostException {

        NetworkInterface iface = NetworkInterface.getByName(ifaceName);
        if (iface == null) {
            throw new IllegalArgumentException(
                    "Network interface " + ifaceName + " not found");
        }

        InetAddress candidateAddress = null;
        Enumeration<InetAddress> inetAddrs = iface.getInetAddresses();
        while (inetAddrs.hasMoreElements()) {
            InetAddress inetAddr = inetAddrs.nextElement();
            if (!inetAddr.isLoopbackAddress()) {
                if (inetAddr.isSiteLocalAddress()) {
                    return inetAddr; // Return non-loopback site-local address
                } else if (candidateAddress == null) {
                    // Found non-loopback address, but not necessarily site-local
                    candidateAddress = inetAddr;
                }
            }
        }

        if (candidateAddress != null) {
            // Site-local address not found, but found other non-loopback addr
            // Server might have a non-site-local address assigned to its NIC
            // (or might be running IPv6 which deprecates "site-local" concept)
            return candidateAddress;
        }

        // At this point, we did not find a non-loopback address.
        // Fall back to returning whatever InetAddress.getLocalHost() returns
        InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
        if (jdkSuppliedAddress == null) {
            throw new UnknownHostException(
                    "InetAddress.getLocalHost() unexpectedly returned null.");
        }
        return jdkSuppliedAddress;
    }