find country code by ip using ip ranges implemented by TreeMap

IPToCountryCodeTest.java

   /**
    * This utility provides methods to either convert an IPv4 address to its long format or a 32bit dotted format.
    *
    * @author Aion
    *   Created on 22/11/12
    */
    public static class IPv4 {

        /**
         * Returns the long format of the provided IP address.
         *
         * @param ipAddress the IP address
         * @return the long format of <code>ipAddress</code>
         * @throws IllegalArgumentException if <code>ipAddress</code> is invalid
         */
        public static long toLong(String ipAddress) {
            if (ipAddress == null || ipAddress.isEmpty()) {
                throw new IllegalArgumentException("ip address cannot be null or empty");
            }
            String[] octets = ipAddress.split(java.util.regex.Pattern.quote("."));
            if (octets.length != 4) {
                throw new IllegalArgumentException("invalid ip address");
            }
            long ip = 0;
            for (int i = 3; i >= 0; i--) {
                long octet = Long.parseLong(octets[3 - i]);
                if (octet > 255 || octet < 0) {
                    throw new IllegalArgumentException("invalid ip address");
                }
                ip |= octet << (i * 8);
            }
            return ip;
        }

        /**
         * Returns the 32bit dotted format of the provided long ip.
         *
         * @param ip the long ip
         * @return the 32bit dotted format of <code>ip</code>
         * @throws IllegalArgumentException if <code>ip</code> is invalid
         */
        public static String toString(long ip) {
            // if ip is bigger than 255.255.255.255 or smaller than 0.0.0.0
            if (ip > 4294967295l || ip < 0) {
                throw new IllegalArgumentException("invalid ip");
            }
            StringBuilder ipAddress = new StringBuilder();
            for (int i = 3; i >= 0; i--) {
                int shift = i * 8;
                ipAddress.append((ip & (0xff << shift)) >> shift);
                if (i > 0) {
                    ipAddress.append(".");
                }
            }
            return ipAddress.toString();
        }

    }

    public class IP2CountyCodeMap {
        private final TreeMap<Long, CountryCodeEntry> ipMap = new TreeMap<Long, CountryCodeEntry>();

        public void addIpRange(String startIp, String endIp, String countryCode) {
            addIpRange(IPv4.toLong(startIp), IPv4.toLong(endIp), countryCode);

        }
        public void addIpRange(long startIp, long endIp, String countryCode) {
            ipMap.put(startIp, new CountryCodeEntry(endIp, countryCode));
        }

        public String getCountryCode(String ip) {
            return getCountryCode(IPv4.toLong(ip));
        }

        public String getCountryCode(long ip) {
            Map.Entry<Long, CountryCodeEntry> entry = ipMap.floorEntry(ip);
            if (entry != null && ip <= entry.getValue().endIpAddress) {
                return entry.getValue().countryCode;
            }

            return null;
        }
    }

    public class CountryCodeEntry {
        public final long endIpAddress;
        public final String countryCode;
        public CountryCodeEntry (long endIpAddress, String countryCode) {
            this.endIpAddress = endIpAddress;
            this.countryCode = countryCode;
        }
    }

    @Test
    public void findCountryCodeByIP() throws Exception {

        IP2CountyCodeMap IP2CountyCodeMap = new IP2CountyCodeMap();
        IP2CountyCodeMap.addIpRange("192.168.0.0", "192.168.100.0", "aaa");
        IP2CountyCodeMap.addIpRange("192.168.100.1", "192.168.200.0", "bbb");
        IP2CountyCodeMap.addIpRange("192.168.200.1", "192.168.240.0", "ccc");

        Assert.assertEquals("aaa", IP2CountyCodeMap.getCountryCode("192.168.9.9"));
        Assert.assertEquals("bbb", IP2CountyCodeMap.getCountryCode("192.168.100.9"));
        Assert.assertEquals("ccc", IP2CountyCodeMap.getCountryCode("192.168.200.9"));
    }