org.argeo.api.uuid/src/org/argeo/api/uuid/MacAddressUuidFactory.java

   1 package org.argeo.api.uuid;
   2
   3 import java.net.InetAddress;
   4 import java.net.NetworkInterface;
   5 import java.net.SocketException;
   6 import java.net.UnknownHostException;
   7 import java.util.UUID;
   8
   9 /**
  10  * An {@link UUID} factory whose node id (for time based UUIDs) is the hardware
  11  * MAC address as specified in RFC4122.
  12  *
  13  * @see https://datatracker.ietf.org/doc/html/rfc4122.html#section-4.1.6
  14  */
  15 public class MacAddressUuidFactory extends ConcurrentUuidFactory {
  16         public final static UuidFactory DEFAULT = new MacAddressUuidFactory();
  17
  18         public MacAddressUuidFactory() {
  19                 this(0);
  20         }
  21
  22         public MacAddressUuidFactory(long initialClockRange) {
  23                 super(initialClockRange, localHardwareAddressAsNodeId());
  24         }
  25
  26         public static byte[] localHardwareAddressAsNodeId() {
  27                 InetAddress localHost;
  28                 try {
  29                         localHost = InetAddress.getLocalHost();
  30                         NetworkInterface nic = NetworkInterface.getByInetAddress(localHost);
  31                         return hardwareAddressToNodeId(nic);
  32                 } catch (UnknownHostException | SocketException e) {
  33                         throw new IllegalStateException(e);
  34                 }
  35
  36         }
  37
  38         public static byte[] hardwareAddressToNodeId(NetworkInterface nic) throws SocketException {
  39                 byte[] hardwareAddress = nic.getHardwareAddress();
  40                 final int length = 6;
  41                 byte[] arr = new byte[length];
  42                 for (int i = 0; i < length; i++) {
  43                         arr[i] = hardwareAddress[length - 1 - i];
  44                 }
  45                 return arr;
  46         }
  47
  48 }