Package org.xbill.DNS

Class Serial

java.lang.Object
org.xbill.DNS.Serial
public final class Serial extends Object
Helper functions for doing serial arithmetic. These should be used when setting/checking SOA serial numbers. SOA serial number arithmetic is defined in RFC 1982 and also referenced in RFC 2136.
Author:
Brian Wellington

  • Method Details

    • compare

      public static int compare(long serial1, long serial2)
      Compares two numbers using serial arithmetic. The numbers are assumed to be 32 bit unsigned integers stored in longs.
      Parameters:
      serial1 - The first integer
      serial2 - The second integer
      Returns:
      0 if the 2 numbers are equal, a positive number if serial1 is greater than serial2, and a negative number if serial2 is greater than serial1.
      Throws:
      IllegalArgumentException - serial1 or serial2 is out of range

    • increment

      public static long increment(long serial)
      Increments a serial number. The number is assumed to be a 32 bit unsigned integer stored in a long. This basically adds 1 and resets the value to 1 if it is 2^32. A zero value is explicitly forbidden as per * RFC 2136 section 4.2 and 7.11.
      Parameters:
      serial - The serial number
      Returns:
      The incremented serial number
      Throws:
      IllegalArgumentException - serial is out of range