Kafka Round Robin

Main.java

static class Partition {
      int partition;
      int count;

      public Partition(int partition) {
          this.partition = partition;
          this.count = 0;
      }

      public int getCount() {
          return count;
      }

      @Override
      public String toString() {
          return String.format("{ p: %d, c: %d }", partition, count);
      }
  }

  public static void main(String[] args) {

      final int partitions = 20;
      final List<Integer> importedFileIds = List.of(
          72374,72373,72372,72371,72368,72369,72370,72367,72366,72365,72363,72364,72362,72361,72360,72359,72358,
          72357,72356,72355,72354,72353,72352,72351,72350,72349,72348,72347,72346,72345,72344,72343,72342,72341,72340,
          72339,72337,72338,72336,72335,72334,72333,72332,72331,72330,72329,72327,72328,72325,72326,72324,72323,72322,
          72319,72320,72321,72318,72317,72316,72315,72314,72313
      );

      Map<Integer, Partition> mapA = new HashMap<>();
      Map<Integer, Partition> mapB = new HashMap<>();
      for (final int importedFileId : importedFileIds) {

          final String importedFileStr = String.valueOf(importedFileId);
          int aPartition = calcPartition(importedFileStr.getBytes(), partitions);
          int bPartition = calcPartition(DigestUtils.md2(importedFileStr), partitions);

          if(!mapA.containsKey(aPartition)){
              mapA.put(aPartition, new Partition(aPartition));
          }
          if(!mapB.containsKey(bPartition)){
              mapB.put(bPartition, new Partition(bPartition));
          }

          mapA.get(aPartition).count++;
          mapB.get(bPartition).count++;

          System.out.printf(
              "importedFileId=%d, partition=%d, partition=%d %n", importedFileId, aPartition, bPartition
          );
      }

      final List<Partition> aPartitions = new ArrayList<>(mapA.values());
      final List<Partition> bPartitions = new ArrayList<>(mapB.values());
      Collections.sort(aPartitions, Comparator.comparingInt(Partition::getCount).reversed());
      Collections.sort(bPartitions, Comparator.comparingInt(Partition::getCount).reversed());

      System.out.println(aPartitions);
      System.out.println(bPartitions);
  }

  private static int calcPartition(byte[] key, int partitions) {
      return Utils.toPositive(Utils.murmur2(key)) % partitions;
  }