private static Integer parseHourToTransformHour(String hourStr) {
    final OffsetDateTime epoch = Instant.ofEpochSecond(0).atOffset(ZoneOffset.UTC);
    String[] parts = hourStr.split("-", -1);
    Preconditions.checkState(parts.length == 4);
    int year = Integer.parseInt(parts[0]);
    int month = Integer.parseInt(parts[1]);
    int day = Integer.parseInt(parts[2]);
    int hour = Integer.parseInt(parts[3]);
    OffsetDateTime datetime = OffsetDateTime.of(LocalDateTime.of(year, month, day, hour, /* minute=*/0),
        ZoneOffset.UTC);
    return (int) ChronoUnit.HOURS.between(epoch, datetime);
  }
In the partition path hours are represented as year-month-day-hour, e.g.
1970-01-01-01. We need to convert it to a single integer which represents the hours
from '1970-01-01 00:00:00'.
iceberg/iceberg-handler/src/main/java/org/apache/iceberg/mr/hive/HiveIcebergFilterFactory.java