@HiveDecimalVersionV1
  public long longValueExact() {
    if (!isLong()) {
      throw new ArithmeticException();
    }
    return fastLongValueClip();
  }
Return the long value of a decimal.
<p>
This method will return a corrupted value unless isLong() is true.
storage-api/src/java/org/apache/hadoop/hive/common/type/HiveDecimal.java