public boolean isExpireByTimestampRange() {
      return timestampMillis != -1 && fromTimestampMillis != -1;
    }
Value object class, that stores the expire snapshot operation specific parameters
<ul>
  <li>Expire snapshot value: it should be a timestamp in milliseconds</li>
</ul>
ql/src/java/org/apache/hadoop/hive/ql/parse/AlterTableExecuteSpec.java