@Explain(displayName = "number of buckets", explainLevels = { Level.USER, Level.DEFAULT, Level.EXTENDED })
  public int getNumberOfBuckets() {
    return numberOfBuckets;
  }
DDL task description for ALTER TABLE ... INTO ... BUCKETS commands.
ql/src/java/org/apache/hadoop/hive/ql/ddl/table/storage/cluster/AlterTableIntoBucketsDesc.java