@Explain(displayName = "input format", explainLevels = { Level.USER, Level.DEFAULT, Level.EXTENDED })
  public String getInputFormat() {
    return inputFormat;
  }
DDL task description for ALTER TABLE ... SET FILEFORMAT ... commands.
ql/src/java/org/apache/hadoop/hive/ql/ddl/table/storage/set/fileformat/AlterTableSetFileFormatDesc.java