public boolean isSet(_Fields field) {
    if (field == null) {
      throw new java.lang.IllegalArgumentException();
    }

    switch (field) {
    case STAGE_ID:
      return isSetStageId();
    case STAGE_TYPE:
      return isSetStageType();
    case STAGE_ATTRIBUTES:
      return isSetStageAttributes();
    case STAGE_COUNTERS:
      return isSetStageCounters();
    case TASK_LIST:
      return isSetTaskList();
    case DONE:
      return isSetDone();
    case STARTED:
      return isSetStarted();
    }
    throw new java.lang.IllegalStateException();
  }
Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise
ql/src/gen/thrift/gen-javabean/org/apache/hadoop/hive/ql/plan/api/Stage.java