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

    switch (field) {
    case OPERATOR_ID:
      return isSetOperatorId();
    case OPERATOR_TYPE:
      return isSetOperatorType();
    case OPERATOR_ATTRIBUTES:
      return isSetOperatorAttributes();
    case OPERATOR_COUNTERS:
      return isSetOperatorCounters();
    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/Operator.java