public void setFieldValue(_Fields field, @org.apache.thrift.annotation.Nullable java.lang.Object value) {
    switch (field) {
    case NUM_TXNS:
      if (value == null) {
        unsetNum_txns();
      } else {
        setNum_txns((java.lang.Integer)value);
      }
      break;

    case USER:
      if (value == null) {
        unsetUser();
      } else {
        setUser((java.lang.String)value);
      }
      break;

    case HOSTNAME:
      if (value == null) {
        unsetHostname();
      } else {
        setHostname((java.lang.String)value);
      }
      break;

    case AGENT_INFO:
      if (value == null) {
        unsetAgentInfo();
      } else {
        setAgentInfo((java.lang.String)value);
      }
      break;

    case REPL_POLICY:
      if (value == null) {
        unsetReplPolicy();
      } else {
        setReplPolicy((java.lang.String)value);
      }
      break;

    case REPL_SRC_TXN_IDS:
      if (value == null) {
        unsetReplSrcTxnIds();
      } else {
        setReplSrcTxnIds((java.util.List<java.lang.Long>)value);
      }
      break;

    case TXN_TYPE:
      if (value == null) {
        unsetTxn_type();
      } else {
        setTxn_type((TxnType)value);
      }
      break;

    }
  }
Returns true if field txn_type is set (has been assigned a value) and false otherwise
standalone-metastore/metastore-common/src/gen/thrift/gen-javabean/org/apache/hadoop/hive/metastore/api/OpenTxnRequest.java