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

      switch (field) {
      case TABLE_NAME:
        return isSetTableName();
      case ROW:
        return isSetRow();
      case COLUMNS:
        return isSetColumns();
      case ATTRIBUTES:
        return isSetAttributes();
      }
      throw new java.lang.IllegalStateException();
    }
Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise
hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift/generated/Hbase.java