@org.apache.thrift.annotation.Nullable
  public java.lang.Object getFieldValue(_Fields field) {
    switch (field) {
    case START_ROW:
      return getStartRow();

    case STOP_ROW:
      return getStopRow();

    case COLUMNS:
      return getColumns();

    case CACHING:
      return getCaching();

    case MAX_VERSIONS:
      return getMaxVersions();

    case TIME_RANGE:
      return getTimeRange();

    case FILTER_STRING:
      return getFilterString();

    case BATCH_SIZE:
      return getBatchSize();

    case ATTRIBUTES:
      return getAttributes();

    case AUTHORIZATIONS:
      return getAuthorizations();

    case REVERSED:
      return isReversed();

    case CACHE_BLOCKS:
      return isCacheBlocks();

    case COL_FAM_TIME_RANGE_MAP:
      return getColFamTimeRangeMap();

    case READ_TYPE:
      return getReadType();

    case LIMIT:
      return getLimit();

    case CONSISTENCY:
      return getConsistency();

    case TARGET_REPLICA_ID:
      return getTargetReplicaId();

    case FILTER_BYTES:
      return getFilterBytes();

    }
    throw new java.lang.IllegalStateException();
  }
Returns true if field filterBytes is set (has been assigned a value) and false otherwise
hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/generated/TScan.java