Method AppendValue

cpp/src/arrow/json/from_string.cc:804–838

Append a JSON value that must be a 2-long array, containing the type_id and value of the UnionArray's slot.

  // Append a JSON value that must be a 2-long array, containing the type_id
  // and value of the UnionArray's slot.
  Status AppendValue(const rj::Value& json_obj) override {
    if (json_obj.IsNull()) {
      return this->AppendNull();
    }
    if (!json_obj.IsArray()) {
      return JSONTypeError("array", json_obj.GetType());
    }
    if (json_obj.Size() != 2) {
      return Status::Invalid("Expected [type_id, value] pair, got array of size ",
                             json_obj.Size());
    }
    const auto& id_obj = json_obj[0];
    if (!id_obj.IsInt()) {
      return JSONTypeError("int", id_obj.GetType());
    }

    auto id = static_cast<int8_t>(id_obj.GetInt());
    auto child_num = type_id_to_child_num_[id];
    if (child_num == -1) {
      return Status::Invalid("type_id ", id, " not found in ", *type_);
    }

    auto child_converter = child_converters_[child_num];
    if (mode_ == UnionMode::SPARSE) {
      RETURN_NOT_OK(checked_cast<SparseUnionBuilder&>(*builder_).Append(id));
      for (auto&& other_converter : child_converters_) {
        if (other_converter != child_converter) {
          RETURN_NOT_OK(other_converter->AppendNull());
        }
      }
    } else {
      RETURN_NOT_OK(checked_cast<DenseUnionBuilder&>(*builder_).Append(id));
    }
    return child_converter->AppendValue(json_obj[1]);
  }

  std::shared_ptr<ArrayBuilder> builder() override { return builder_; }