Method Make

cpp/src/arrow/type.cc:1051–1066

}

Result<std::shared_ptr<DataType>> MapType::Make(std::shared_ptr<Field> value_field,
                                                bool keys_sorted) {
  const auto& value_type = *value_field->type();
  if (value_field->nullable() || value_type.id() != Type::STRUCT) {
    return Status::TypeError("Map entry field should be non-nullable struct");
  }
  const auto& struct_type = checked_cast<const StructType&>(value_type);
  if (struct_type.num_fields() != 2) {
    return Status::TypeError("Map entry field should have two children (got ",
                             struct_type.num_fields(), ")");
  }
  if (struct_type.field(0)->nullable()) {
    return Status::TypeError("Map key field should be non-nullable");
  }
  return std::make_shared<MapType>(std::move(value_field), keys_sorted);
}

std::string MapType::ToString(bool show_metadata) const {
  std::stringstream s;