我相信我遇到了和原始图表中导航网关“错位”相同的问题，并正在寻找解决方法。
再次，Cockburn的解释可能因为不寻常的六边形图像而有些难以理解，但它更加精确，因为它不试图包含所有内容，而是专注于依赖性基础知识。
网关接口必须位于用例层，并在接口适配器层中实现，以确保依赖规则。
Interface Adapters Layer || Use Cases Layer
||
+-----------------+ || <implements> +-------------+ <uses> +---------+
|JDBCEntityGateway| --------++--------------> +EntityGateway| <------ | UseCase |
+-----------------+ || +-------------+ +---------+
||
这个模式可以应用于每个架构边界。更高级别的层次定义一个接口，告诉它需要什么而不是如何完成任务。较低级别的层次实现该接口，从而定义其完成方式。也许这就是为什么该层被命名为接口适配器。由此产生的结果是，通过提供另一种实现，您可以改变某些事情的完成方式。现在你可能会认识到这是开闭原则。
但请记住，接口应该是用例需求的稳定抽象。不要在接口中加入特定于实现的内容，例如，如果您像这样指定查找方法List<Eintity> find(String where)，因为where字符串是一个细节，可能是SQL或JPQL字符串的一部分。您应该引入一个EntityCriteria，以一种实现无关的方式描述选择标准。
import 'package:entities/entities.dart';
/// [GetDogsResourceUseCase] is a class with functions that have prominent
/// positions within the architecture, and they will have names that clearly
/// describe their function.
/// From the [GetDogsResourceUseCase], it is impossible to tell whether the
/// application is delivered on the web, on a thick client, or a console,
/// or is a pure service.
abstract class GetDogsResourceUseCase {
const GetDogsResourceUseCase();
Stream<Resource<List<Dog>>> callAsStream([Params params]);
Future<Resource<List<Dog>>> callAsFuture([Params params]);
}
import 'package:dogs_app_interface_adapters/dogs_app_interface_adapters.dart';
import 'package:dogs_app_use_cases/dogs_app_use_cases.dart';
import 'package:entities/entities.dart';
import 'package:injectable/injectable.dart';
/// A [GetDogsResourceUseCaseAdapter] specifies the [Params]
/// to be provided by the user, the [Resource] to be returned to the user, and
/// the processing steps involved in producing that output [Resource].
@Injectable(as: GetDogsResourceUseCase)
class GetDogsResourceUseCaseAdapter implements GetDogsResourceUseCase {
const GetDogsResourceUseCaseAdapter(this._dogsGateway);
final DogsGateway _dogsGateway;
@override
Stream<Resource<List<Dog>>> callAsStream([
Params input = const Params(),
]) {
//TODO: implement
// step 1
//_paramsGateway.getSavedDogsAsStream,
// step 2
//_dogsGateway.requestDogs,
// step 3
//_dogsGateway.saveDogs,
}
@override
Future<Resource<List<Dog>>> callAsFuture([
Params input = const Params(),
]) {
//TODO: implement
// step 1
//_dogsGateway.getSavedDogsAsFuture,
// step 2
//_dogsGateway.requestDogs,
// step 3
//_dogsGateway.saveDogs,
}
网关：
import 'package:entities/entities.dart';
abstract class DogsGateway {
Future<List<Dog>> requestDogs([
Params params = const Params(),
]);
Stream<List<Dog>> getSavedDogsAsStream([
Params params = const Params(),
]);
Future<List<Dog>> getSavedDogsAsFuture([
Params params = const Params(),
]);
Future<void> saveDogs(List<Dog> dogs);
}
框架和驱动程序
网关实现：
@Injectable(as: DogsGateway)
class DogsGatewayImpl implements DogsGateway {
const DogsGatewayImpl(this._restClient, this._dogsDao);
final RestClient _restClient;
final DogsDao _dogsDao;
@override
Stream<List<Dog>> getSavedDogsAsStream([
Params params = const Params(),
]) {
//TODO: implement
//_dogsDao.streamDogs
}
@override
Future<List<Dog>> getSavedDogsAsFuture([
Params params = const Params(),
]) {
//TODO: implement
//_dogsDao.getDogs
}
@override
Future<List<Dog>> requestDogs([
Params params = const Params(),
]) {
//TODO: implement
//_getDogsResponse(params)
}
@override
Future<void> saveDogs(List<Dog> dogs) {
// TODO: Save remote dogs in a local database
//_dogsDao.updateDogs
}
