Clean Architecture with multimodules written in Java and the web layer is build with the help of Spring.
Clean Architecture main directory contains all the modules which realize the working of application.
webapplication, inmemorydb and applicationdi modules are part of the Framework and drivers layer.
interfaceadpters module is part of Interface Adapters layer.
usecases module is part of Application Business Rules layer.
entities module is part of Enterprise Business Rules layer.
Dependency direction of the modules from the outermost to the center.
Outside layer depends on the layer below it.
The inner layer has no dependency on the layer above and no information for any class or method from it.
Changes on the outer layer should not cause changes to the inner layer it.
applicationdi module uses inmemorydb, usecases, interfaceadpters modules to inject the dependencies that are needed in this application.
Webapplication module is part of framework and drivers layer. Framework and drivers layer is the outermost layer.
webapplication module depends on the layer below it: interface adapters.
webapplication module uses spring framework.
The endpoints which are in this layer with help of spring annotations build together the entrypoints for the input.
Example schema of one case of Gauss elimination for linear equations with Clean Architecture.
This schema shows the interaction between weabapplication module and interfaceadapters module.
Class diagram shows the dependencies of GetGaussSolutionsEndpoint.class in webapplication module from the interfaceadapters module.
GetGaussSolutionsEndpoint.class uses two interfaces from interfaceadapters module to cross the boundary between layers.
GetGaussSolutionsControllerInputBoundary interface that is implemented by GetGaussSolutionsController class which gets the input (GetSolutionsControllerRequest).
GetGaussSolutionsController will send the input to the usecase layer to be processed, later explained in details.
The second interface GaussSolutionsPresenterOutputBoundary interface that is implemented by GaussSolutionsPresenter class
will be used by GetGaussSolutionsEndpoint.class to get the output (GaussSolutionsViewModel) and present to the web.
GaussSolutionsPresenter receive the processed output from usecase layer, later explained in details.
interfaceadapters module depends on the the layer below it concretely on usecases module. The schema below shows the interaction between interfaceadapters module and usecases.
Class diagram below shows the dependencies of classes in interfaceadapters module on the layer above in usecase module. Both the presenter and controller communicate with the usecase using the interfaces,
which helps to pass the boundary and don't break the dependency rules.
GetGaussSolutionsController.class in the interfaceadapters module uses the interface GetGaussSolutionsInputBoundary which is in the usecase module to send the request to the GetGaussSolutions.class.
GetGaussSolutions.class is the usecase of getting the gauss solutions.
GetGaussSolutions.class implements GetGaussSolutionsInputBoundary interface and get the requset from GetGaussSolutionsController.class.
On the same time GetGaussSolutions.class uses GaussSolutionsOutputBoundary interface.
GaussSolutionsOutputBoundary interface is implemented by GaussSolutionsPresenter.class in interfaceadapters module.
GetGaussSolutions.class presents the response to GaussSolutionsPresenter.class with the help of GaussSolutionsOutputBoundary interface.
In this way the direction of the dependency stays from interfaceadapters layer to usecase layer
without breaking any depency rules and without creating any dependency from the higher level module to the lower level module.
And finally the usecases module schema which shows the only dependency to entities module.
Class diagram of the usecase.
Api calls
Api call to solve linear equations with gausssolver
POST
http://localhost:8080/gausssolver-service/api/v1/gausssolver
body
{
"a": [[2.0,4.0],[5.0, -6.0]],
"b": [8.0,4.0]
}
Response of the call:
{
"solution": [
2.0,
1.0
]
}
Api call to get the solutions
GET
http://localhost:8080/gausssolver-service/api/v1/gausssolver
Response of the call:
{
"solutionsData": [
{
"id": 1,
"date": "2020-11-11",
"document": "{"a":[[2.0,4.0],[5.0,-6.0]],"b":[8.0,4.0]}",
"result": "[2.0,1.0]"
}
]
}
Swagger documentation
http://localhost:8080/gausssolver-service/swagger-ui.html#/gausssolver
[https://blog.cleancoder.com/uncle-bob/2012/08/13/the-clean-architecture.html)
[https://github.com/grant-burgess/clean-architecture-example-java-spring-boot)