Questions tagged [layers]

Layer (or abstraction level, or a layer of abstraction) is a way of hiding the implementation details of a particular set of functionality.

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2answers
61 views

Mantain same entity data in different layers

I'm trying to split the use of a business entity (e.g. a post) thought an application uses, trying to obtain a clean architecture So I will likely have: A class model, where the business logic lives ...
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135 views

What should I name this area of my architecture?

I am developing an architecture for a new MVC system. The legacy system has a layer it calls "facade", but it is not the classic GoF Facade. It is more like a service aggregator. It is used as a ...
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Unit Testing business logic layer that depends on data access layer [duplicate]

a discussion that rose among us devs: how to do unit test of Business logic layer that depends on data access layer. the two options are create test data in a test database (for example, H2). let the ...
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Where should objects be built from view-models in a layered architecture?

Having the following classes: Person.cs namespace Project.Domain { public class Person { public int Id { get; set; } public string Name { get; set; } public decimal ...
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1answer
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which layer must check if something(like account etc) exist in database

I am implementing a web api and i have crated three layers,data access layer,business layer and presentation layer. In data access layer I have a method which create a user.I use a transaction which ...
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Packaging of a web application code-base [closed]

Michael Nygard writes in Release It!: Have you ever checked in a commit that had bunch of new files like "Foo", "FooController", "FooFragment", "FooMapper", "FooDTO", and so on? That is evidence of ...
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289 views

Maintaining consistency with loosely coupled business and data layers

Take the following sequence of events: Business layer requests data x and y from data layer. Data layer returns version 1 of x and y. Business layer starts performing logic based on data x and y. ...
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2answers
119 views

Check permissions on top layer before going deeper

I'm building a four layer simple architecture with the following layers: Controller Actions and Events Repositories, that returns single entities or collections Models, where the SQL code resides ...
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Is ASP.NET Core Identity a leaky abstraction?

As far as I know, the DBContext or underlying persistance technology should be only contained inside the Data layer. Also, it feels very wrong to me to have identity package inside the user ...
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1answer
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Generic crud with jdbc api

I am used to programming java on the server side with ORM frameworks and using abstract classes for CRUD. But now I'm workign on a desktop project without ORM and just the good old JDBC API for ...
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Scalable QT/ C++ Architecture advice

I am working on software which supports different hardware device generations. With each software release all device generations are supported, what means that each device generation is also tested. ...
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1answer
63 views

Message passing interface between protocol layers

Let's imagine a custom network application having 3 protocol layers. Layer A is the top-level protocol and layer C is the lower level protocol. Each layer has its distinct functionalities. These ...
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0answers
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Understanding layered architecture: are these layers in a Nestjs application really decoupled?

I'm creating a new project usin Nestjs, which I'm really starting to like. I cannot figure out though, what the right way is for separating Business layer and Application layer. Following the ...
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346 views

Which layer do DDD Repositories belong to?

In his DDD book Evans promotes the idea of layered architecture, and in particular that the business logic should be confined to domain layer and separated from UI/persistence/other concerns. He also ...
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How is layer between MVC controller and back-end called?

I have ASP.NET MVC application with the following controller and action: public class AccountsController { public ActionResult Index() { var accounts = _accountsManager.GetAccounts();...
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1answer
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Questions about Direct access to data source from Services

Background: I'm trying to separate my concerns in the application architecture the best possible way. In a nutshell: The requests are parsed and go to an Action Action decides which service(s) to ...
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1answer
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Onion architecture vs 3 layered architecture

I see only benefits to the onion architecture over the 3 layered architecture where the BL had responsibility to call methods on DAL (or an interface of DAL) to do CRUD. The onion has better ...
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1answer
289 views

Two-level concepts

I find myself lately implementing the same concept twice, once at a low level and once at a higher level. Let me see if I can explain it... For example, given the notion of a database, I have one ...
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1answer
282 views

How to use ViewModels in a layered architecture?

I've got a Java application that is using a layered architecture, we have: presentation layer, business layer and data access layer. Our business layer uses the models to process the "requests". We ...
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1answer
506 views

DDD: Should create domain model for complex application layer?

I'm midway through Eric Evans' DDD book but don't think this question would be answered in the book. If an application has its own complicated concepts different from the underlying domain, can we ...
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1answer
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Communication between separated application parts

I have searched well before asking this question, and some of the questions look like what I need here, but none of the gave a clear answer to my question. I am writing a web application (in PHP if ...
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4answers
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Is it problematic to have a dependency between objects of the same layer in a layered software architecture?

Considering a medium-big software with an n-layer architecture and dependency injection, I am comfortable to say that an object belonging to a layer can depend on objects from lower layers but never ...
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3answers
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Java Interfaces in Layers pattern

I'm developing a Java software according to the object-oriented Layers architectural pattern. Every layer should be clearly separated from the rest, and provide a well-defined interface to use it's ...
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12answers
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How accurate is “Business logic should be in a service, not in a model”?

Situation Earlier this evening I gave an answer to a question on StackOverflow. The question: Editing of an existing object should be done in repository layer or in service? For example if ...
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3answers
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Business Logic Entities and Data Access Layer Entities

I am thinking on how to structure a project. I wonder if it is a good practice to use different entity classes between the BL and DAL in order to decouple these layers. I have worked on projects ...
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2answers
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How to correctly split a monolith and rely on the same domain

Context I'm developing a Spring Boot java application. Currently it is a monolith with the rest API and the front end (vaadin driven) in the same big project. Although this is very easy to develop ...
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288 views

How to properly decouple the service layer from the user interface layer, if the service layer needs to interact with the user?

In my program, I have a long-running function from which I would like to interact with the user for various reasons: Giving status updates ("Downloading file /foo/bar.png") Displaying warnings ("File ...
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1answer
52 views

Adding Security Layer for multiple services

My web application at the moment accepts REST requests and handled via some controllers, which calls corresponding services to perform the logic. Now I want to add in some security logic before ...
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N-Tier/Layered Architecture with MVC

Do N-Tier/Layered architecture really helpful with MVC? I have some projects here that use N-Tier architecture with MVC. The available layers are Entity Layer Data Layer Business Layer Presentation ...
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1answer
234 views

In an asp.net mvc application, can I use Entity layer as Model?

I am developing an asp.net mvc solution, which contains the three layers: Data Access Layer Business Layer Entity Layer Each layer is a project. I have developed the controllers and views, but no ...
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1answer
116 views

How should we approach layered-architectures that need large amounts of continuous, real-time, communication?

Background In much of the literature I've read online with respect to multi-layered architectures, many people describe how to create the simple application where: UI presents static model objects ...
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1answer
425 views

Consuming Rest, DAO or Service layer?

I feel like this is a dumb question but here it goes: If i'm consuming rest (getting data and transforming in POJO), does it sit in the DAO or Service layer? As for what i've researched I believe that ...
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1answer
48 views

Function for processing files: Business Layer, Service Layer, or anything else?

I read that Repositories should not refer to other repositories. I have a method ProcessFile that refers to multiple repositories, it parses a file, and inserts into many table models in different ...
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Clarification on the Onion architecture's Domain Service and Application Service

I am studying Onion Architeture but i got some doubts: All the samples (github) I found over internet are too simple, or are implemented under DDD (which I have not studied at the moment) so I can ...
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1answer
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Software layers and data mapping

Before I would ask my question, here is the context: I am working on one part of a relatively big software. In its simplest form there are 3 layers of the software lets call them lower layer, middle ...
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1answer
297 views

Where to convert int to enum in a 3-tier architecture?

I have a situation where a DB field is storing an enumeration value whose underlying type is int, so I'm getting back values like 0, 1, and 2, which should represent MyEnum.Foo, MyEnum.Bar, and MyEnum....
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0answers
339 views

Business Logic: 3-Layer-Architecture and Rich Domain Model

I have some questions about the "best" underlying architecture of software projects. I know, that there are different similiar posts but I'm really confused because it seems that everybody is telling ...
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1answer
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How is transactionality implemented in DDD applications?

I have been searching and reading recently about DDD and, so far, I think I understood its fundations. If I understood well, the architecture is similar to this: Database <--SQL--> DAO/ORM <...
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1answer
290 views

Why are the Android runtime and native libraries in the same layer?

Regarding the diagram in Android's website: https://developer.android.com/guide/platform Why did they put the Android Runtime category in the same layer as the native C/C++ libraries category. ...
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1answer
172 views

Data transfer between modules (layers)

I'm creating an application that is composed using different modules (core, course, grades, news). I'm using clean architecture for the different modules but I'm stuck trying to pass data from one ...
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2answers
897 views

Relaxed architecture DAL or anemic BLL?

Particularly for the sake of unit testing, I'm trying to implement an application with a layered architecture. I'm coding in C# and using ASP.NET Web API for the service layer. I'm aiming at a 3-layer ...
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3answers
194 views

Does Presentation Logic constrain design of Business layer?

We have an email plugin which encrypts a mail's attachments when the user sends an email and gives the mail's recipients permissions to decrypt the attachments. The recipient permissions are stored on ...
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Uncle Bob's clean architecture - An entity/model class for each layer?

BACKGROUND : I'm trying to use Uncle Bob's clean architecture in my android app. I studied many open source projects that are trying to show the right way to do it, and I found an interesting ...
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2answers
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When is a Use Case layer needed?

In his blog post The Clean Architecture Uncle Bob suggests a 4-layer architecture. I understand the separation between business rules, interfaces and infrastructure, but I wonder if/when it's ...
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6answers
12k views

Do stored procedures violate three-tier separation?

Some colleagues of mine have told me that having business logic in stored procedures in the database violates the three-tier separation architecture, since the database belongs to the data layer ...
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2answers
326 views

Disadvantageous of using entity framework layer directly into presentation layer (ASP.NET MVC) by skipping Service layer

In my company, We are planning to build more than one web application on a single Database. The proposed design of each of these apps are - ASP.NET MVC as Presentation layer, Restful API as service ...
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1answer
96 views

Decouple service complex query building from datastore

We have a very large search service (written in golang if it matters) that runs on top of ElasticSearch, receive requests, builds the correspondent query, and returns the results (with some post-...
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1answer
645 views

What layer does the presenter go in?

Whereas there seems to be a lot of information on the Internet about what the presenter both is and does, there doesn't seem to be a whole lot that specifically describes where to put it in a multi-...
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1answer
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Cross Entity Action Implementation

I have a domain layer, which my application architecture holds "sacred"; that is to say, the domain layer has no references to either data storage, or presentation concerns (vice-versa is allowed). I ...
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Does layered architecture still to be implemented inside all other architecture pattern like SOA and Microservices?

When we design the whole system we have few architecture pattern to select from. One of them is the layered architecture pattern, This pattern seems to be generic enough to fit in all other ...