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.

Filter by
Sorted by
Tagged with
5
votes
1answer
270 views

Should I retrieve related entities from the parent entity or the service layer?

Let's say I have a three tier application structure, with Presentation, Service and Data layers. The data layer is managed by an ORM and has two models/entities, Show and Episode, with a one-to-many ...
2
votes
1answer
115 views

How to make associations security proof

When designing an application I usually stumble upon a problem I've never quite managed to handle properly. Suppose you have Products and Orders. Usually in my data-access layer I have repositories ...
4
votes
3answers
2k views

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 ...
0
votes
1answer
601 views

3-tier data access layer usage

As I understand in the 3-tier architecture, the presentation layer talks to business logic layer, which talks to data access layer. And, ideally, business layer knows nothing about presentation, and ...
0
votes
2answers
1k views

How To Design BLL in ASP.NET MVC

I'm trying to design a N-Tier Solution for my existing WebAPI project. I have a WebAPI project where, as of now, all the business logic are written in the controllers and the data validation are done ...
2
votes
2answers
2k views

Pattern for a method call outcome

Most often I need to call a service method from a controller, and based on the outcome, if there's an error show an appropriate error message depending on the error (or some other action, showing ...
4
votes
2answers
214 views

How do I know when to refactor global database query calls, and when to leave them alone?

I have the following global statement calls sprinkled throughout my PHP legacy codebase: $jobnumber = db_quick($sql); db_query($sql); That is, those function calls have been initialized in the ...
7
votes
1answer
2k views

Separate object used in business layer, data layer and presentation layer

I'm building an application that is responsible for reading data from files and displaying them in charts. The whole application is responsible for manipulating data from files, which means I have to ...
7
votes
1answer
3k views

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 <...
7
votes
2answers
743 views

What is a good reason for separating intelligence and dao layers in a microservice?

I am having a long-term debate with my architect about architecture choices. The entreprise where I work in is migrating from a monolithic architecture to a microservices one. The debate is located ...
0
votes
1answer
658 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-...
1
vote
0answers
105 views

JavaFX generating UI controlls from backend classes

I have a problem with my Software design. I want to generate UI controls from XML messages over the network. The XML messages contain simple information about a component and its properties for ...
3
votes
2answers
669 views

In which layer should sorting logic exist

I have an api with 3 layers 1.) The endpoint layer which exposes api endpoint handler functions. These generally call the business layer, aggregate the results to form an http response. 2.) The ...
6
votes
1answer
231 views

Globally interesting state in angularjs

I've created maybe five services like RoleService, AuthService, etc. Each of them has some state (e.g., RoleService.role, AuthService.isLoggedIn) affecting a lot of controllers and some other services ...
0
votes
1answer
8k views

Help me resolve this circular dependency?

This would be behind a spoiler tag if I could get the markdown to work. Sorry. As soon as I typed in "circular dependency", I got a ton of suggested results. Such as: How to handle “...
2
votes
3answers
891 views

Should Data Access Layer mirror my Database Configuration?

I am trying to decide how (or whether) my Data Access Layer should deal with existing security and integrity protections on the database. The architect in me says that separation of concerns is a ...
1
vote
2answers
158 views

How to abstract DB access and yet support flexible filtering?

I have a need to implement REST API which would support a complex filtering, so user would be able to make such requests: Products?$filter=Price le 3.5 or Price gt 200 The API server will use a ...
0
votes
0answers
471 views

How do I design a Service Layer in code?

I am currently rewriting one of my projects in Java and want to implement a service layer that will be used by different clients (CLI/GUI/Web) to communicate with my core application. For now it will ...
3
votes
1answer
296 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. ...
6
votes
4answers
4k views

What layer should contain interactions with external or remote resources which are not strictly data operations?

Assume an application with a layered architecture, i.e. presentation, business/domain/logic, data access: it makes sense to plug access to external APIs in at the data layer if what they do resembles ...
11
votes
1answer
7k views

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 ...
4
votes
2answers
993 views

Layered architectures and modular software

I have built a server-side Java application of about 10k lines of code and on a code review a colleague made me notice that when developing a new business feature , I have to touch several files. My ...
2
votes
1answer
104 views

Can I manage transactions in the UI

Do I need an "application/service" layer to manage transactions if the domain layer only services the UI? In other words, can't I just manage transactions in the UI when I have only one consumer of ...
2
votes
2answers
598 views

Domain object using DAO within a transaction

Is it considered good practice to start a transaction in the "service/application" layer, and then have objects in the domain model make DAO calls which participate in that transaction?
5
votes
3answers
1k views

How can you separate a monolith into domain-driven libraries without duplicating interfaces and still keep dependencies simple?

I'm working on a project with web services, and I've been structuring things where: The web service contains the business logic layer A library which handles the data access layer I've recently been ...
5
votes
2answers
906 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 ...
0
votes
1answer
140 views

Best practices for internationalization in layered applications

I'm building a new application in JSE for which I want to support internationalization. I've never built such an application. I'm looking for the best practices for internationalization. The ...
0
votes
1answer
153 views

Using static methods in layered architecture

In layered architecture does it matter where static methods go? Or is it the architect deciding this? For example can the DAL be static to cache records and perform smart data retrieval at the ...
5
votes
2answers
257 views

Save Two Different Domain Objects in One Service Call

Think that when one Branch saved, a Customer entity must created in n tier layered system architecture. All validation has already implemented in CustomerService. Should BranchService create ...
1
vote
1answer
766 views

Layer application and token authentication

Suppose we have an application with multiple layers in .Net: Domain layer (entities) Data access layer (entity framework) Business layer Web Services layer (Web Api) Presentation layer (MVC) Now I ...
2
votes
2answers
1k views

Integrating Logging Library into multilayer Object: What is a good structure?

I am integrating Serilog into and existing multilayer library that I've create. The previous logging technique I used was simply passing a string up the layers with events. I'd like to get away from ...
6
votes
1answer
298 views

MVC - Do I create 'joint' layers when dealing with multiple models?

I'm new to MVC and the different layers architecture and this is what I have currently: 2 models: User, Company 2 service layers: UserService, CompanyService 2 interfaces which abstract the ...
5
votes
1answer
212 views

Choosing between Dependency Inversion and Dependency “Delegation” to a third module

Suppose I have MasterPackage containing a Master class, and BlasterPackage containing Blaster class. Since Master needs a Blaster to work, the higher level MasterPackage depends directly on lower-...
45
votes
3answers
36k views

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 ...
4
votes
1answer
398 views

Testing of a layered software architecture

I am currently building an application with a layered architecture in C. Currently, I have built and tested the bottom layer, which is a networking module, providing functionality such as connecting/...
8
votes
3answers
827 views

Implementing a complexity hiding layer

As part of the dependencies that the project I'm working on has, we use several core services. These services, to which we can't make big changes, are a big mess. Depending on the method we invoke, we ...
1
vote
1answer
44 views

Can an outside component interact with lower layers directly in a strictly layered architecture

If we have a strictly layered architecture, can we allow outside components to interact directly with the lower layeres? More specifically: In my lower layers, I am providing a service, and in the ...
0
votes
2answers
535 views

In AngularJS - should $resource be used from controller or service?

All the documentation, examples and tutorials I've found on $resource were using it directly in the controller. So far I'm just using $http from services and those services are further used in the ...
3
votes
0answers
585 views

Refactoring to avoid circular references

I'm working on an ASP.NET MVC solution that has two projects, WebUI and DAL. WebUI references DAL. DAL has the repository and context, while WebUI contains Authentication and Authorization classes. ...
5
votes
2answers
2k views

Where should business logic go in a layered architecture?

First of all, i'm not talking about validation in the sense of the nullability or length of a field like in this and this questions where we can use isValid() methods in business classes or an ...
3
votes
3answers
238 views

Abstracton layer to control services access to denormalized db entity

Our db is optimized for minimum join count (partially denormalized). E.g. our User entity contains account data (nickname, facebook id, etc), user numerical statistics (total games played, total wins, ...
3
votes
1answer
699 views

OOP - How to refactor a “pyramid architecture”

Unbeknownst to me while I was building it, I built a "pyramid" architecture. I did not realize this until I laid it out in my new Visual Studio 2013 Layer Diagrammer. Each layer depends on the layer ...
2
votes
2answers
662 views

Do web applications use HTTP as a transport layer, or do they count as an integral part of the HTTP server?

Given an HTTP server (e.g. Apache, IIS) and a web application (user code running in the server using PHP, ASP.NET and the likes), which of those can decide which HTTP status code to return for any ...
5
votes
3answers
2k views

DDD, modularizing the application and domain layers without breaking the DIP

Quoting DDD theory: The application layer is thin in terms of domain logic - it merely coordinates the domain layer objects to perform the actual work. When it comes to modularization, and ...
3
votes
4answers
779 views

N-Layer architecture

I am attempting to structure my solution projects in such a manner as to improve testing, reuseability, separation of concerns and all that good stuff. Whilst I understand these concepts in theory, I ...
5
votes
6answers
3k views

Domain Model, validation, and pushing errors to the model

Looking into DDD and something I noticed is that business logic should be in the model, otherwise you just have property bags. That said how do you handle pieces of validation that require a trip to ...
0
votes
2answers
170 views

What layers reference each other in a multi layer design? [duplicate]

I'm creating a project and I'm having difficulty and contrasting opinions on how to do things when it comes down to separating layers. I'm not fully sure what layers should reference each other. I ...
2
votes
1answer
296 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 ...
1
vote
2answers
1k views

Where should the “not empty field” validation code be written on a 3-layer application?

When working with the 3-layer model, where should the validation code be placed? for: not empty fields, unchecked options, null values, wrong-written dates, etc. To keep total isolation between a ...
1
vote
3answers
4k views

Business Logic vs Presentation/View Logic

I often question myself of where to put the logic that organize the data to a view that is not necessarily a business logic in a 3-layered architecture (DAO, Business, View). I'll put an example to ...