What's the difference between application layer and business logic layer?

Question

What's the difference between application layer and business logic layer? I kind of understand that business layer provides business specific services and application layer couples business services and provides services to the end user (Web Service, UI, etc). Am I right?

Answer 1

That sounds about correct.

The business layer implements the Domain Model in a boundary-technology-neutral way. In other words, it doesn't depend on any particular UI or service interface-related technology, such as web libraries or windowing APIs. You should be able to consume the business layer from any type of application - web, rich client, web service, etc.

The application layer bridges the gap between the business layer and the boundary technology.

Answer 2

To summarize:

• The application layer consists of those elements that are specific to this application. So that would contain the UI, back-end processing for the UI, and any bindings between the application and your business logic layer. In a perfect world, this layer would not contain any logic of the business domain.

• The business logic layer (BLL) contains logic specific to the business domain. Also, if you are going to create a separate BLL, this layer should contain logic that could be used by other applications as well as this one. For example, a set of web services exposing a well-defined API. This de-couples the BLL from your application and allows you the flexibility to build other applications on top of it in the future.

Answer 3

As I understand it the business layer is in charge of the business decisions AKA the logic involving the protocols of the client.

The application layer are the raw processes that have nothing to do with business decisions.

Answer 4

in classic layering in Business Layer we have:

-Business Rules -Security -User Activity Loging -Transaction Management ...

Functional Requierment + NonFunctional Requierment = Business Code

in DDD Functional Requierment Like Business Rules and Business Logic Stay in Domain Layer And NonFunctional Requiement Like Security and User Activity Loging Stay in Application Layer

Answer 5

I think of it as infrastructure. Depending on the application, it can contain the plumbing for configuration, reporting, the UI shell, etc.

Answer 6

In my head, the divide between Business and Application logic is this: Business logic manages data, Application logic manages users

—— from a comment here: https://www.bennadel.com/blog/2436-what-the-heck-is-business-logic-anyway.htm#comments_41200