Layered Architecture

The Layered Architecture pattern organizes an application into distinct layers, each with a specific role and responsibility. Layers are arranged hierarchically, with each layer building upon the services provided by the layer below. This separation promotes modularity, maintainability, and testability by reducing dependencies and making it easier to modify or replace individual components without affecting the entire system. A strict layered architecture dictates that a layer can only depend on the layer immediately below it.

Usage

Layered Architecture is frequently used in enterprise applications and large-scale software projects. It’s common in web applications (presentation, business logic, data access), desktop applications, and client-server systems. It’s particularly helpful when dealing with complex systems that require clear separation of concerns, making development, debugging, and future enhancements significantly easier. New technologies can be adopted more readily in a specific layer without cascading changes.

Examples

1. Model-View-Controller (MVC) Frameworks (e.g., Ruby on Rails, Django, Spring MVC): MVC is a specialization of layered architecture. The Model represents the data and business logic, the View handles the presentation layer, and the Controller manages user input and updates the model. These frameworks enforce a clear separation of concerns aligning with the principle of layering.

2. .NET Framework: The .NET Framework is architected in layers. The Presentation Layer (Windows Forms, WPF, ASP.NET), the Business Logic Layer (application services), the Data Access Layer (ADO.NET, Entity Framework), and the underlying Operating System/Hardware layers work in a hierarchical manner. Developers typically interact primarily with the top layers and can leverage the services of lower layers without needing detailed knowledge of their implementation.