What is Layered Architecture?
Layered architecture is an architectural pattern or software design principle used to create highly cohesive and loosely coupled software applications. It provides for the organisation of software in horizontal and vertical layers which typically consists of presentation, data access and business logic layers. Layered architecture is well-defined and establishes a logical flow of information from the user interface to the data layer. It ensures that the modules and components of the system fit together correctly and communicate adequately.
Benefits of Layered Architecture
Layered architecture provides a number of advantages to software developers, including the ability to easily modify the system without breaking it down; changes can be applied to downstream elements without needing to change upstream components. This is how specialisation and invariants are achieved, allowing different areas of the system to evolve independently. Modular architecture also makes the code easier to maintain and test as it is simpler to isolate technical or behavioural issues and create coverage metrics.
In addition to this, layered architecture promotes code reuse when components are written within a standardised language, as code can be easily recycled from other applications. Furthermore, it helps to decrease complexity by abstracting away business logic and enabling the user interface to ignore implementation details.
Layered Architecture Applications in Development
Layered architecture lends itself to the development of distributed applications that have user interfaces, business logic, and databases. In these multi-tiered applications, each layer has a distinct responsibility and communicates with adjacent layers through well-defined interfaces.
For example, in an application with a graphical user interface (GUI), information is transmitted from the user to the underlying business logic through abstract data constructs such as elements like lists, tables, or forms. These data constructs then become the data passed between the layers, and the business logic will contain the routines to manipulate this data and interact with the database or other external components.
Layered architecture is also used in service-oriented architecture, where applications are built by discovering and using service interfaces available to the application.
Drawbacks of Layered Architecture
Although layered architecture provides a great level of modularity, there are some problems associated with it. One of the main drawbacks of layered architecture is its reliance on abstract data types. This means that in order for an application to communicate and share data, it must first agree on the format and the meaning of the data and the messages that pass between the layers. This can be a time-consuming process, as the messages and data must be thoroughly documented and available for the entire application.
In addition to this, layered architecture can also lead to complexity, as components in different layers must be interfaced. Since there are a lot of components and layers, they must be managed constantly to ensure that all components remain consistent.
Benefits and Drawbacks of Performance
Layered architecture can have both positive and negative results on performance. On one hand, by separating the user interface layer from the business logic and/or the data access layer, performance can be increased by reducing the number of calls to and from the backend. On the other hand, this separation can also add an additional layer of latency, which can compromise the performance of the system.
When it comes to the user interface, layered architecture helps to make the design more streamlined and the navigation faster. By separating the user interface, the data layer and the business layer, it is easier for developers to work on and demonstrate different design options.
Summary of Layered Architecture
Layered architecture is an architectural pattern or software design principle used to create highly cohesive and loosely coupled software applications. It provides for the organisation of software in horizontal and vertical layers which typically consists of presentation, data access, and business logic layers.
Layered architecture provides a number of advantages to software developers, including the ability to easily modify the system without breaking it down and enables specialisation and invariants to be achieved. It also makes code easier to maintain and test and promotes code reuse. Layered architecture is commonly used in the development of distributed applications and service-oriented architecture, but can also lead to complexity and have both positive and negative effects on performance.
