Design Patterns and Best Practices in Java

Layered architecture with an example

To understand the layered architecture style further, let's take a look at the code and design example. Let's take a very simple requirement, where we need to get a list of employees from a database.

First of all, let's try to visualize the requirement in terms of layers by looking at this diagram:

We have created four layers, in this case. The presentation layer can be thought of as a simple HTML with JavaScript. You may want to use sophisticated frameworks, such as ReactJS or AngularJS, to keep things organized at the presentation layer, but in this example we have a simple presentation layer, where, ...