In layered architecture, use cases are classes that encapsulate individual units of application logic. According to the reference, these classes are crucial components of an application's architecture because they contain logic that:
- Can be tested in isolation.
- Can be composed together to create more complex logic.
In essence, use cases represent specific interactions a user (or another system) has with the application. They detail the steps required to accomplish a particular goal.
Key Characteristics of Use Cases in Layered Architecture
Here's a breakdown of the key attributes of use cases in this context:
- Encapsulation of Logic: Use cases contain specific pieces of business logic related to a single function. This ensures that changes to one use case don't unintentionally affect others.
- Testability: Because each use case represents a distinct unit of functionality, it can be easily tested independently. This simplifies the testing process and improves the reliability of the application.
- Composability: Individual use cases can be combined to create more complex workflows or processes. This promotes code reuse and reduces redundancy.
- Layered Implementation: Use case classes typically reside in the business logic layer (also known as the service layer or application layer) of a layered architecture, separating them from the presentation layer (UI) and the data access layer.
Example Scenario
Imagine an e-commerce application. Some potential use cases could be:
CreateNewUser: Handles the creation of a new user account.AddToCart: Manages adding items to a user's shopping cart.ProcessPayment: Executes the payment processing logic.GenerateSalesReport: Generates sales reports based on specific criteria.
Each of these use cases would encapsulate the necessary logic to perform its task. ProcessPayment, for example, would contain the steps for validating payment information, communicating with a payment gateway, and updating order status.
Benefits of Using Use Cases
Here are some benefits of using use cases in a layered architecture:
- Improved Maintainability: Changes to business logic are isolated to specific use case classes, reducing the risk of unintended side effects.
- Enhanced Reusability: Use cases can be reused in different parts of the application, promoting consistency and reducing development effort.
- Simplified Testing: Independent testability of use cases leads to more reliable and robust applications.
- Clearer Architecture: Use cases provide a clear separation of concerns, making the application easier to understand and maintain.
