Salesforce Best Practice: Using Selector Classes

In Salesforce Apex development, adhering to the principle of Separation of Concerns (SoC) is vital for creating clean, maintainable, and scalable code. One of the best practices to achieve SoC is through the use of selector classes. In this blog post, we'll explore what selector classes are, how they contribute to SoC, and how to structure them effectively in your Salesforce projects.

What Are Selector Classes?

Selector classes in Salesforce Apex are dedicated classes that encapsulate the logic for retrieving records from the database. By isolating data retrieval logic in selector classes, you ensure that the code responsible for querying data is separated from the business logic and user interface layers. This separation makes your code more modular, easier to test, and simpler to maintain.

Why Use Selector Classes?

1. Improved Maintainability

When data retrieval logic is centralized in selector classes, any changes to how data is fetched only need to be made in one place. This reduces the risk of introducing bugs and makes updates more straightforward.

2. Enhanced Reusability

Selector classes can be reused across different parts of your application. Instead of writing the same SOQL queries in multiple places, you define them once in a selector class and call the appropriate method wherever needed.

3. Simplified Testing

By isolating data retrieval in selector classes, you can more easily mock database operations during unit testing. This allows you to focus on testing business logic without worrying about database dependencies.

How to Structure Selector Classes

1. Naming Conventions

Selector classes should be named clearly and reflect the object they are retrieving. For example, if you are creating a selector class for the Account object, you might name it AccountSelector.

2. Methods in Selector Classes

Selector classes should contain methods that perform specific queries. Each method should have a clear purpose, such as retrieving a record by ID, fetching a list of active records, or getting records based on certain criteria.

Example Structure:

3. Usage in Service Classes

Selector classes should be called from service classes, which handle the business logic. This approach ensures that your business logic remains clean and focused, without being cluttered with data retrieval operations.

Example Usage in a Service Class:

Best Practices for Selector Classes

• Keep Methods Focused: Each method should perform a single, well-defined task.

• Avoid Business Logic: Selector classes should only handle data retrieval, not business logic or data manipulation.

• Document Methods: Provide clear comments and documentation for each method to ensure other developers understand what each method does.

• Combine with Service Classes: Always use selector classes in conjunction with service classes to maintain a clear separation between data access and business logic.

Conclusion

Using selector classes in Salesforce Apex is a best practice that promotes the Separation of Concerns principle. By structuring your code with dedicated classes for data retrieval, you enhance maintainability, reusability, and testability. Incorporate selector classes into your development practices to keep your code organized and scalable as your Salesforce org grows.

FAQs

1. What is the purpose of a selector class in Salesforce Apex? A selector class is designed to encapsulate the logic for retrieving records from the database, promoting Separation of Concerns by isolating data access from business logic.
2. How do selector classes improve code maintainability? By centralizing data retrieval logic in selector classes, you make it easier to update and maintain the code, as changes to queries only need to be made in one place.
3. Should business logic be included in selector classes? No, selector classes should strictly handle data retrieval. Business logic should be managed in service classes that call the selector classes.
4. Can selector classes be reused across different parts of an application? Yes, selector classes are reusable across different parts of your application, reducing the need for duplicate code and ensuring consistency.
5. How do selector classes simplify testing in Salesforce? Selector classes make it easier to mock database operations during testing, allowing you to isolate and test business logic without dependency on the database.