Where should code be placed instead of the CODE tab of a PCF?

Placing code in a UI helper class instead of the CODE tab of a PCF (Page Configuration File) aligns with best practices in Guidewire development for several reasons. UI helper classes are designed to encapsulate reusable logic that can be shared across multiple PCFs. This not only encourages code reuse but also promotes the separation of concerns, making the PCF easier to read and maintain.

By keeping the PCF primarily declarative, developers can focus on layout and binding rather than embedding logic directly within. This approach improves maintainability since any changes in the logic can be managed within the UI helper class without requiring modifications to the PCF itself. Furthermore, it makes unit testing easier, as logic contained in helper classes can be tested independently of the UI structure.

Placing code inside the Configuration tab or directly within the Template class is not advisable, as it can lead to a cluttered and difficult-to-manage configuration. The Application layer is also not an appropriate place for UI-specific logic, as it would violate the principles of layering in software architecture, where UI concerns should remain distinct from the application logic. Using a UI helper class thus preserves the modularity and clarity of the application’s structure.