sealed class

I’m a strong advocate of the separation of logic principle. In the service layer, we often deal with various I/O operations and interactions with external systems. Not only is it essential to correctly handle exceptions but also make a clear distinction between successful responses and different error scenarios. Kotlin offers sealed classes and interfaces as a powerful tool to establish a predefined hierarchy of subtypes. In this post, I will show you how this feature has proven invaluable, allowing me to keep my code concise without the burden of excessive boilerplate.