hkj-effects

You can decouple business logic from side-effect execution in Java by implementing algebraic effect handlers using Free monads, which model domain operations as data structures interpreted via multiple modes like production IO or deterministic testing.

Mock-free testing uses Id monad interpreters to execute pure, deterministic tests of complex workflows, eliminating the need for external mocks or Spring context while validating business logic against expected outputs.

To build an algebraic effect handler, define your domain operations as a Free monad interface, then generate a corresponding interpreter skeleton that translates these operations into target execution modes like production or audit logging.

Yes, you can interpret the same Java business logic for production and dry-run modes by routing the Free monad data structure through different interpreters, such as IO for production or Id for dry-run fee estimation.

Yes, implementing algebraic effect handlers with Free monads satisfies requirements for compile-time exhaustive operation checking by forcing interpreters to handle every defined operation in the domain algebra interface.

Using Free monads for side-effect management introduces limitations around architectural overhead, requiring boilerplate algebra definitions and interpreter implementations for each distinct domain operation before execution.