Kontrollkoppling

Kontrollkoppling is a term used in software engineering to describe a form of module coupling where one module influences the control flow of another by passing control-related information, such as a mode, flag, or operation code. The callee’s behavior is determined by this control information, not solely by the data values it processes.

In the taxonomy of coupling, kontrollkoppling is typically contrasted with data coupling, where modules exchange data without directing each other’s behavior. Kontrollkoppling is generally considered undesirable because it ties the recipient’s behavior to the caller’s intent, reducing modularity, reuse, and testability. It can make the system harder to understand, since changing one module may require changes in the other to maintain correct behavior.

Common patterns include a function that accepts a mode parameter to select between different operations or a method that changes its behavior based on a boolean flag. An example is a print function that takes a flag to decide whether to print to the console or to a file. Such patterns often lead to large conditional blocks inside the callee.

To reduce kontrollkoppling, designs advocate explicit, dedicated interfaces for each operation, or the use of polymorphism or strategy patterns to encapsulate behavior in separate components. Other approaches include splitting multifunction functions into separate, single-purpose functions or adopting data-driven or message-based interactions that avoid conveying control intent through parameters.

Kontrollkoppling relates to broader software design concepts such as cohesion and coupling and is part of standard discussions of architectural quality and maintainability in software engineering.