Layerintroduces

Layerintroduces is a term used in software architecture to describe the deliberate introduction of a new architectural layer within a system, with the aim of improving separation of concerns and reducing coupling between components. It is not a formal pattern with a universally defined specification; rather, it is a descriptive label used in discussions of modernization, refactoring, or architectural design.

Common scenarios include adding a domain or service layer between the presentation and data access layers, introducing an abstraction that encapsulates business rules, validation, or workflow, and providing a stable API for higher layers while isolating changes in lower layers. The process typically involves designing the layer's responsibilities, defining clear interfaces, and refactoring existing callers to depend on these interfaces rather than on concrete implementations. It may also require introducing adapters or data transfer objects to translate between layers.

Benefits of layer introduction include improved maintainability, testability, and the ability to evolve one layer without cascading changes across the system. It can also enable parallel development and easier replacement of technologies in a given layer. Potential drawbacks include added complexity, higher cognitive load, and the risk of over-engineering if the layering is not aligned with actual concerns or performance requirements.

Related concepts include general layering, the single responsibility principle, onion or hexagonal architectures, dependency inversion, and façade or adapter patterns. In practice, layerintroduces is about deliberate architectural discipline rather than a fixed recipe.