Implementationsuch

Implementationsuch is a theoretical concept in software engineering and requirements engineering that describes a formal approach to documenting how concrete implementations satisfy given requirements. The term combines "implementation" and "such" to emphasize constraint-driven selection of implementations rather than prescribing a single solution. In practice, an Implementationsuch statement specifies a set of constraints a component must satisfy, enabling traceability from requirements to code and allowing multiple viable implementations to coexist.

Key aspects of Implementationsuch include a focus on specification-oriented guidance, decoupling between interfaces and their realizations, and a negotiable binding between requirements and concrete components. It is often used in product line engineering, where multiple variants must satisfy a common interface and meet shared constraints. In documentation, an Implementationsuch note accompanies an interface or contract, listing required capabilities and non-functional constraints such as performance, security, and compatibility.

Relation to other concepts: Implementationsuch aligns with constraint-based design and feature-oriented development, and shares ideas with such-that constraints in formal specification languages. It can complement design-by-contract approaches by explicitly recording the conditions under which a particular implementation is acceptable.

Examples: an interface IStorage may have implementations labeled as Implementationsuch with properties like supports encryption, supports caching, and persists to either SQL or NoSQL stores. In a system architecture description, a component P is described as Implementationsuch if its concrete realization meets latency and reliability constraints specified for that context.

Criticism notes that the concept can be ambiguous without standardized notation or tooling, but proponents argue it improves clarity and traceability by foregrounding constraints and alternative realizations. See also requirements traceability, constraint-based design, software product line, design by contract.