Design by contract
Design by contract (DbC), also known as contract programming, programming by contract and design-by-contract programming, is an approach for designing software.
Description
Design by contract prescribes that software designers should define formal, precise and verifiable interface specifications for software components, which extend the ordinary definition of abstract data types with preconditions, postconditions and invariants.
These specifications are referred to as "contracts", in accordance with a conceptual metaphor with the conditions and obligations of business contracts.
The DbC approach assumes all client components that invoke an operation on a server component will meet the preconditions specified as required for that operation.
Where this assumption is considered too risky (as in multi-channel client-server or distributed computing) the opposite "defensive design" approach is taken, meaning that a server component tests (before or while processing a client's request) that all relevant preconditions hold true, and replies with a suitable error message if not.
See also
- Component-based software engineering
- Computer programming
- Correctness (computer science)
- Defensive programming
- Fail-fast
- Formal methods
- Hoare logic
- Modular programming
- Program derivation
- Program refinement
- Software engineering
- Test-driven development
External links
- Design by contract @ Wikipedia
