Design by Contract

Design by Contract is a design method that specifies an Operation provided by a software element in terms of obligations and guarantees between its caller and provider. The contract is expressed through Preconditions, Postconditions, and Invariants.

SimpleModeling uses DbC as a basis for making valid Object States and Relationships explicit. For a call satisfying its Preconditions, an Operation guarantees its Postconditions and preserves Object or structural Invariants across execution.