Customer Validation of Formal Contracts

This paper shows how to write formal OCL contracts for system operations in such way that a translation to natural language (a subset of English), understandable by a customer, can be obtained automatically. To achieve natural language text understandable by a customer we use the vocabulary of the problem domain when writing formal contracts for system operations. The benefits of our approach are that we increase the precision of the model by using formal specifications, and that a customer is able to validate (by viewing the natural language rendering) if a contract actually describes the behavior desired from the system. Without validation of this kind there is generally no guarantee that the formal specification states the correct properties.