The solution is to re-examine the use cases and the corresponding sequence diagrams to find that missing behaviour. Incomplete behaviour in a class either indicates that some of the sequence diagrams missed some behaviour, or that there are missing use cases (e.g., a class without a service to create objects). This information is directly and immediately available from the sequence diagrams. The services are all the messages received by the class with the stereotype: service. For the Object Model, the verification we carry out involves looking at all the identified classes and their services in the sequence diagrams. The conceptual schema in OO-Method is composed of an Object Model, a Dynamic Model and a Functional Model as was explained in Section 3.2. That is, we look for completeness and feasibility. The validation consists of reviewing each one of the use cases and its corresponding sequence diagrams with the user to see that they provide the behaviour implied in the use case specification. It is also cross-reference -based because there are tags included between elements at different abstraction levels (e.g., use cases have tags pointing to leaves in the function refinement tree). It is structural because there are structural relationships between the elements in the conceptual schema and the different elements in the RAP and CM (e.g., classes in the conceptual schema are classes used in sequence diagrams). The traceability model we use is the structural and cross-reference -based model according to Gotel’s work. In this context, validation, verification and traceability are key issues. The purpose of the RAP is to obtain a consistent first version of the conceptual schema. This process should be evaluated together with the users during and after its construction. In this way, the process continues until all the steps are specified in their corresponding sequence diagram. The object that recognises the need and invokes this responsibility (the client) is an instance of the class Sale-line. We named this responsibility change_stock and allocated it to the previously detected class component Item. Another responsibility is to update the item stock. These calculations should later be a derived attribute in terms of the sold items and the corresponding tax calculations. This action implies the responsibility of calculating the total amount of the sales transaction.

Uml sequence diagram online sales