Unit 8 - The case study: part 2

Question 1

What are the the characteristics of an analysis class?

Answer 1

. An analysis class focuses on handling functional requirements and postpones the handling of non-functional requirements until design and implementation.

. An analysis class seldom defines or provides any interface in terms of operations and their signatures.

. The behaviour of an analysis class may be outlined by responsibilities, although the detailed assignment of responsibilities is left until design.

. An analysis class defines attributes, although these attributes are at a fairly high level. The types of these attributes are often conceptual and recognisable from the problem domain. These attributes may become
classes themselves in design and implementation.

. An analysis class is involved in relationships, although these relationships are still conceptual. Navigability is not important at this stage, although it will become essential when we come to design.

Question 2

A class diagram involved what tasks?

Answer 2

. using interaction diagrams in verifying preconditions and fulfilling postconditions of the system operations – leading to identification of finer grained operations

. assigning the operations to classes using GRASP patterns:

Expert – responsibility assigned to a class with information to fulfil that responsibility

Creator – responsibility given to classes that maintain, record and contain instances of the class of the newly created object

. revisiting the class diagram to record all the decisions taken; this will be our design model.