Object-Oriented Design

Evolving Analysis Models into Design Models

• Analysis models represent the business problem domain as a set of collaborating objects to define functional requirements.
• Design models increase the likelihood of delivering an affordable and easily maintainable system by addressing both functional and nonfunctional requirements.
• Design models refine analysis models by adding system environment details and refining problem domain information.
• Use cases and current classes should be reviewed when evolving analysis models into design models.
• Factoring is the process of separating out a module into a stand-alone module, either a new class or method.
• Abstraction creates a higher-level idea from a set of ideas, while refinement is the opposite.
• Partitions are the object-oriented equivalent of a subsystem, where a subsystem is a decomposition of a larger system into its component systems.
• Collaborations should be identified by creating a communication diagram for each use case and looking at the class diagram to see how the different classes are related.
• Cluster analysis or multiple-dimensional scaling can be used to identify classes that could be grouped to form a collaboration.
• The more messages sent between objects, the more likely the objects belong in the same partition.
• Modeling each collaboration between objects in terms of clients, servers, and contracts can help identify potential partitions.
• Identifying collaborations and partitions helps determine which classes should be grouped together in design.