32.19. Example: Monopoly Domain Model Refinements
Figure 32.35 shows refinements to the Monopoly domain model. These include:
- Different kinds of property squares (LotSquare , …). This reflects the guideline that if the domain rules treat a noteworthy concept in a different or distinct manner, then show it a separate specialization.
- An abstract superclass PropertySquare . This is justified because all the subclasses have a price attribute and an Owns association with a Player .