Ch06
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The document discusses structural models, class diagrams, and the process of creating CRC cards and class diagrams. It provides definitions of key concepts like classes, attributes, operations, and relationships. It describes the elements of class diagrams including classes, attributes, operations, multiplicities, and how to simplify complex diagrams. It outlines a 7 step process for creating CRC cards and class diagrams including identifying objects, role-playing CRC cards, and reviewing the models.
Ch06
- 1. Chapter 6: Class Diagrams
- 2. Objectives Understand the rules and style guidelines for creating CRC cards, class diagrams, and object diagrams. Understand the processes used to create CRC cards, class diagrams, and object diagrams. Be able to create CRC cards, class diagrams, and object diagrams. Understand the relationship between the structural and use case models.
- 3. Structural Model A formal way of representing the objects that are used and created by a business system People Places Things Drawn using an iterative process First drawn in a conceptual, business-centric way Then refined in a technology-centric way describing the actual databases and files
- 5. Structural Models Main goal : to discover the key data contained in the problem domain and to build a structural model of the objects Problem Domain Solution Domain Structural Modeling
- 6. A Common Language Structural models create a well-defined vocabulary shared by users and analysts Classes created during analysis are not the classes that programmers develop during implementation This refinement comes later Typical structural models: CRC cards Class (and Object) diagrams
- 7. Classes, Attributes, & Operations Classes Templates for instances of people, places, or things Attributes Properties that describe the state of an instance of a class (an object) Operations Actions or functions that a class can perform
- 8. Relationships Describe how classes relate to one another Three basic types in UML Generalization Enables inheritance of attributes and operations Aggregation Relates parts to wholes Association Miscellaneous relationships between classes
- 9. CRC CARDS
- 10. Responsibilities & Collaborations Responsibilities Knowing Doing Collaboration Objects working together to service a request
- 11. Front-Side of a CRC Card
- 12. Back-Side of a CRC Card
- 13. CLASS DIAGRAMS
- 14. Elements of a Class Diagram
- 15. Attribute Visibility Attribute visibility can be specified in the class diagram Public attributes (+) are visible to all classes Private attributes (-) are visible only to an instance of the class in which they are defined Protected attributes (#) are like private attributes, but are also visible to descendant classes Visibility helps restrict access to the attributes and thus ensure consistency and integrity
- 16. Operations Constructor Creates object Query Makes information about state available Update Changes values of some or all attributes
- 17. More Elements of Class Diagrams
- 18. Multiplicities 1 1 1 0..* 1 1..* Exactly one: A department has one and only one boss Zero or more: An employee has zero to many children One or more: A boss is responsible for one or more employees Department Boss Employee Child Boss Employee
- 19. More Multiplicities 1 0..1 1 2..4 1 1..3, 5 Zero or one: An employee can be married to 0 or 1 spouse Specified range: An employee can take 2 to 4 vacations each year Multiple disjoint ranges: An employee can be in 1 to 3 or 5 committees Employee Spouse Employee Vacation Employee Committee
- 21. Simplifying Class Diagrams Fully populated class diagrams of real-world system can be difficult to understand Common ways of simplifying class diagrams: Show only concrete classes The view mechanism shows a subset of classes Packages show aggregations of classes (or any elements in UML)
- 22. Object Diagrams
- 23. CREATING CRC CARDS AND CLASS DIAGRAMS
- 24. Object Identification Textual analysis of use-case information Nouns suggest classes Verbs suggest operations Creates a rough first cut Common object list Incidents Roles
- 25. Patterns Useful groupings of classes that recur in various situations Transactions Transaction class Transaction line item class Item class Location class Participant class
- 26. 7 Steps to Structural Models Create CRC Cards Examine common object lists Role-play the CRC cards Create the class diagram Review the class diagram Incorporate patterns Review the model
- 27. Summary Structural Models CRC Cards Class Diagrams Creating CRC Cards and Class Diagrams