Instances and Object Diagrams

1. Instances and Object Diagrams Reporter:陳雅萍

2. Abstractions and Instances • Abstraction: the ideal essence of a thing • Instance: a concrete manifestation of an abstraction • a set of operations may be applied and may have a state that stores the effects of the operation • not stands alone, always tied to an abstraction

3. Objects • is synonymous to instance • something that takes up space in the real or conceptual world • it is possible to change during the abstraction of that object • lives within the context of an operation, a component, or a node

4. Named, Anonymous, Multiple, and Orphan Instances

5. Object State

6. Standard Elements • Stereotypes • instanceOf • instantiate • become • copy • transient

7. Modeling Concrete Instance

8. Modeling Prototypical Instances

9. Object Diagrams • model the instances of things contained in class diagram • a diagram that shows a set of objects and their relationship at a point of time • covers a set of instances of the things found in a class diagram • expresses the static part of an interaction

10. An Object Diagram

11. Contents • Particular contents • Objects • Links • Common contents • name, notes, package and subsystem

12. Common uses • model the static design view or static process view of a system • model static data structure • visualize, specify, construct, and document the existence of certain instances in the system, together with their relationships to one another

13. Modeling Object Structures

14. Object Diagram Properties • no single object diagram need capture everything about a system’s design or process view • reflect some of the concrete or prototypical objects that live in the running system