Structural Modeling Objects

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.

Relationships

• Describe how classes relate to one another.
• Three basic types in UML:
  • Generalization:
    • Enables inheritance of attributes and operations.
    • Represents relationships that are “a-kind-of”.
  • Aggregation:
    • Relates parts to wholes or assemblies.
    • Represents relationships that are “a-part-of” or “has-parts”.
  • Association:
    • Miscellaneous relationships between classes.
    • Usually a weaker form of aggregation.

Object Identification

• Textual analysis of use-case information:
  • Nouns suggest classes.
  • Verbs suggest operations.
• Creates a rough first cut to provide an object list.
• Brainstorming: People offering ideas.
• An initial list of classes (objects) is developed.
• Attributes, operations, and relationships to other classes can be assigned in a second round.

Common Object Lists

• Physical things
• Incidents
• Roles
• Interactions
• Patterns:
  • Useful groupings of collaborating classes that provide solutions to common problems (are reusable).
  • Developed patterns provide a starting point for work in similar domains.