W2561 UML Class Diagrams

Within these castle walls be forged Mavens of Computer Science ...

— Merlin, The Coder

Research

• Read Class Diagram (Wikipedia)

Key Concepts

• Class Diagrams provide a means for communicating the general, static, conceptual model of an application
• Classes are represented by a box with with three compartments
  • The top compartment contains the name of the class, capitalized and centered
  • The middle compartment contains the attributes (properties) of the class, left-aligned in camel case
  • The bottom compartment contains the operations (methods) of the class, left-aligned in camel case
    • Abstract operations are indicated by using italics for the operation name
• An abstract class is indicated by using italics for the class name
• Visibility notations may be placed in front of the attributes and operations
  • + indicates public access
  • - indicates private access
• Scope notations may be used to specify the scope of attributes and operations
  • An underline indicates classifier (static) scope
  • The lack of an underline indicates instance scope
• A relationship describes logical connections between entities
  • Class-Level relationships
    • Inheritance indicates that one of the classes is a specialized form (subclass) of the other (superclass). This is also known as an is a relationship, e.g. "a dog is a mammal". This is indicated on a diagram by drawing a line from the subclass to the superclass with a hollow triangle on the superclass end.
    • Realization indicates that one of the classes (the client) realizes (implements) the behavior specified by the other class (the supplier or interface). This is indicated on the diagram by drawing a dashed line from the client to the interface with a hollow triangle on the interface end. The interface itself has an <<interface>> tag above the "class" name.
  • Instance-Level relationships