Class Diagram Quick Start

Access Modifiers

Access modifiers are used for marking members only.

• -: private
• +: public
• #: protected
• ~: package(for some languages that are not fully object-oriented)

Relationships

Relationships are used for marking type only.

Association

--> or <-- or <--> for unidirectional and bidirectional. The weakest relationship.

NOTE

All relationships except inheritance and implementation can have bidirectional case.

Inheritance

<|--: inheritance from left to right. Child <|-- Parent for example. Unidirectional only.

Aggregation

o--: aggregation, type on the right are used inside the type on the left while left is independent. Car o-- Wheel for example.

Composition

*--: composition, an extra rule for class diagram that marks the left as a whole and contains the right, both can't be reasonably exists alone, Human *-- Heart

Implementation

<|..: the left implements the left interface.