Class Diagram Syntax Reference

Class & Object

Class

Object

Class: abstraction for a group of objects that share the same functionalities and the same characteristics.
Object: phisical creation (or istance) of a class.

Attribute

Attribute (or instance variable or member variable member or class characteristic): characteristic of a class/object.

Operation

Operation (or method o member function): functionality of a class/object.

Member Properties

+ memberName "public member"

Public, protected, private: visibility modifiers.
Static member (or class member): class member.
Abstract Operation: method signature (method without implementation).
Derived attribute: attribute derived from others.

# memberName "protected member"

- memberName "private member"

memberName o $memberName "static member"

operation o operation {abstract} "abstract operation"

/attributeName "derived attribute"

Abstract Class & Interface

Abstract Class

Interface

Abstract class : class thaht cannot be instantied that usually declare abstract methods.
Interface: data structure not istantiable that can declare only abstract methods (and public static constants).

Extension & Implementation

Extension

Implementation

Extension: inheritance relationship beetween classes.
Implementation: extension to implement abstract methods of an interface.

Association & Link

Association

Link

Association : relationship beetween classes where one uses the services (the operations) provided from the other.
Link: association relationship beetween objects.

Aggregation

Aggregation: association characterized from containment.

Composition

Composition: aggregation with coincident life line.

Navigability

Navigability: direction of an association.

Multiplicity

Molteplicity: correspondence beetween the caridinality of the objects of the classes involved in the association.

Role Names

Role names: description of a class behavior in an association.

Qualified Association

Qualified association : association in which a class object is identified from another class through
a sort a "foreign key".

Association Class

Association class : Association coded as a class.