Part 1 Class and OO Fundamentals

Operations

Operations is what sends the messages in the sequence diagrams, the are the same as saying methods.

Main concepts

Abstraction - we only should focus on the essential aspects, baso only the things that matter outside of the object

Encapsulation - separation of the external information from the internal information

Encapsulation example

Part 2 Associations

Associations - is what allows classes to collaborate by using each others operations

The thing that is circled is the association, it is missing the mutilicities

Multiplicities

Unary binary and ternary

Unary - objects can point to other objects of the same class

Ternary - 11 to many players per 1 year and 1 team

Company does not know about the person objects, i.e. company does dont have a person list

Class Diagram example

Part 4 Special Types of Associations

Part of (relationships)

Composition

Composition - child cannot exist without its parent

Aggregation

Aggregation - parent and child can exist independently

Kind of (relationship)

hierarchical relationships

Inheritance

When a child class is derived from a parent class

Generalisation

When common attributes and methods are assigned to a super class

Example without generalisation

Specialisation

Child classes can have specialised attributes and methods as well as the ones inherited from the parent class

Example without specialisation

Abstract Classes

Class that will have no objects, it is used to he inherited from, for example animal