CH 06 Considering Objects Q Set Class Type

CH 06: Considering Objects Q Set, Class, Type f…of… Q Objects, Actors, Agents f. Data and Actions • Object-Oriented Design and Development • Intro to UML (Unified modeling Language) Q Diagrams TECH CH 01 Computer Science

Class vs. Object • A class is a collection, a group, a set, or a type of … e. g. Q People Q Student • An object is an instance or an individual of a class e. g. Q People Tom Q Student Marry

Class and its UML Box • Data Q State, attributes • Behavior Q Action, transformation, operation f. Triggered by receipt of particular message, or entrance into a particular state

Relations between Classes • Subclass e. g. Q People f. Student • Hierarchy • Inheritance (is-a)

Association relation between classes • • Public Class Employee { public String last. Name; … public Address home. Address; … } • Public class Address { … } Employee -last. Name : String … -home. Address

Association relation between classes (bidirectional) • • • Public Class Team { Team Linked. List members = new Lisnked. List(); … } • Public class member { Team member. Of; … } Member

Composition and Aggregation

Dependency • A dependency exists between the two if a class uses another class in some fashion

Using Class Diagram to show a design

More UML diagrams

Use case diagram

Activity Diagram

State Diagram

Sequence Diagram

Collaboration Diagram

Package Diagram

OO Design • Identify classes Q A set of objects sharing a common structure and common behaviors Q Looking for Things (nouns) f. Structures f. External systems f. Devices f. Roles f. Operating procedures f. Places f. Organizations f. Things that are manipulated by the system to be builds Q Behaviors f. Verbs

OO Measurement: Metric