SEG 4110 Advanced Software Design and Reengineering TOPIC

SEG 4110 – Advanced Software Design and Reengineering TOPIC A Review of UML

What is UML? The Unified Modelling Language is a standard graphical language for modelling object oriented software • Developed when Booch, Rumbagh and Jacobson merged their approaches. • In 1997 the Object Management Group (OMG) started the process of UML standardization SEG 4110 - Topic A- Review of UML 2

Reminder about Naming classes • Use capital letters —E. g. Bank. Account not bank. Account • Use singular nouns • Use the right level of generality —E. g. Municipality, not City • Make sure the name has only one meaning —E. g. ‘bus’ has several meanings SEG 4110 - Topic A- Review of UML 3

Umple A technology for programming in UML • Model-Oriented Programming Adds associations and attributes to programming languages • Java • PHP • Ruby Stand alone code-generator is online at • http: //cruise. site. uottawa. ca/umpleonline/index. php SEG 4110 - Topic C - Advanced UML and Umple 4

Declaration of classes and attributes in Umple class Student { student. Number; // defaults to String grade; Integer entry. Average; // implemented as int } Open in Umple. Online SEG 4110 - Topic C - Advanced UML and Umple 5

Associations class Student { id; name; } class Course { description; code; } class Course. Section { section. Letter; 1. . * -- 1 Course; } association { * Course. Section; * Student registrant; } Open the above in Umple. Online SEG 4110 - Topic C - Advanced UML and Umple 6

Selected patterns class University { singleton; String name; } Open the above in Umple. Online SEG 4110 - Topic C - Advanced UML and Umple 7

Reminder about Labelling associations • Each association can be labelled, to make explicit the nature of the association SEG 4110 - Topic A- Review of UML 8

Analyzing and validating associations 1 • Many-to-one —A company has many employees, —An employee can only work for one company. - This company will not store data about the moonlighting activities of employees! —A company can have zero employees - E. g. a ‘shell’ company —It is not possible to be an employee unless you work for a company Employee * works. For SEG 4110 - Topic A- Review of UML 1 Company 9

Analyzing and validating associations 2 • Many-to-many —A secretary can work for many managers —A manager can have many secretaries —Secretaries can work in pools —Managers can have a group of secretaries —Some managers might have zero secretaries. —Is it possible for a secretary to have, perhaps temporarily, zero managers? Assistant * 1. . ** supervisor SEG 4110 - Topic A- Review of UML Manager 10

Analyzing and validating associations 3 • One-to-one —For each company, there is exactly one board of directors —A board is the board of only one company —A company must always have a board —A board must always be of some company 1 1 SEG 4110 - Topic A- Review of UML 11

Analyzing and validating associations Avoid unnecessary one-to-one associations Avoid this do this SEG 4110 - Topic A- Review of UML 12

Association classes • Sometimes, an attribute that concerns two associated classes cannot be placed in either of the classes • The following are equivalent SEG 4110 - Topic A- Review of UML 13

Reflexive associations • It is possible for an association to connect a class to itself class Course { * prerequisite -- * Course successor; * self multually. Exclusive; } Open in Umple (the symmetric reflexive association doesn’t show graphically yet) SEG 4110 - Topic A- Review of UML 14

Directionality in associations • Associations are by default bi-directional • It is possible to limit the direction of an association by adding an arrow at one end • Open in Umple SEG 4110 - Topic A- Review of UML 15

Object Diagrams • A link is an instance of an association —In the same way that we say an object is an instance of a class SEG 4110 - Topic A- Review of UML 16

Inheritance and the Isa Rule Inheritance • The implicit possession by all subclasses of features defined in its superclasses Always check generalizations to ensure they obey the isa rule • “A checking account is an account” • “A village is a municipality” Should ‘Province’ be a subclass of ‘Country’? • No, it violates the isa rule —“A province is a country” is invalid! SEG 4110 - Topic A- Review of UML 17

Inheritance, Polymorphism and Variables SEG 4110 - Topic A- Review of UML 18

Avoiding unnecessary generalizations Inappropriate hierarchy of classes, which should be instances Improved class diagram, with its corresponding instance diagram : Recording. Category video audio subcategory subcategory : Recording. Category music video jazz blues classical rock : Recording 9 th Symphony Beethoven Let it be The Beatles SEG 4110 - Topic A- Review of UML 19

Avoiding having instances change class • An instance should never need to change class SEG 4110 - Topic A- Review of UML 20

Composition • A composition is a strong kind of aggregation —if the aggregate is destroyed, then the parts are destroyed as well SEG 4110 - Topic A- Review of UML 21

Interfaces An interface describes a portion of the visible behaviour of a set of objects. • An interface is similar to a class, except it lacks instance variables and implemented methods SEG 4110 - Topic A- Review of UML 22

OCL – More to come in a later lecture SEG 4110 - Topic A- Review of UML 23

Use Case Diagrams SEG 4110 - Topic A- Review of UML 24

Example of generalization, extension and inclusion SEG 4110 - Topic A- Review of UML 25

Example Description of a Use Case SEG 4110 - Topic A- Review of UML 26

Sequence diagrams – an example SEG 4110 - Topic A- Review of UML 27

Sequence Diagrams – an example with replicated messages • An iteration over objects is indicated by an asterisk preceding the message name SEG 4110 - Topic A- Review of UML 28

Sequence Diagrams – an example with object deletion • If an object’s life ends, this is shown with an X at the end of the lifeline SEG 4110 - Topic A- Review of UML 29

State Diagrams – an Example of Transitions with Time-outs and Conditions SEG 4110 - Topic A- Review of UML 30

State Diagrams – Example with Conditional Transitions - Course. Section class Planned open. Registration close. Registration Cancelled Open. Not. Enough. Students cancel class. Size >= minimum close. Registration Closed Open. Enough. Students class. Size >= maximum request. To. Register (a. Student) /create. Registration SEG 4110 - Topic A- Review of UML 31

State Diagram – An Example with Substates Course. Section Class Again Open the previous page and this one in Umple SEG 4110 - Topic A- Review of UML 32

Activity Diagrams – An Example – Course Registration SEG 4110 - Topic A- Review of UML 33

Package Diagrams SEG 4110 - Topic A- Review of UML 34

Example of Multi-Layer Systems SEG 4110 - Topic A- Review of UML 35

Component Diagrams SEG 4110 - Topic A- Review of UML 36

An Example of a Distributed System SEG 4110 - Topic A- Review of UML 37

Example of a Broker System SEG 4110 - Topic A- Review of UML 38

Example of a Pipe-and-Filter System Sound Processing SEG 4110 - Topic A- Review of UML 39

Example of the MVC Architecture for a User Interface SEG 4110 - Topic A- Review of UML 40

Example of the Service-Oriented Architecture SEG 4110 - Topic A- Review of UML 41

Abstraction-Occurrence SEG 4110 - Topic A- Review of UML 42

Abstraction-Occurrence Square variant SEG 4110 - Topic A- Review of UML 43

General Hierarchy SEG 4110 - Topic A- Review of UML 44

Player-Role SEG 4110 - Topic A- Review of UML 45

Singleton SEG 4110 - Topic A- Review of UML 46

Observer SEG 4110 - Topic A- Review of UML 47

Delegation SEG 4110 - Topic A- Review of UML 48

Façade SEG 4110 - Topic A- Review of UML 49

Proxy SEG 4110 - Topic A- Review of UML 50

Deployment Diagrams SEG 4110 - Topic A- Review of UML 51