31-Oct-15 Simple UML IB Computer Science

2 What is UML? UML stands for Unified Modeling Language UML is a diagramming language designed for Object- Oriented programming UML can be used to describe: the organization of a program how a program executes how a program is used how a program is deployed over a network …and more

3 Design Patterns Design Patterns describe the higher-level organization of solutions to common problems Design Patterns are a current hot topic in O-O design UML is always used for Design Patterns Design Patterns are used to describe refactorings We will discuss some Design Patterns later on in this course

4 UML is complex UML is a big, complicated diagramming language UML comprises at least seven or eight different kinds of diagrams This talk will cover just a tiny bit of one kind of diagram, the class diagram A class diagram is often all that is needed to describe a particular Design Pattern

5 Class diagrams A class diagram shows classes, interfaces, and their relationships We ’ ll cover most of classes and interfaces, and a few of the most important relationships

6 Classes A class is drawn as a rectangle with two or three compartments: Name of the class Variables [optional] Methods

7 Variables I A variable is written as: visibility name : type where: + means public visibility # means protected visibility - means private visibility means default (package) visibility Example: +length:int

8 Variables II Static variables are underlined An initial value can be shown with =value Example: -numberOfEmployees:int=10 means numberOfEmployees is: private static integer and has 10 as its initial value

9 Methods Methods are written as: visibility name (parameters) : returnType where visibility uses the same syntax variables (+, -, #, blank) parameters are given as name:type if the returnType is void, it is omitted constructors are preceded by «constructor» interfaces are preceded by «interface» an ellipsis (…) indicates omitted methods

10 Example of a class Card cardId:int -copy:boolean=false «constructor» Card(int id) +isKind(desiredKind:int) +isSharable():boolean +toString():String

11 Types of relationships A B Class B extends class A C D 1..4 Class C contains 1 to 4 objects of class D Factory Product creates Other kinds of relations

12 Example: Secret Code program

13 UML tools Rational Rose is the “ real world ” standard; full round- trip code generation Recently acquired by IBM (right under Microsoft ’ s nose!) Together (from Borland) is a lot like Rational Rose I haven ’ t used it in about three years (since before Borland bought it from TogetherSoft) ArgoUML looks interesting (and is open source) BlueJ, of course, displays simple UML diagrams Drawing programs with UML support Visio is a Microsoft tool Dia is a freeware clone of Visio

14 Tool links Rational Rose Together ArgoUML Visio Hard to find info on Microsoft ’ s site! Dia

15 The End