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Software Design with UML

by Somboon Patntirapong

Course Overview

• Focuses on the Object-Oriented Analysis and Design (OOAD)

• Uses the UML as a tool for the OOAD modeling process

Software Requirements

• Java Runtime Environment (JRE)– Recommend Java SE DK 5

• Jude version 5 (UML Tool)

• Others UMLTools– ArgoUML, Poseidon, Visual Paradigm– IBM Rational, Borland Together, MagicDraw

Software Requirements

• References– Learning UML 2.0, Oreilly, Russ Miles, Kim Hamilton, 2006– Use Case Driven Object Modeling with UML—Theory

and Practice, Apress, Doug Rosenberg, Matt Stephens, 2007

– http://java.sun.com– www.omg.org

Course Outline

• Chapter 1: Introduction to OOAD and UML• Chapter 2: UseCase Diagram• Chapter 3: Activity Diagram• Chapter 4: Class Diagram• Chapter 5: Advanced Class Diagram• Chapter 6: Object Diagram• Chapter 7: Sequence Diagram• Chapter 8: Collaboration Diagram• Chapter 9: Component Diagram• Chapter 10: Deployment Diagram

Course Outline

• Chapter 11: Package Diagram• Chapter 12: State Diagram• Hand-on Case Study

Chapter 1

Introduction to OOAD and UML


• Software Development Life Cycle– Requirements and Analysis

– Design

– Development

– Testing

– Deployment


• Well-known Software Development Processes:– Waterfall

– Iterative


• OOAD focuses on analysis and design phases– Use features of OO programing language

• UML as a tool (Modeling Language)– Why not model with code?

• What is Unified Modeling Language (UML)?– Notation

• Why UML?– Standard– Comprehensive and concise– Built on lessons learned


• Degrees of UML– UML as a sketch– UML as a blueprint

• UML consists of diagrams:– UseCase– Activity– Class and Object– Sequence and Collaboration– State– Package– Component and Deployment

Chapter 2

UseCase Diagram

UseCase Diagram• Uses UseCase diagram to model the requirements• Is a starting point of project• Gives you a big picture• Shows who uses the system• Shows the features of the system

UseCase Diagram• Content Management System (CMS) case

• Requirement A1:The content management system shall allow an administrator

to create a new blog account, provided the personal details of the new blogger are verified using the author credentials database.

UseCase Diagram• Actor Element:

– Identifies who or what uses the use cases– Can be a person or a system

UseCase Diagram• Actor Element:

– Generalization/Specialization

UseCase Diagram• UseCase Element:

– Identifies required feature of the system

• Communication Line Element:– Connect an actor and a usecase

UseCase Diagram• System Boundaries Element:

UseCase Diagram• Requirement A2:

The content management system shall allow an administrator to create a new personal Wiki, provided the personal details of the applying author are verified using the author credentials database

UseCase Diagram• <<include>> Element:

– Incorporates behavior

UseCase Diagram• Special Case/Generalization Element:

UseCase Diagram• <<extend>> Element:

– Not always, might or might not

Chapter 3

Activity Diagram

Activity Diagram

• UseCase diagram show what your system should do• Activity diagram show how your system will

accomplish it goals• Shows a procedure or workflow• Similar to flowchart

Activity Diagram

• Initial Node Element:– Starts the activity

• Action Element:– Actions are the active steps in the activity

Activity Diagram

• Flow Element:

• Final Node Element:

Activity Diagram

• Decisions and Merges Element:– Guard : [condition]

Activity Diagram

• Fork and Join Element:– Fork : simultaneous flow– Join : all incoming action must finish before proceed to the

next flow

Activity Diagram

• Object Node Element:– Objects can be passed between actions

Activity Diagram

• Signal Element:– Activity may involve external systems, people, or processes– Eg: authorizing credit card payment– Sending :– Receiving :

Activity Diagram

• Swimlane/Partition Element:– Used to differentiate the participants– Or to group the actions

Activity Diagram

• Case Flow:– The administrator asks the system to create a new blog

account– The administrator selects an account type– The adminstrator enters the author’s details– The author’s details are verified using the author credentials

database– The new blog account is created– A summary of the new blog account’s details are emailed to

the author

• Draw your own one!!

Activity Diagram

Chapter 4

Class Diagram

Class Diagram

• Class diagram shows the classes that you must have to create a system

• So, what is a class?– Class is a blueprint of object

• Program must have at least one class• But normally more than one class (may be a

thousand)• What can the class contain?

– Attributes (Instance Variables)– Operations (Methods)– Constructors

Class Diagram

• Class Diagram:

Class Diagram

• Source code:public class Account{

private double balance;

public Account(double intiBalance){ balance = initBalance; } public boolean deposit(double amt){ .. } public boolean withdraw(double amt){ .. }}

Class Diagram

• Visibility– Private (-)

– Package (~) ( )

– Protected (#)

– Public (+)

• Note:– For Java, protected = package + subclass

Class Diagram

• Class Attributes:– Inline

– Association

Class Diagram

• Multiplicity:– 1 .. 1– 1 .. *– * .. 1– * .. *

Class Diagram

• Attribute Properties

• Source code:

public class CMS{ private final String createdBy = “James & Co..”; ..}

Class Diagram

• Class Operations:

Class Diagram

• Information Hiding– To protect our valuable information (data)– How?

• Encapsulation– We separate the system into many clasess (OO)– BUT each class has protected his own data!!– So, what should we do?

Class Diagram

• Information Hiding/Encapsulation– Can’t apply these concept separately– Otherwise useless!!

Class Diagram

• Static Members:

Chapter 5

Advanced Class Diagram


• Classes can have relationships to one another• A class can be a type of another class; generalization• A class can contain objects of another class in

various way

• Class relationship:– Dependency (weakest)– Association– Aggregation– Composition– Inheritance (strongest)


• Dependency– Dependency between two classes means one class needs

the other class– One class USES another class– Let say, A depends on B– If B changed, A needs to know the changes!!– If A changed, B doesn’t care


• Source Code:

Public class UserInterface{ .. public void main(String args[]){ BlogEntry be = new BlogEntry(); be.setName(“My first blog”); .. }}


• Association:– Means that a class will contain a reference to an object of

the other class– In form of an attribute– Relationship stronger than dependency


• Source code:

public class BlogAccount{ private BlogEntry[] entries; ..}

public class BlogEntry{ ..}


• Association with direction:– Can be unidirection– Or can be bidirection


• Association class:– Resolves complex relationship (Many-to-Many)– Depends on object model


• Aggregation:– Is just a stronger version of association– Owns but may share object of another class– Owned object may have a lifetime outside the owning object– Deletion of Project doesn’t imply that Employee must be

deleted


• Source code:– For java, association and aggregation, coding is not different

public class Project{ private Employee[] emps; ..}

public class Employee{ ..}


• Composition:– Kind of aggregation– But stronger than aggregation– Implies that owned objects can’t live without owning object– Eg, Introduction and MainBody don’t have meaning without

BlogEntry


• Source code:– Association, Aggregation, and Composition, coding is the

same

public class BlogEntry{ private Introduction intro; private MainBody body; ..}


• Generalization:– Inheritance– Is-A relationship or Kind-of relationship– Support multiple inheritance, but beware of conflicts


• Source code:

public class Article{ ..}

public class BlogEntry extends Article{ ..}


• Abstract Classes:– Classes that define functionality without providing full

implementation– Therefore can not be instantiated– Any class that extends an abstract class must implement

abstract method


• Class that extends abstract class:


• Source code:

public abstract class Store{ public abstract void store(Article[] articles); public abstract Article[] retrieve();}

public class BlogStore extends Store{ public void store(Article[] article){ .. } public Article[] retrieve(){ .. }}


• Interface:– Like class that everything is abstract– Is not for extending, but for implementing– Avoids the problem of multiple inheritance– Methods listed in an interface are all abstract


• Class that implements interface:


• Source code:

public interface EmailSystem{ public abstract void send(Message msg);}

public class SMTPMailSystem implements EmailSystem{ public void send(Message msg){ .. }}

Chapter 6

Object Diagram

Object Diagram

• Objects are runtime representation of classes• Objects can be called Instances• Object diagram is very similar to a class diagram• Is useful when you want to describe how the objects

within the system work

Object Diagram

• Object can contain/show data:

Object Diagram

• Links:

Chapter 7

Sequence Diagram

Sequence Diagram

• Is a kind of interaction diagram• Shows interaction between parts of your system• Or identifies the objects involved with each process• Focuses on time sequence• One sequence relates directly to one usecase• You will know how well design of you classes with the

sequence diagram

Sequence Diagram

• Participants and Time Lines:– Usually the object– But can be an external system or people

Sequence Diagram

• Messages and Activation Bars:– Invoking methods/operations

Sequence Diagram

• Nested Messages:

Sequence Diagram

• Synchronous Messages:– Waits for response

Sequence Diagram

• Asynchronous Messages:– Don’t wait for a response– Eg, threading, messaging

Sequence Diagram

• Creation and Destruction Messages:

Sequence Diagram

• Creation Messages:– In Java, using new keyword– Eg, new Account(500);

• Destruction Messages:– In Java, doesn’t have to destroy object– Use garbage collector– So, check your preferred language– Implies no use of destruction message!!

Sequence Diagram

• Back to CMS case• Main flow:

– The administrator asks the system to create a new blog account

– The administrator selects the regular blog account type– The administrator enters the author’s details– The author’s details are checked using the author credential

database– The new regular blog account is created– A summary of the new blog account’s detailss are emailed to

the author• Just for review, because we already have the activity

diagram

Sequence Diagram

• Top-Level Sequence Diagram:

Sequence Diagram

• Detailed Sequence Diagram:– Contain more participants, more precise– But too much details may make the diagram complicated– Details may be the actual user interface of your choice

Sequence Diagram

Chapter 8

Collaboration Diagram


• Another kind of interaction diagram• Alternative to sequence diagram• Objects are concerned with numbered arrows

showing the flow of information• Focuses on link perspective• Called communication diagram in UML 2.0


• Participants, Links, and Messages:– Participants: objects, people, systems– Links: relationship– Messages: invoking methods (operations)


• Nested Messages:– The called method invokes others methods


• Invoking message multiple times:– Format: [i=0..9]


• Sending a message based on a condition:– Format: [condition=true]


• Back to CMS Case– Collaboration vs Sequence Diagrams


• Collaboration VS Sequence Diagrams– What do you think?– Which one do you prefer?

• Sometimes we need both!!

Chapter 9

Component Diagram

Component Diagram

• Component is a reusable part of your software• Eg, libraries

• Component diagram shows:– Packaging of code– Dependencies between components– Can show nested components

Component Diagram

• A basic component:

• Provided and Required Interfaces:

Component Diagram

• Using stereotype notation:– If you want to show the details of interfaces

Component Diagram

• Components working together:– Components usually work together with other components

Component Diagram

• Dependency:– Component depends on other components

Component Diagram

• Artifacts:– Can be libraries– In Java, JAR Files

Chapter 10

Deployment Diagrams

Deployment Diagram

• Shows the physical view of your system• Shows the physical relationships between hardware

components• Shows components within the nodes• Shows the protocol being used between nodes

Deployment Diagram

• Nodes:– Can be systems:– Eg, Application Server, Web Server, Operating System– Can be hardwares:– Eg, Server, Desktop PC

Deployment Diagram

• Communications:– Shows connection with protocols

Deployment Diagram

• Showing components:– Shows components that are deployed in the node

Deployment Diagram

• Node Instances:

Chapter 11

Package Diagrams

Package Diagram

• Used to grouping items especially classes• Also provides namespaces• Helps member visibility

• How good is system without packages?

Package Diagram

• Packages:– Like folder icon– In Java, directories

Package Diagram

• Contents of a package:– Usually classes– Nested packages, finally classes inside

Package Diagram

• Source Code:

package security;

public class Credential{ ..}

Package Diagram

• Showing class with its package (an alternative)

Package Diagram

• Package Dependency

Chapter 12

State Diagrams

State Diagram

• Shows how one object changes over time• Helps understanding of the model• What shoud do/what should not do• Consists of:

– State– Event

• State diagram is heavily used in niches of software such as:– Embedded System– Real-time System

State Diagram

• States:– Status of being at a certain time– Eg, light: on/off

State Diagram

• Transitions:– Represents a change of states from a source state to a

target state– Event/Trigger makes transition

State Diagram

• Complex Transitions:– Contains conditions or guards

State Diagram

• Internal Transition/Action in State:– Entry, Do, Exit

State Diagram

• Initial and Final State:– Starting and ending points

Software Design with UML

• What next?– Design pattern– GoF Design pattern– Enterprise pattern

• Hopefully, you like UML• Enjoy your drawing!!

Thank You,Somboon Patntirapong

Copyright 2007

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