oo concept chapt3 part1

8/10/2019 OO Concept Chapt3 Part1

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Chapter 3Modeling With

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Unified Modeling Language(UML)


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Learning Outcome

Describe :

What is meant by a model

2 2010 Bennett, McRobb and Farmer

The distinction between a model and

a diagram

The UML concept of a model


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What is Model?

A model is an abstract representation of asystem, constructed to understand the system

prior to building or modifying it

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s mp e represen a on o rea y ur an,1993]

A model provides a means for

conceptualization and communication of ideasin a precise and unambiguous form

More typically are represented by diagrams


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What is a Diagram?

Abstract shapes are used to representthings or actions from the real world

Diagrams follow rules or standards


The standards make sure that differentpeople will interpret the diagram in the

same way

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Diagrams vs. Models

A diagram illustrates some aspect of a system.A model provides a complete view of a system

at a particular stage and from a particular


perspec ve.A model may consist of a single diagram, but

most consist of many related diagrams and

supporting data and documentation.


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Why Use a Model?

A model is quicker and easier to buildthan the real thing

A model can be used in a simulation


A model can evolve as we learn

We can choose which details to include in

a model

A model can represent real or imaginary

things from any domain


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What is Modeling?

Modeling frequently is used during many of thephases of the software life cycle (e.g., analysis and

design)

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design involve graphic languages (sets of symbols)

The system needs to be examined from various

perspectives and its features need to be modeled

Modeling enables us to cope with the complexity of a

system


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Why modeling?

Building a model for a software system prior to itsconstruction is as essential as having a blueprint

for building a large building

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teams

The use of visual notation to represent or model a

problem can provide us several benefits relating

to clarity, familiarity, maintenance, andsimplification


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Modelling Organizations

Organizations are human activity systems. The situation is complex

Stakeholders have different views


We have to model requirementsaccurately, completely and unambiguously

The model must not prejudge the solution


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Modeling Notations

It is important to have standard notations for

modeling, documenting, and communicatingdecisions

requirements thoroughly

Holes in the models reveal unknown or

ambiguous behavior

Multiple, conflicting outputs to the same input

reveal inconsistencies in the requirements


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Modeling key ideas

Clarity easily can understand the system

Familiarity similar to the way in which theinformation actually is represented and used

Maintenance make chan es faster and less

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errors Simplification simplicity and conceptual

understanding

a model is rarely correct on the first try always seek the advice and criticism of others

avoid excess model revisions, as they can distortthe essence of your model


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What is UML? UnifiedModeling Language

Is a language. It is not simply a notation for drawing

diagrams, but a complete language for capturing

knowledge(semantics) about a subject and expressing

knowledge(syntax) regarding the subject for the

purpose o commun cat on. Applies to modeling and systems. Modeling involves a

focus on understanding a subject (system) and

capturing and being able to communicated in this

knowledge.

It is the result of unifying the information systems and

technology industrys best engineering practices

(principals, techniques, methods and tools).


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What is UML? Convergence of different notations used in object-oriented methods, mainly

OMT (James Rumbaugh and collegues), OOSE (Ivar Jacobson), Booch

(Grady Booch)

They also developed the Rational Unified Process, which became the Unified

Process in 1999

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What is UML?

Nonproprietary standard for modeling software systems,

OMG Convergence of notations used in object-oriented methods

OMT (James Rumbaugh and collegues)

OOSE (Ivar Jacobson)

Current Version: UML 2.2

Information at the OMG portal http://www.uml.org/

Commercial tools: Rational (IBM),Together (Borland), Visual Architect(business processes, BCD)

Open Source tools: ArgoUML, StarUML, Umbrello

Commercial and Opensource: PoseidonUML (Gentleware)


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UML

used for both database and software modeling

version 1.1 was adopted in November 1997 by theObject Management Group (OMG) as a standard

language for object-oriented analysis and design

Initially based on a combination of the Booch, OMT(Object Modeling Technique) and OOSE (Object-

Oriented Software Engineering) methods, UML was

refined and extended by a consortium of several

companies, and is undergoing minor revisions by theOMG Revision Task Force.

Ivar Jacobson is known as the father of Use Cases.

References www.inconcept.com/JCM/April1998/halpin.html15


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Modeling and the UML

The larger the project is , the more importantthe modeling is.

Unified Modeling Language (UML) is the

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language that has been adopted by ObjectManagement Group (OMG)

UML provides a wide variety of notations for

modeling many aspects of software systems


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Different types of

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models


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Conceptual, Logical, andPhysical Models

The products of analysis and design areexpressed through conceptual, logical, and

physical models

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They are expressive enough to allow adeveloper to capture all of the decisions that

need to be made during the analysis of a

system and complete enough to serve asblueprints for implementation


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Conceptual, Logical, and

Physical Models

The conceptual model captures the systemin terms of the domain entities that exist (or

will exist) and their association with other

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suc ent t es o your system The conceptual level of modeling is

performed using the terminology of your

business domain and should be technology-agnostic


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Unified Process and UMLTransition

Construction

Elaboration

Inception

methodology

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Software development is a process in phases This process has to follow a methodology

Each phase is supported by graphs & diagrams

The are different kinds of documents and varioususage of them

UML is an essential language for diagrams, offeringcomputer support as well as the right patterns for thevarious stages of refinement and viewpoints


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UML Diagrams

Every complex system is best approached

through a small set of nearly independentviews of a model no single view is

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The choice of what models or diagrams one

creates has a great influence on how a

problem is encountered and how a

corresponding solution is shaped


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Diagrams in UML

UML diagrams consist of:

icons

two-dimensional symbols

Plan Chapter

Produce

First Draft


pat s Strings

UML diagrams are defined inthe UML specification.

Revise Draft

[satisfied]

[not satisfied]

Add Exercises

Add References

to Bibliography


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Relationship between Models

and Diagrams

Use Case Diagrams are one view of the UseCase Model in the Requirements Model


equ remen s o e

Use CasesInterface

Prototypes

Requirements

List

Initial System

ArchitectureModel

Glossary

Use Case Model

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Use Case Diagrams

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Examples of Models

Requirements Model complete view of requirements

may include other models, such as a Use


Case Model includes textual description as well as sets of

diagrams


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Examples of Models

Behavioural Model shows how the system responds to events

in the outside world and the passage of


time an initial model may just use

Communication Diagrams

a later model will include SequenceDiagrams and State Machines


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Models in UML

A system is the overall thing that is beingmodelled

A subsystem is a part of a system


cons s ng o re a e e emen sA model is an abstraction of a system or

subsystem from a particular perspective

A model is complete and consistent at thechosen level of abstraction


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Models in UML

Different models present different views ofthe system, for example:

use case view


es gn v ew

process view

implementation view

deployment view (Booch et al., 1999)


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PackageDiagram

ClassDiagram

ComponentDia ram

Use CaseDiagram

ActivityDiagram

State

Behavior DiagramsStructure Diagrams

UML Diagrams

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DeploymentDiagram

Object

Diagram

CompositeStructureDiagram

Machine

Diagram

Sequence

Diagram

Communication

Diagram

InteractionOverviewDiagram

TimingDiagram

Interaction Diagrams


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Structure Diagrams

Used to show the static structure ofthe system and how those parts arerelated to each other.

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The element in a structure diagramrepresent the meaningful concepts ofa system, and may include abstract,

real world and implementationconcepts.


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Behavior Diagrams

To express the dynamicbehavioral of the objects in a

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.

Can be described as a series of

changes to the system over time


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Interaction Diagrams Used to describe some type of interactions among the

different elements in the model.

Performed on a per Use Case basis, examine the flow ofmethod call calls within a system.

Performin a com lete anal sis re uires that each Use Case

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must be examined, although in practice only selected Usecases may be examined.

The purposes of interaction diagrams are to visualize the

interactive behavior of the system. Now visualizing interaction

is a difficult task. So the solution is to use different types ofmodels to capture the different aspects of the interaction.

That is why sequence and collaboration diagrams are used to

capture dynamic nature but from a different angle.


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Interaction Diagrams

Sequence diagram displays the time sequence ofthe objects participating in the interaction; consists ofthe vertical dimension (time) and horizontaldimension (different objects)

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Collaboration Diagram

displays an interactionorganized around the objects and their links to oneanother. Numbers are used to show the sequence ofmessages.


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Recap

Describe : What is meant by a model

37

The distinction between a model and

a diagram

The UML concept of a model


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References

Bruegge Dutoit (2010)

Bennet, McRobb and Farmer (2010)

The Elements of UML 2.0 Style, Scott W. Ambler,

on n n erna ona ,

The Object Primer 3rd Edition, Scott W. Ambler,

Cambridge University Press, 2004

UML Distilled: A Brief Guide to the Standard Object

Modeling Language (3rd Edition), Martin Fowler,Addison-Wesley Professional, 2004


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Additional References

Grady Booch,James Rumbaugh,Ivar Jacobson

The Unified Modeling Language User Guide, Addison Wesley,2nd edition, 2005

Commercial UML tools

http://www-306.ibm.com/software/awdtools/developer/java/

Together (Eclipse, MS Visual Studio, JBuilder) http://www.borland.com/us/products/together/index.html

Open Source UML tools

http://java-source.net/open-source/uml-modeling ArgoUML,UMLet,Violet,

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