Introduction to UML: Structural and Use Case Modeling.

Introduction to UML:Structural and Use Case Modeling

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Software development process has 5 stages

Requirements analysis and definition: Establish the application’s goals and constraints

in consultation with users Design:

Establish the system’s architecture Implementation and unit testing:

Realize the design as a set of programs or program units Unit testing verifies that each unit meets its specification

Integration and system testing: Integrate the program units and test as a complete

system Maintenance:

Correct errors, improve implementation, and enhance the system’s services as new requirements are discovered

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What is the primary driver of software costs?

Most money and effort spent in testing and maintenance But: 85% of errors are introduced during

requirements analysis and design

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Background

What are object-oriented (OO) methods?

OO methods provide a set of techniques for analyzing, decomposing, and modularizing software system architectures

In general, OO methods are characterized by structuring the system architecture on the basis of its objects (and classes of objects) rather than the actions it performs

What are the benefits of OO?

OO enhances key software quality factors of a system and its constituent components

What is the rationale for using OO?

In general, systems evolve and functionality changes, but objects and classes tend to remain stable over time

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Background

Software Quality Factors:Object-oriented techniques enhance key external and internal software quality factors, e.g.,

1. External (visible to end-users)(a) Correctness(b) Robustness and reliability(c) Performance

2. Internal (visible to developers)(a) Modularity(b) Flexibility/Extensibility(c) Reusability(d) Compatibility (via standard/uniform interfaces)

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Background

OOA, OOD, and OOP

Object-oriented methods may be applied to different phases in the software life-cycle, e.g., analysis, design, implementation, etc.

OO analysis (OOA) is a process of discovery

Where a development team models and under-stands the requirements of the system

OO design (OOD) is a process of invention and adaptation

Where the development team creates the abstractions and mechanisms necessary to meet the system's behavioral requirements determined during analysis

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Who are users for this system?

How to design a registration management system?

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Who are users for this system?

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What is the role for each user?


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What is the role for each user?

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Difference between XML and UML

What is XML?

What is UML?

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XML stands for EXtensible Markup Language

XML was designed to describe data and to focus on what data is. (Widely used in database management)

HTML was designed to display data and to focus on how data looks. (used on WWW)

What is XML?

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UML stands for Unified Modeling Language In the field of software engineering, UML

is a standardized specification language for object modeling.

UML is a general-purpose modeling language that includes a graphical notation used to create an abstract model of a system, referred to as a UML model.

What is UML?

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• 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 of communication.

• 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 industry’s best engineering practices (principals, techniques, methods and tools).

What is UML?

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Unified Modeling Language (UML)

used for both database and software modeling version 1.1 was adopted in November 1997 by

the Object 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 the OMG Revision Task Force.

Ivar Jacobson is known as the father of Use Cases.

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1. Structural Modeling with UMLStructural model: a view of an system that emphasizes the structure of the objects, including their classes, relationships, attributes and operations.

2. Use Case Modeling with UMLuse case model: a view of a system that emphasizes the behavior as it appears to outside users. A use case model partitions system functionality into transactions (‘use cases’) that are meaningful to users (‘actors’).

Topics on UML

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What you will learn: what the UML is and what is it not UML’s basic constructs, rules and diagram

techniques how the UML can model large, complex

systems how the UML can specify systems in an

implementation-independent manner how UML, XML Metadata Interchange (XMI)

and Meta Object Facility (MOF) can facilitate metadata integration

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Quick Tour Why do we model? Why do we develop the UML? Foundation elements Unifying concepts Language architecture Relation to other OMG

technologies

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Modeling is a way of thinking about the problems using models organized around the real world ideas.

A modeling method comprises a language and also a procedure for using the language to construct models.

modeling is the only way to visualize your design and check it against requirements before your crew starts to code.

Why do we model?

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Provide structure for problem solving Experiment to explore multiple solutions Furnish abstractions to manage

complexity Reduce time-to-market for business

problem solutions Decrease development costs Manage the risk of mistakes

Why do we model?

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Tijuana “shantytown”: http://www.macalester.edu/~jschatz/residential.html

The Challenge

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Fallingwater: http://www.adelaide.net.au/~jpolias/FLW/Images/FallingWater.jpeg

The Vision

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Why do we model graphically?

Graphics reveal data. Edward Tufte

The Visual Display of Quantitative Information, 1983

1 bitmap = 1 megaword. Anonymous visual modeler

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The UML is a graphical language for specifying visualizing constructing documenting

the artifacts of software systems Added to the list of OMG adopted

technologies in November 1997 as UML 1.1 Minor revisions are in UML 1.2 (1998), 1.3

(1999), 1.4 (2001), and 1.5 (2003). Major revision is UML 2.0, completed in

2005. The current standard.

Quick Tour

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Define an easy-to-learn but semantically rich visual modeling language

Unify the Booch, OMT, and Object modeling languages

Include ideas from other modeling languages Incorporate industry best practices Address contemporary software development

issues scale, distribution, concurrency, executability, etc.

Provide flexibility for applying different processes

Enable model interchange and define repository interfaces

UML Goals

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OMG UML Evolution

1970: First object-oriented languages (Simula-67, Smalltalk).1980:More than 50 different OOAD languages

cause the users trouble to find complete and appropriate tools.1992:New iterations of methods appear.

Booch ‘93, OOSE (Jacobson), OMT-2 (Rumbaugh)

1995:Unification, UML 0.9 by Booch, Rumbaugh1997:Standardization, UML 1.1 by Booch,

Rumbaugh, Jacobson. Object Management Group (OMG) adapts UML as OOAD standard1999:Evolving standard in version 1.32005:Major revision in version 2.0

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OMG UML Evolution

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OMG UML Specification

UML Summary UML Semantics UML Notation Guide UML Example Profiles

Software Development Processes Business Modeling

Model Interchange Model Interchange Using XMI Model Interchange Using CORBA IDL

Object Constraint Language

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Focus: the Language

language = syntax + semantics syntax = rules by which language

elements (e.g., words) are assembled into expressions (e.g., phrases, clauses)

semantics = rules by which syntactic expressions are assigned meanings

UML Notation Guide – defines UML’s graphic syntax

UML Semantics – defines UML’s semantics

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Building blocks Well-formed rules

Foundation Concepts

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The basic building blocks of UML are: model elements (classes, interfaces,

components, use cases, etc.) relationships (associations, generalization,

dependencies, etc.) diagrams (class diagrams, use case diagrams,

interaction diagrams, etc.) Simple building blocks are used to create

large, complex structures cf. elements, bonds and molecules in

chemistry cf. components, connectors and circuit boards

in hardware

Building Blocks

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Diagram: Class View

Elem ent

Carbon Hydrogen

<<covalent>>

<<covalent>>C

C

C H

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Diagram: Instance View

:Carbon :Carbon

:Hydrogen

:Hydrogen

:Hydrogen

:Hydrogen

:Hydrogen:Hydrogen

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Well-Formed Rules Well-formed: indicates that a model or

model fragment adheres to all semantic and syntactic rules that apply to it.

UML specifies rules for: naming scoping visibility integrity execution

However, during iterative, incremental development it is expected that models will be incomplete and inconsistent.

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Well-Formed Rules (cont’d)

Example of syntactic rules: Class Basic Notation: A class is drawn as a solid-

outline rectangle with three compartments separated by horizontal lines.

Presentation Option: Either or both of the attribute and operation compartments may be suppressed.

Example of syntactic guideline: Class Style Guideline: Begin class names with an

uppercase letter.

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Unifying Concepts class-instance dichotomy

e.g., an object is an instance of a class ORa class is the classifier of an object

specification-realization dichotomy e.g., an interface is a specification of a

class ORa class is a realization of an interface

analysis-time vs. design-time vs. run-time modeling phases (“process creep”) usage guidelines suggested, not enforced

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Structural Modeling

What is structural modeling? Core concepts Diagram tour When to model structure Modeling tips

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What is structural modeling?

Structural model: a view of an system that emphasizes the structure of the objects, including their classes, relationships, attributes and operations.

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Construct Description Syntax

class a description of a set of objects that share the same attributes, operations, methods, relationships and semantics.

interface a named set of operations that characterize the behavior of an element.

component a modular, replaceable and significant part of a system that packages implementation and exposes a set of interfaces.

node a run-time physical object that represents a computational resource.

«interface»

Structural Modeling: Core Elements

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Structural Modeling: Core Elements (cont’d)


constraint¹ a semantic condition or restriction.

{constra in t}

¹ An extension mechanism useful for specifying structural elements.

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association a relationship between two or more classifiers that involves connections among their instances.

aggregation A special form of association that specifies a whole-part relationship between the aggregate (whole) and the component part.

generalization a taxonomic relationship between a more general and a more specific element.

dependency a relationship between two modeling elements, in which a change to one modeling element (the independent element) will affect the other modeling element (the dependent element).

Structural Modeling: Core Relationships

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realization a relationship between a specification and its implementation.

Structural Modeling: Core Relationships (cont’d)

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Show the static structure of the model the entities that exist (e.g., classes,

interfaces, components, nodes) internal structure relationship to other entities

Do not show temporal information

Kinds static structural diagrams

class diagram object diagram

implementation diagrams component diagram deployment diagram

Structural Diagram Tour

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Static Structural Diagrams

Shows a graph of class elements connected by static relationships.

kinds class diagram: class view object diagram: instance view

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Classes

Window

display ()

size: Areavisibility: Boolean

hide ()

Window

Window

+default-size: Rectangle#maximum-size: Rectangle

+create ()

+display ()

+size: Area = (100,100)#visibility: Boolean = true

+hide ()

-xptr: XWindow*

-attachXWindow(xwin:Xwindow*)

{abstract,author=Joe,status=tested}

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Classes: compartments with names

bill no-shows

Reservation

operations

guarantee()cancel ()change (newDate: Date)

responsibilities

match to available rooms

exceptions

invalid credit card

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Classes: method body

report ()

BurglarAlarm

isTripped: Boolean = false

PoliceStation

1 station

*

{ if isTrippedthen station.alert(self)}

alert (Alarm)

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Types and Implementation Classes

Set«type»

addElement(Object)removeElement(Object)testElement(Object):Boolean

* elements

Object«type»

HashTableSet«implementationClass»

addElement(Object)removeElement(Object)testElement(Object):Boolean

1 body

HashTable«implementationClass»

setTableSize(Integer)

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Interfaces: Shorthand Notation

+crea te ()+ log in (U serN am e, P assw d)+ find (S to re Id )+ge tP O S to ta ls (P O S id )+upda teS to reTo ta ls (Id ,S a les)+ge t(Item )

-s to re Id : In teger-P O S lis t: L is t

Store

P O S te rm ina l

P O S te rm ina lH om e

<<use>>

S to reH om e

S to re

POSterm inal

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Interfaces: Longhand Notation

+create()+login(UserNam e, Passwd)+find(StoreId)+getPOStotals(POSid)+updateStoreTotals(Id,Sales)+get(Item )

-storeId: Integer-POSlist: List

Store

POSterm inal

POSterm inalHom e

<<use>>

StoreHom e

POSterm inal

+getPOStotals(POSid)+updateStoreTotals(Id,Sales)+get(Item )

<<interface>>Store

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Associations

Person

Manages

JobCompany

boss

worker

employeeemployer

0..1

Job

Account

Person

Corporation

{Xor}

salary

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Association Ends

Polygon PointContains

{ordered}

3..1

GraphicsBundle

colortexturedensity

1

1

-bundle

+vertex

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PlayerTeam

Year

Record

goals forgoals againstwinslosses

goalkeeper

season

team

ties

Ternary Associations

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Composition

Window

scrollbar [2]: Slidertitle: Headerbody: Panel

Window

scrollbar title body

Header Panel

2 1 1

Slider

111

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Composition (cont’d)

scrollbar:Slider

Window

2

title:Header1

body:Panel1

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Generalization

Shape

SplineEllipsePolygon

Shape

SplineEllipsePolygon

Shared Target Style

Separate Target Style

. . .

. . .

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Generalization

Vehicle

WindPoweredVehicle

MotorPoweredVehicle

LandVehicle

WaterVehicle

venue

venuepowerpower

SailboatTruck

{overlapping} {overlapping}

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Dependencies

«friend»ClassA ClassB

ClassC

«instantiate»

«call»

ClassD

operationZ()«friend»

ClassD ClassE

«refine»ClassC combines

two logical classes

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Dependencies

Controller

DiagramElements

DomainElements

GraphicsCore

«access»

«access»

«access»

«access»

«access»

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Derived Attributes and Associations

Person

birthdate/age{age = currentDate - birthdate}

Company

Person

Department

WorksForDepartment

/WorksForCompany

{ Person.employer=Person.department.employer }

1

1

1employer

employerdepartment

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Objects

triangle: Polygon

center = (0,0)vertices = ((0,0),(4,0),(4,3))borderColor = blackfillColor = white

triangle: Polygon

triangle

:Polygon

scheduler

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Composite objects

horizontalBar:ScrollBar

verticalBar:ScrollBar

awindow : Window

surface:Pane

title:TitleBar

moves

moves

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Links

downhillSkiClub:Club Joe:Person

Jill:Person

Chris:Person

member

member

member

treasurer

officer

president

officer

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Constraints and Comments

Member-of

Chair-of

{subset}Person Committee

Person Company

boss

{Person.employer =Person.boss.employer}

employeremployee

0..1

0..1

1

Representsan incorporated entity.

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Class Diagram Example

+getOrderStatus+setOrderStatus+getLineItem s+setLineItem s+getCreditApproved+setCreditApproved

...

OrderBean{abstract}

LineItem{abstract}

Product

1

*

1

*

<<interface>>EntityBean

CreditCard{abstract}

Custom er

PM Order

PM LineItem

PM CreditCard

*

1

*

buyer

order

order

item

item

com m odity

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Implementation Diagrams

Show aspects of model implementation, including source code structure and run-time implementation structure

Kinds component diagram deployment diagram

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Shows the organizations and dependencies among software components

Components may be specified by classifiers (e.g.,

implementation classes) implemented by artifacts (e.g., binary,

executable, or script files)

Component Diagram

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Components

<<Entity>>030303zak:Order

O rderH om e

O rder

O rderP K

<<Session>>ShoppingSession

S hopp ingS ess ionH om e

S hopp ingS ess ion

O rderIn fo

<<focus>>:Order

<<auxiliary>>:OrderPK

<<auxiliary>>:OrderInfo

O rderH om e

O rder

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Component Diagram

<<EJBEntity>>Catalog

CatalogHom e

Catalog

CatalogPK

<<EJBSession>>ShoppingSession

ShoppingSessionHom e

ShoppingSession

CatalogInfo

<<file>>CatalogJAR

<<focus>>Catalog

<<auxiliary>>CatalogPK

<<auxiliary>>CatalogInfo

CatalogHom e

Catalog

<<EJBEntity>>ShoppingCart

ShoppingCartHom e

ShoppingCart

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Component Diagram with Relationships

<<ejbEntity>>Catalog

<<auxiliary>>CatalogInfo

<<focus>>Catalog

<<res ide>> <<res ide>>

<<auxiliary>>CatalogPK

<<res ide>>

<<file>>CatalogJAR

<<im plem ent>>

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Deployment Diagram

Shows the configuration of run-time processing elements and the software components, processes and objects that live on them

Deployment diagrams may be used to show which components may run on which nodes

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Deployment Diagram (1/2)

:DBServer

videoStoreServer:AppServer

<<Container>> V ideoStoreApplication

:Client

<<brow ser>>:OpenSourceBrow ser

<<Session>>ShoppingSession

<<Focus>>ShoppingSession

<<Entity>>Catalog

<<Focus>>Catalog

<<Entity>>ShoppingCart

<<Focus>>ShoppingCart

<<database>>:VideoStoreDB

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Deployment Diagram (2/2)

backupServer:AppServer

backupBroker:BondBroker

:QuoteService<<database>>:AccountsDB

prim aryServer:AppServer

prim aryBroker:BondBroker

:QuoteService

<<database>>:AccountsDB

<<becom e>>

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When to model structure

Adopt an opportunistic top-down+bottom-up approach to modeling structure

Specify the top-level structure using “architecturally significant” classifiers and model management constructs

Specify lower-level structure as you discover detail re classifiers and relationships

If you understand your domain well you can frequently start with structural modeling; otherwise

If you start with use case modeling (as with a use-case driven method) make sure that your structural model is consistent with your use cases

If you start with role modeling (as with a collaboration-driven method) make sure that your structural model is consistent with your collaborations

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Structural Modeling Tips Define a “skeleton” (or “backbone”) that can be

extended and refined as you learn more about your domain.

Focus on using basic constructs well; add advanced constructs and/or notation only as required.

Defer implementation concerns until late in the modeling process.

Structural diagrams should emphasize a particular aspect of the structural model contain classifiers at the same level of abstraction

Large numbers of classifiers should be organized into packages

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Interface-Based Design Interface-based design is a design approach

that emphasizes the specification of system interfaces separates the specification of service operations

(interfaces) from their realization (implementation) CORBA IDL is typically used for interface-

based design of CORBA applications defines interfaces for business and system objects

without constraining their implementations defines the structure of an distributed application doesn’t allow you to specify object behavior or

class relationships other than generalization

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Interface-Based Design (cont’d)

The following example shows how UML can model the interfaces for a Point of Sale application originally specified in CORBA IDL.

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Example: Interface-based design

module POS{ typedef long POSId; typedef string Barcode;

interface InputMedia { typedef string OperatorCmd;

void barcode_input(in Barcode item); void keypad_input(in OperatorCmd cmd); };

interface OutputMedia { boolean output_text(in string string_to_print ); };…..

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Example: Interface-based design

….. interface POSTerminal { void login(); void print_POS_sales_summary(); void print_store_sales_summary(); void send_barcode( in Barcode

item); void item_quantity( in long

quantity); void end_of_sale(); };

};

#endif /* _POS_IDL_ */

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Point-of-Sale

POSterm inal

+outputText()

«IDLinterface»IOutputM edia

InputM edia +initialization()+barcodeInput()+keypadInput()

+POSref : POSterm inal

«IDLinterface»IinputM edia

OutputM edia

Store

+initialization()+findPrice()

+depotRef : Depot+taxRef : Tax+storeMarkup : float+storeId : Integer

«IDLinterface»IS toreAccess

+initialization()+calculateTax()+findTaxablePrice()

+rate : float

«IDLinterface»ITax

+initialization()+login()+printPOSsalesSummary()+printS toreSalesSummary()+setItemQuantity()+sendBarcode()+endSale()

+storeRef : S tore+storeAccessRef : S toreAccess+outputMediaRef : OutputMedia+taxRef : Tax+POSid : Integer+item Barcode : Integer+item Quantity : Integer+item Info : Item Info+item Price : Currency+item TaxPrice : Currency+item Extension : Currency+saleSubtotal : Currency+taxableSubtotal : Currency+saleTotal : Currency+saleTax : Currency+POSlist : List

«IDLinterface»IPOSterm inal

+initialization()+login()+getPOStotals()+updateStoreTotals()

+totals : Totals+POSlist : List

«IDLinterface»IS tore

StoreAccess

Tax

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Use Case Modeling

What is use case modeling? Core concepts Diagram tour When to model use cases Modeling tips Example: Online HR System

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What is use case modeling?

use case model: a view of a system that emphasizes the behavior as it appears to outside users. A use case model partitions system functionality into transactions (‘use cases’) that are meaningful to users (‘actors’).

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Use Case Modeling: Core Elements


use case A sequence of actions, including variants, that a system (or other entity) can perform, interacting with actors of the system.

actor A coherent set of roles that users of use cases play when interacting with these use cases.

system boundary

Represents the boundary between the physical system and the actors who interact with the physical system.

UseCaseNam e

ActorNam e

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association The participation of an actor in a use case. i.e., instance of an actor and instances of a use case communicate with each other.

generalization A taxonomic relationship between a more general use case and a more specific use case.

extend A relationship from an extension use case to a base use case, specifying how the behavior for the extension use case can be inserted into the behavior defined for the base use case.

Use Case Modeling: Core Relationships

<<extend>>

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include An relationship from a base use caseto an inclusion use case, specifyinghow the behavior for the inclusion usecase is inserted into the behaviordefined for the base use case.

Use Case Modeling: Core Relationships (cont’d)

<<include>>

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Shows use cases, actor and their relationships

Use case internals can be specified by text and/or interaction diagrams

Kinds use case diagram use case description

Use Case Diagram Tour

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Customer

Supervisor

SalespersonPlace

Establishcredit

Check

Telephone Catalog

F ill orde rs

Shipping Clerk

status

order

Use Case Diagram

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Use Case Relationships

additional requests :

OrderProduct

SupplyArrange

«include»«include»«include»

RequestCatalog

«extend»Extension points

PaymentCustomer Data

after creation of the order

Place Order

1 * the salesperson asks forthe catalog

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Actor Relationships

EstablishCredit

PlaceOrder

Salesperson

Supervisor

1 *

1 *

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Use Case Description: Change Flight

Actors: traveler, client account db, airline reservation system Preconditions:

Traveler has logged on to the system and selected ‘change flight itinerary’ option

Basic course System retrieves traveler’s account and flight itinerary from client account database System asks traveler to select itinerary segment she wants to change; traveler selects itinerary segment. System asks traveler for new departure and destination information; traveler provides information. If flights are available then … System displays transaction summary.

Alternative courses If no flights are available then …

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When to model use cases Model user requirements with use

cases. Model test scenarios with use cases. If you are using a use-case driven

method start with use cases and derive your

structural and behavioral models from it.

If you are not using a use-case driven method make sure that your use cases are

consistent with your structural and behavioral models.

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Use Case Modeling Tips

Make sure that each use case describes a significant chunk of system usage that is understandable by both domain experts and programmers

When defining use cases in text, use nouns and verbs accurately and consistently to help derive objects and messages for interaction diagrams

Factor out common usages that are required by multiple use cases

If the usage is required use <<include>> If the base use case is complete and the usage may be

optional, consider use <<extend>> A use case diagram should

contain only use cases at the same level of abstraction include only actors who are required

Large numbers of use cases should be organized into packages

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Example: Online HR System

Online HR System

LocateEm ployees

UpdateEm ployee

Profile

Update Benefits

Access TravelSystem

Access PayRecords

Em ployee

M anager

Healthcare Plan System

{if currentMonth = Oct.}

{readOnly}

Insurance P lan System

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Online HR System: Use Case Relationships

Update M edicalP lan

Update DentalP lan

Update Benefits______________Extension pointsbenefit options:

after required enrollm ents

UpdateInsurance P lan

Em ployee

<<include>> <<include>> <<include>>

ElectReim bursem entfor Healthcare

Elect StockPurchase

<<extend>>em ployee requestsstock purchase option

<<extend>>em ployee requestsreim bursem ent option

extensioncondition

extension pointname andlocation

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Online HR System: Update Benefits Use

Case

Actors: employee, employee account db, healthcare plan system, insurance plan system Preconditions:

Employee has logged on to the system and selected ‘update benefits’ option

Basic course System retrieves employee account from employee account db System asks employee to select medical plan type; include Update Medical Plan. System asks employee to select dental plan type; include Update Dental Plan. …

Alternative courses If health plan is not available in the employee’s area the employee is informed and asked to select another plan...

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UML is effective for modeling large, complex software systems

It is simple to learn for most developers, but provides advanced features for expert analysts, designers and architects

It can specify systems in an implementation-independent manner

10-20% of the constructs are used 80-90% of the time

Structural modeling specifies a skeleton that can be refined and extended with additional structure and behavior

Use case modeling specifies the functional requirements of system in an object-oriented manner

Ideas to Take Away

Introduction to UML: Structural and Use Case Modeling.

Documents

Transcript of Introduction to UML: Structural and Use Case Modeling.