UNIT-I(Unified_Process_and_Use Case_Diagrams)_OOAD.ppt

CS8592 – OBJECT ORIENTED
ANALYSIS AND DESIGN
(III YEAR/VI SEM)
(ANNA UNIVERSITY – R2017)

UNIT I
UNIFIED PROCESS AND USE CASE
DIAGRAMS

Introduction to OOAD
Object Orientated System Development:
 Object oriented method of building software
 Software is a collection of discrete objects that
encapsulates their data and the functionality that
manipulates the data

Introduction to OOAD (Contd.)
In OO System,
 Everything is an object(Any real world entity).
Example: Customer, Car, Book, Hotel, Pilot, etc…
 Each object is responsible for itself.
 Each object has an attributes(data) and methods (functions).
Example: Car has an attributes such as model no, color, speed,
cost. It has methods start(), accelerate(), turnright(), turnleft(),
gearup(), geardown(), stop().
 Objects are grouped into classes
 Interactions through message passing (A sender object sends a
request (message) to another object (receiver) to invoke a
method of the receiver object’s)

OOAD Example
Class Car
Attributes
 Model
 Location
 #Wheels = 4
Operations
 Start
 Accelerate
<<instanceOf>>
<<instanceOf>>
<<instanceOf>>

Why Object Orientation? (Benefit of object orientation)
 Higher levels of abstraction
 Objects encapsulates data (attributes) and functions(methods). So
internal details are hidden from outside.
 Support abstraction at object level.
 Seamless transition among different phases of software development
 Reduce the level of complexity and redundancy makes for clearer
and robust system development.
 Encouragement of good programming techniques
 Easy to produce more modular and reusable code through classes
and inheritance using OO language (C++,java…)
 Promotion of reusability
 Classes are designed generically with reuse as a constant
background goal in OO system using inheritance.

Why Object Orientation? (Benefit
of object orientation (Contd.)
Object-Oriented Analysis
An investigation of the problem (rather than
how a solution is defined)
During OO analysis, there is an emphasis on
finding and describing the objects (or concepts)
in the problem domain.
For example, concepts in a Library Information
System include Book, and Library.
Also called domain objects, entities.

Why Object Orientation? (Benefit of object orientation
Object-Oriented Design
Emphasizes a conceptual solution that fulfills the
requirements.
Need to define software objects and how they
collaborate to meet the requirements.
For example, in the Library Information System, a Book
software object may have a title attribute and a
getBookDetails() method.
• What are the methods needed to process the
attributes?
Designs are implemented in a programming language.
In the example, we will have a Book class in Java.

Analysis, Design and Construction
Book
Title : string
public class Book {
private String title;
public void getBookDetails()
{...}
}
Book
(concept)
Analysis
investigation
of the problem
Design
logical solution
Construction
code
Domain concept Visual Representation of
Domain concepts
Representation in an
object-oriented
programming language.
getBookDetails(
)

Analysis, Design and Construction (Contd.)
 Analysis: - investigate the problem and the
requirements.
 What is needed? Required functions? Investigate
domain objects.
 Problem Domain
 The Whats of a system.
 Do the right thing (analysis)
 Design:
 Conceptual solution that meets requirements.
 Not an implementation
 E.g. Describe a database schema and software objects.
 The Solution Domain
 The ‘Hows’ of the system
 Do the thing right (design)

 OOA: we find and describe business objects or
concepts in the problem domain
 OOD: we define how these software objects
collaborate to meet the requirements.
 Attributes and methods.
 OOP: Implementation: we implement the design
objects in, say, Java, C++, C#, etc.
Analysis, Design and Construction (Contd.)

Unified Process (UP)
• The Unified Process is a popular iterative
software development process for building
object oriented system.
• Iterative and evolutionary development
involves relatively early programming and
testing of a partial system, in repeated cycles.
• It typically also means that development starts
before the exact software requirements have
been specified in detail;
• Feedback (based on measurement) is used to
clarify, correct and improve the evolving
specification

Unified Process (UP) -Advantages
 Iterative and Incremental
 Architecture Centric
 Risk focussed

Inception
 Communication and Planning
 Feasibility study
 Establish the business case for the project
 Establish the project scope and boundary condition
 Outline the usecases and key requirements
 Outline the rough architecture
 Identify risks
 Prepare rough project schedule and cost estimation.
Phases of Unified process (contd.)

Elaboration
 Planning and Modelling
 Refines and expands the preliminary use cases that were
developed as part of the inception phase.
 Expands the architectural representation to include five
different views of the software such as Use case model,
Requirements model, Design model, Implementation
model and Deployment model.
 Establish and validate system architecture through
implementation of executable architecture base line (Partial
implementation of the system contains only core functionality) .
Its built in series of small time boxed iterations.
 Final elaboration phase deliverable is plan for construction
phase (include cost and schedule)

Construction
 Remainder of the system is built on foundation laid
in elaboration phase
 System features are implemented in series of short
time boxed iterations.
 Each iteration results in executable release of
software
 As components are being implemented, unit tests
are designed and executed for each and Integration
activities are conducted.
.

Transition
 System is deployed to target users
 Feedback received from initial release may result in further
refinement.
 The software team creates the necessary support information
(e.g., User manuals, Troubleshooting guides, installation
procedures) that is required for the release.
 At the conclusion of the transition phase, the software increment
becomes a usable software release
Production
 The ongoing use of the software is monitored, support for the
operating environment (infrastructure) is provided, and defect
reports and requests for changes are submitted and evaluated.

UML Diagrams
(Unified Modeling Language )
 A language for visualizing, specifying, constructing, and
documenting the artifacts of a software-intensive system
 The UML is a very important part of developing object
oriented software and the software development
process.
 UML is a modeling language to express and design
documents, software.
 Particularly useful for OO design
 Independent of implementation language

Goals in design of UML
 Provide users a ready – to use expressive visual modeling
language so they can develop and exchange meaningful models.
 Provide extensibility and specialization mechanism to extend the
core concepts.
 Be independent of particular programming language and
development process.
 Provide a formal basis for understanding the m7. odeling
language.
 Encourage the growth of the OO tools market.
 Support higher – level development concepts.
 Integrate best practices and methodologies.

 Three ways to apply UML
 UML as a sketch – informal and incomplete diagram to explore
difficult parts of problem
 UML as blueprint – Detailed design diagrams used either for
reverse engineering(Code to diagram) and forward
engineering(diagram to code).
 UML as programming language – complete executatble
specification of software system in UML. Executable code will
be automatically generated.
 Three perspectives to apply UML
 Conceptual Perspectives
 Describing things in the domain of interest
 Specification Perspectives
 Describing software abstractions, but no commitment to a
particular implementation
 Implementation Perspectives
 Describing implementations in a particular technology
Three ways to apply UML and Three perspectives to apply UML

Three perspectives to apply UML

UML Diagrams
 Static diagrams (Structural Diagram)
 Class Diagram
 Object Diagram
 Component Diagram
 Deployment Diagram
 Package Diagram
 Behaviour diagrams
 Use case Diagram
 Activity Diagram
 Interaction Diagram
 Sequence Diagram
 Collaboration Diagram
 State Chart Diagram

Usecase Diagram:
Use case diagram shows an interaction between users (Actors) and system
Usecase - Scenarios in which your system or application interacts with people,
organizations, or external systems

Example use case diagram for passport automation system
submit details
applicant
check status
regional
administrator
issue passport
passport
administrator
login
get details
verify
police
store verification

Class Diagram:
Class Diagram gives the static view of an application.
A class can refer to another class. A class can have its objects or may inherit from
other classes.
UML Class Diagram gives an overview of a software system by displaying classes,
attributes, operations, and their relationships.
This Diagram includes the class name, attributes, and operation in separate designated
compartments.

Example Class Diagram for passport automation system

Object Diagram
Object diagrams are derived from class diagrams so object diagrams are
dependent upon class diagrams.
Object diagrams represent an instance of a class diagram.
Object diagrams also represent the static view of a system but this static view is a
snapshot of the system at a particular moment

Activity Diagram:
Activity diagram describe the dynamic aspects of the system. Activity diagram is
basically a flowchart to represent the flow from one activity to another activity.

Example activity diagram for passport automation system
login
submit
details
get details
verification
penalty as
per law
issue
passport

Example activity diagram for passport automation system

Sequence Diagram: (Interaction Diagram)
Sequence Diagrams depicts interaction between objects in a sequential order i.e. the
order in which these interactions take place
It shows timeline which show the order of the interaction visually by using the vertical
axis of the diagram to represent time what messages are sent and when.

Example sequence diagram for passport automation system
applicant passport
administrator
regional
administrator
police database
1: login
2: give details
3: store the details
4: verify the details
5: update the details
6: send details
7: verify details
8: send verification
10: send details
14: issue passport

Collaboration Diagram (Interaction Diagram)
A collaboration diagram is a type of interaction diagram that shows how various
software objects interact with each other within an overall IT architecture and how
users can benefit from this collaboration. It shows clear view of interaction between
objects. Messages are sequentially numbered. Its generated from sequence diagram

Example collboration diagram for passport automation system
applican
t
passport
administrator
regional
administrator
police
databas
e
7: verify details
1: login
2: give details
14: issue passport
3: store the details
6: send details
10: send details

State Chart Diagram
State chart Diagram describes different states of a component in a system. The
states are specific to a component/object of a system. It describes state machine.
It models dynamic behaviour of class.

Example state chart diagram for passport automation system
login give
details
get
details
verificati
on
issue

Component Diagram
Component diagram is to show the relationship between different components in a
system.
It model the physical aspects of a system. Physical aspects are the elements such as
executables, libraries, files, documents, etc. which reside in a node.

Example component diagram for passport automation system
PASSPORT
AUTOMATION
APPLICANT
PASSPORT
ADMINISTRATOR
REGIONAL
ADMINISTRATOR
POLICE

Deployment Diagram
Deployment diagrams are used to visualize the topology of the physical components of a
system, where the software components are deployed.
Deployment diagrams are used to describe the static deployment view of a system.
Deployment diagrams consist of nodes and their relationships

Example deployment diagram for passport automation system
passport automation
system
applicant passport
administrator
regional
administrator
police

Package Diagram
Package diagrams are used to structure high level system elements.
Packages are used for organizing large system which contains
diagrams, documents and other key deliverables.
Package Diagram can be used to simplify complex class diagrams, it
can group classes into packages.

Example package diagram for passport automation system
web
applicant passport
administrator
police
regional
administrator
DOMAIN
give and get
details
verification
issue
technical details
login database1

Case study: Hospital management system
A system to manage the activities in a hospital:
Patients request for appointment for any doctor. The details of the
existing patients are retrieved by the system. New patients update
their details in the system before they request for appointment with
the help of assistant. The assistant confirms the appointment based
on the availability of free slots for the respective doctors and the
patient is informed. Assistant may cancel the appointment at any
time.
Construct Actors, Use cases, class diagram, Sequence
Diagram and state chart diagram.

Case Study: The NextGen POS System
• A POS system is a computerized application used
to record sales and handle payments;
• it is typically used in a retail store.
• It includes hardware components such as a
computer and bar code scanner, and software to run
the system.
• It interfaces to various service applications, such as
a third-party tax calculator and inventory control.

• These systems must be relatively fault-tolerant. That is, even if remote
services are temporarily unavailable (such as the inventory system), they
must still be capable of capturing sales and handling at least cash
payments.
• A POS system must support multiple and varied client-side terminals and
interfaces. These include a thin-client Web browser terminal, a regular
personal computer with something like a Java Swing graphical user
interface, touch screen input, wireless PDAs, and so forth.
• we are creating a commercial POS system that we will sell to different
clients with disparate needs in terms of business rule processing.
Therefore, we will need a mechanism to provide this flexibility and
customization.
• Using an iterative development strategy, we are going to proceed through
requirements, object-oriented analysis, design, and implementation.
Case Study: The NextGen POS System (Contd.)

Logging Database Access
User
interface
Application
Logic and
Domain object
layer
Technical
Services layer
minor focus
Explore how to
connect to
other layers
Primary focus of
case study
Explore how to
design objects
Sale Payment
Secondary focus
Explore how to
design objects
Item ID
Quantity
Case Study: The NextGen POS System (Contd.)

Use Case Modelling
 Use Case Model describes the proposed functionality of the new system. It is a
pictorial representation of interaction between user and system.(Usecase
Diagram)
 Use Case represents a discrete unit of interaction between a user (human or
machine) and the system. Example :login to system, register with system and
create order are all Use Cases. It is also called scenarios.
 Each Use Case has a description which describes the functionality that will be
built in the proposed system.
 A Use Case may 'include' another Use Case's functionality or 'extend' another
Use Case with its own behavior.
 Use Cases are typically related to 'actors'. An actor is a human or machine entity
that interacts with the system to perform meaningful work.
 Actors An Actor is a user of the system. This includes both human users and
other computer systems. An Actor uses a Use Case to perform some piece of
work which is of value to the business.

Use Case Modelling (Contd.)
Components of Use case Diagrams
 Use cases: A use case describes a sequence of actions
that provide something of measurable value to an
actor and is drawn as a horizontal ellipse.
 Actors: An actor is a person, organization, or external
system that plays a role in one or more interactions
with your system. Actors are drawn as stick figures.
 Associations: Associations between actors and use
cases are indicated by solid lines. An association
exists whenever an actor is involved with an
interaction described by a use case.

Notations

Actors
• An actor models an external entity which communicates
with the system:
– User
– External system
– Physical environment
• An actor has a unique name and an optional description.
• Examples:
– Passenger: A person in the train
– GPS satellite: Provides the system with GPS coordinates
Passenger

Use Case
• A use case represents a class of functionality provided by
the system as an event flow.
A use case consists of:
• Unique name
• Participating actors
• Entry conditions
• Flow of events
• Exit conditions
• Special requirements
PurchaseTicket

Example :Use case Modelling – NextGenPOS System

Example :Use case Modelling – NextGenPOS
System

Use case Modelling
Use Case: Process Sales
 Customer arrives at POS checkout with goods to purchase.
 Cashier starts a new sale.
 Cashier enters item identifier.
 System records sale line item and presents item description, price, and
running total. Price calculated from a set of price rules.
 Cashier repeats step 3-4 until done with all items.
 System presents total with taxes calculated.
 Cashier tells Customer the total, and asks for payment.
 Customer pays and System handles payment.
 System logs completed sale and sends sale and payment information to
the external Accounting system (for accounting and commissions) and
Inventory system (to update inventory).
 System presents receipt.
 Customer leaves with receipt and goods.

Relating Use Cases
There are three other types of relationship
between usecases.
 Extends
 Includes
 Generalization

<<extends>> Association (Relationship)
• <<extends>> relationship
represent exceptional or
seldom invoked cases.
• The exceptional event
flows are factored out of
the main event flow for
clarity.
• Use cases representing
exceptional flows can
extend more than one use
case.
• The direction of a
<<extends>> relationship is
to the extended use case

<<includes>>Association(Relationship) or
<<uses>> relationship
• <<includes>> relationship
represents behavior that
is factored out of the use
case.
• <<includes>> behavior is
factored out for reuse,
not because it is an
exception.
• The direction of a
<<includes>> relationship
is to the using use case
(unlike <<extends>>
relationships).

Generalization relationship
 Use case generalization can be used when one use case that is similar to
another, but does something slightly differently or something more.
 Generalization works the same way with use cases as it does with
classes.
 The child use case inherits the behavior and meaning of the parent use
case.
 Base and the derived use cases are separate use cases and should have
separate text descriptions
 Represented by a line and a hollow arrow from child to parent
Child use case Parent use case

Applications
 Software development
 Solving any real world problems
 Understanding the essential requirements of the
customer to ss.atisfy their business need

UNIT-I(Unified_Process_and_Use Case_Diagrams)_OOAD.ppt

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