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Object Oriented Analysis and Design Using UML

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Course description:

OBJECTIVE:

The understand the Unified Modeling Language and orient towards Object Oriented methodology using UML for modeling software systems.

TARGET AUDIENCE:

In particular, it is intended for software professionals who have sound knowledge of object concepts and some experience towards analysis and design.

PREREQUISITES:

Good understanding of object concepts.

Sound knowledge of any object oriented language.

Knowledge of software engineering process.

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Course description:

TABLE OF CONTENTS:

Module1 Introduction

Module2 Use case diagram

Module3 Flow of events

Module 4 Realization of the class diagramSequence diagram and Collaboration Diagram

Module5 Class diagram and refinement attributes

Module6 State transition and activity diagram

Module7 Implementation diagram

Component diagram and Deployment diagram

Module8 Understanding project culture

Appendix-A

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Module-1

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Importance of modeling

What is a model?– A model is a simplification of reality

Why do we model?– help visualizing– permit specification– provides a template– document decisions

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4 Principles of Modeling

Choose your models well Every model may be expressed at various

levels of precision The best models are connected to reality No single model is sufficient

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What is Software Engineering?

DEFINITION:The application of systematic, disciplined and qualifiable approach to the development, operation and maintenance of a software system is software engineering.

Software development life cycle has following stages:

REQUIREMENT

ANALYSIS

DESIGN

IMPLEMENTATION

TESTING

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Effort Distribution for each stage:

Analysis & design 40 %Development 20 %Testing 40 %

Analysis - What is to be done ? Design - How it is to be done ?

Two Popular methodology approaches are:

Structured Analysis & Design Object Oriented Analysis & Design-OO model

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Major benefits of OOAD:

The object oriented approach is a way of thinking about a problem using real world concepts instead using adhoc function concepts.

We intent to learn OOAD approach for the following reason:–Promotes better understanding of user requirements–Leads cleaner design–Design flexibility'–Decomposition of the system is consistent–Facilitates data abstraction & information hiding–Software reuse–Easy maintenance–Implementation flexibility

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Elements of OO Methodology:

Following are three elements for every OO methodology:

Notation Process / Method Tool

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What is Notation?

Notation:

It is collection of graphical symbols for expressing model of the

system.

The Unified Modeling Language [UML] provides a very robust set

of notation which grows from analysis to design.

This brings end of the method wars as far as notation is concerned

with adoption of the language [UML]

By unifying the notations used by these object oriented methods, the unified modeling language provides the basis for a de facto standard in the domain of object oriented analysis and design founded on a wide base of user experience

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What is UML?

It is a Unified Modeling Language, which is mainly a collection of graphical notation that methods use to express the designs.

The UML is language for visualizing, specifying, constructing and documenting the artifacts of software system.

UML is visual modeling language for modeling systems and is non proprietary

UML is not a radical departure from Booch, OMT, OOSE notations but rather legitimate successor to all three.

It is an evolutionary step, which is more expressive and more uniform than individual notations.

Whitehead says “ By relieving the brain of unnecessary work, a good notation, sets it

free to concentrate on more advance and creative problems “ UML is not a method or process but is the means to express the same.

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Where can you use the UML?

System of several different kinds, absolutely anywhere everywhere. Primarily for software intensive systems like:

Systems software

Business processes

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The Evolution of the UML:

UML1.1

UML1.0

UML0.9

Beta version OOPSLA’96

Public Feedback

Submission of OMG group

OMG vote’97Submission to OMG, sept’97

Unified Method 0.8

Other method Booch OMT OOSE

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Advantages of UML:

Captures business processes

Enhance communication and ensures the right communication

Capability to capture the logical software architecture independent of the implementation language

Manages the complexity

Enables reuse of design

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UML refers to:

UML things:

Class, component, node, relationship, package etc..

UML diagrams:

Use case diagram, interaction diagram, class diagram, State diagram,deployment diagram

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What is Process?

What is Process?

It is an extensive set of guidelines that address the technical and organizational aspects of software development focusing on requirements, analysis and design.

Process basically encapsulates the activities leading to the orderly construction of system model.

OO model supports the iterative and incremental model for the process.

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More about Process?

Guidance as to the order of team’s activities It specifies what artifacts should be developed It directs the task of individual developers and team as a whole It offers criteria for monitoring and measuring project activities The selection of particular process will vary greatly depending upon

things like problem domain, implementation technology and skills of team

Booch,OMT,OOSE and many other methods have well defined process and UML supports almost all methods

There has been some convergence on development process practices but there is no consensus for standardization.

Framework for the every stage of software development life cycle.

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Best Practices followed by Rational Unified Process

Develop software iteratively Manage requirements Use component based architectures Visually model software Verify S/W quality Control changes to software.

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What is a tool?

It is automated support for every stage of software developmentlife cycle.

Since we are concentrating on requirement, analysis and design phase, following are the names of few tools which are greatly in use:

1. Rational Rose2. Cayenne3. Platinum4. Select

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Why Tool?

Helps designer for creating designs much more quickly. Supports validations like:

Consistency checking

Completeness checking

Constrain checking. Time required for certain operation could be predicted . Code generation Reverse engineering. Round trip engineering Conversion from SSAD to OOAD Quick documentation…etc

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Triangle for Success:

All three components play equally important role towards the success of the project.

Notation

MethodTool

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Objective of the first module:

Get introduced with Unified Modeling Language and know the basic components of software development life cycle.

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Module-2

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OO model:

STATIC MODEL

DYNAMIC MODEL

PHYSICAL MODEL

LOGICAL MODEL

The models of Object Oriented Development

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Models and Views:

4+1 view of OO model.– Process view

– Deployment view

– Logical view

– Dynamic view

+

– Use case view

As shown in the model , for each dimension we define a number of diagrams that denote a view of the system’s model.

The use case view is central since its contents drive the developments of other views.

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UML diagrams:

1. Use case diagram2. Class Diagram3. Behavioral diagrams

- State chart diagrams- Object diagram

- Activity diagrams- Interaction diagrams

- Sequence diagrams- Collaboration diagrams

4. Implementation diagrams- Component diagram- Deployment diagram

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Semantics of Diagrams:

Use case diagrams represent the functions of a system from the user’s point of view.

Sequence diagrams are a temporal representation of objects and their interactions.

Collaboration diagrams are a spatial representation of objects, links, and interactions.

Object diagrams represent objects and their relationships, and correspond to simplified collaboration diagrams that do not represent message broadcasts.

Class diagrams represent the static structure in terms of classes and relationships.

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Semantics of Diagrams:

Contd... State chart diagrams represent the behavior of a class in terms of states Activity diagrams are to represent the parallel behavior of an operation

as a set of actions. Component diagrams represent the logical components of an

application. Deployment diagrams represent the deployment of components on

particular pieces of hardware.

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What is USE CASE diagram?

A use case diagram establish the capability of the system as a whole.

Components of use case diagram:

Actor

Use case

System boundary

Relationship

Actor relationship

Semantic of the components is followed.

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ACTOR:

What is an actor?

An actor is some one or something that must interact with the system under development

UML notation for actor is stickman, shown below.

Customer Manager Cashier

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ACTOR:

More about an actor:

It is role a user plays with respect to system. Actors are not part of the system they represent anyone or

anything that must interact with the system. Actors carry out use cases and a single actor may perform more

than one use cases. Actors are determined by observing the direct uses of the

system,

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ACTOR:

Contd…

Those are responsible for its use and maintain as well as other systems that interact with the developed system.

An actor may

- input information to the system.

- receive information from the system.

- input to and out from the system.

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ACTOR:

How do we find the actor?

Ask following questions to find the actors:– Who uses the system?

– Who installs the system?

– Who Starts up the system?

– What other systems use this system?

– Who gets the information from the system?

– Who provides information to the system?

Actor is always external to the system. They are never part of the

system to be developed.

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ACTOR:

4-Categories of an actor:

Principle : Who uses the main system functions. Secondary : Who takes care of administration & maintenance. External h/w : The h/w devices which are part of application

domain and must be used. Other system: The other system with which the system must

interact.

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ACTOR:

Note:

If newly identified actor is using a system in a same way like an

existing actor, then new actor can be dropped. If two actors use system in the same way they are same actors.

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USE CASE:

What is USE case? A use case is a pattern of behavior, the system exhibits Each use case is a sequence of related transactions performed by an

actor and the system in dialogue. USE CASE is dialogue between an actor and the system. Examples:

Open new account Withdrawal of cash from ATM

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USE CASE:

More about USE CASE:

It is a snapshot of one aspect of system. They model a dialog between actor and system. A use case typically represents a major piece of functionality

that is complete from beginning to end. Most of the use cases are generated in initial phase, but you

find some more as you proceed. A use case may be small or large. It captures a broad view of a

primary functionality of the system in a manner that can be easily grasped by non technical user.

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USE CASE:

Contd…

A use case must deliver something of value to an actor. The use cases may be decomposed into other use cases. Use cases also present a good vehicle for project planning.

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USE CASE:

How do we find the use cases?

What functions will the actor want from the system? Does the system store information? What actors will create, read,

update. Or delete that information? Does the system need to notify an actor about changes in its internal

state?

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USE CASE:

Generic format for documenting the use case:

- Pre condition: If any– Use case : Name of the case.

– Actors : List of actors(external agents), indicating who initiates the use case.

– Purpose : Intention of the use case.

– Overview : Description.

– Type : primary / secondary.

– Post condition: If any Typical Course of Events:

ACTOR ACTION : Numbered actions of the actor.

SYSTEM RESPONSE : Numbered description of system responses.

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USE CASE:

USE CASE documentation example: The following use case describes the process of opening a new

account in the bank.

Use case :Open new account

Actors :Customer, Cashier, Manager

Purpose :Like to have new saving account.

Description :A customer arrives in the bank to open the new

account. Customer requests for the new account

form, fill the same and submits, along with the

minimal deposit. At the end of complete successful

process customer receives the passbook.

Type :Primary use case.

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Grouping USE CASES:

Those use case functionality which are directly dependent on the system environment are placed in interface objects

Those functionality dealing with storage and handling of information are placed in entity objects

Functionality's specific to one or few use cases and not naturally placed in any of the other objects are placed in control objects

By performing this division we obtain a structure which helps us to understand the system from logical view

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OOAD --- USE CASE driven

Capture,clarify& validate use cases

Analysis Design &Implementation

Implement use cases

Use cases make up the glue

Test

Verify that use cases are satisfied

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SYSTEM BOUNDARY:

What is System Boundary?

It is shown as a rectangle. It helps to identify what is external verses internal, and what the

responsibilities of the system are. The external environment is represented only by actors.

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RELATIONSHIP:

What is Relationship?

Relationship between use case and actor.

Communicates Relationship between two use cases

Extends

Uses Notation used to show the relationships:

<< >>

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RELATIONSHIP:

Relationship between use case and actor is often referred as “communicates” .

Relationship between two use cases is refereed as either uses or extends.

USES: - Multiple use cases share a piece of same functionality. - This functionality is placed in a separate use case rather than

documenting in every use case that needs it.

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RELATIONSHIP:

Contd... A uses relationship shows behavior that is common to one or

more use cases.

EXTENDS: It is used to show optional behavior, which is required only

under certain condition.

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USE CASE diagram:

Use case diagram for the shown functionality.

Balance status report

Withdraw cash

Validation

uses

CustomerClerk

Manager

extends

ATM

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Objective of the second module

To understand and capture the detailed specification of a system to be developed, from user perspective.

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Module-3

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Beginning Analysis and Design

Completion of first version of use case diagram initiates the processes of analysis and design.

UML provides the framework to carry out the process of analysis and design in form of set of diagrams.

Every diagram and notation used in the diagram carries the semantics. First step towards analysis and design is to specify the flow of events.

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Flow of Events:

A flow of events document is created for each use case. Details about what the system must provide to the actor when the use

is executed. Typical contents

– How the use case starts and ends– Normal flow of events– Alternate flow of events– Exceptional flow of events

Typical Course of Events has:

Actor Action(AA)

System Response(SR)

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Normal Flow of Events:

For withdrawal of cash:

1.(SR) The ATM asks the user to insert a card. 2.(AA) The user inserts a cash card. 3.(SR) The ATM accepts the card and reads its serial number. 4.(SR) The ATM requests the password. 5.(AA) The user enters 1234. 6.(SR) The ATM verifies the serial number and password with the

bank and gets the notification accordingly. 7.(SA)The ATM asks the user to select the kind of transaction. 8.(AA)User selects the withdrawal.

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Normal Flow of Events:

Contd... 9.(SR)The ATM asks for the amount of cash; user enters Rs. 2500/- 10.(SR)The ATM verifies that the amount of cash is within predefined

policy limits and asks the bank, to process the transaction which eventually confirms success and returns the new account balance.

11.(SR) The ATM dispenses cash and asks the user to take it. 12.(AA) The user takes the cash. 13.(SR) The ATM asks whether the user wants to continue. 14.(AA) The user indicates no.

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Normal Flow of Events:

Contd... 15.(SR) The ATM prints a receipt, ejects the card and asks the user to

take them 16.(AA) The user takes the receipt and the card. 17.(SR) The ATM asks a user to insert a card.

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Alternative Flow of Events:

For withdrawal of cash use case: 9. The ATM asks for the amount of cash; the user has change of mind

and hits the “cancel”.

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Exceptional Flow of Events:

For withdrawal of cash use case: 3 Suspicious pattern of usage on the card. 10 The machine is out of cash. 11 Money gets stuck in the machine.

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Why flow of events?

It helps in understanding the functionality of a system to be developed. Flow of events helps in finding objects of the system to be developed. Happens to be most important and very first step towards analysis and

design.

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What is Scenario?

The functionality of the use case is captured in flow of the

events. A scenarios is one path through the flow of events for the use

case. Scenarios are developed to help identify objects, classes and

object interactions for that use case.

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Objective of the third module

To understand the flow of each functionality and find out the objects and methods required to build the system.

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Module-4

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USE CASE Realizations:

The use case diagram presents an outside view of the system Interaction diagrams describe how use cases are realized as

interactions among societies of objects. Two types of interaction diagrams

– Sequence diagrams

– Collaboration diagrams

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What is Interaction diagram?

Interaction diagrams are models that describe how groups of objects collaborate in some behavior

There are 2 kinds of interaction diagrams

• Sequence diagram

• Collaboration diagram Sequence diagrams are a temporal representation of objects and their

interactions Collaboration diagrams are spatial representation of objects, links and

interrelations

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What is sequence diagram?

Typically these diagrams capture behaviors of the single scenario.

Shows object interaction arranged in time sequence. They show sequence of messages among the objects. It has two dimensions, vertical represents time & horizontal represents objects. Components of sequence diagram:

-objects

-object lifeline

-Message

-pre/post conditions.

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OBJECT & OBJECT LIFE LINE:

Object are represented by rectangles and name of the objects are underlined. Object life line are denoted as dashed lines. They are used to model the existence of objects over time.

Name:Class

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MESSAGES:

They are used to model the content of communication between objects. They are used to convey information between objects and enable objects to request services of other objects.

The message instance has a sender, receiver, and possibly other information according to the characteristics of the request.

Messages are denoted as labeled horizontal arrows between life lines.

The sender will send the message and receiver will receive the message.

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MESSAGES:

Contd… May have square brackets containing a guard conditions. This is a

Boolean condition that must be satisfied to enable the message to be sent.

May have have an asterisk followed by square brackets containing an iteration specification. This specifies the number of times the message is sent.

May have return list consisting of a comma -separated list of names that designate the values of returned by the operation.

Must have a name or identifier string that represents the message. May have parentheses containing an argument list consisting of a

comma separated list of actual parameters passed to a method.

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:Customer :ATM :BankRequest password

Verify accountEnter the password

Account o.k.Request option

Enter option

Request amount

Enter the amountUpdate transaction

Transaction commit

Insert card

Dispense cash

Request take cash

Take cash

Request continuation

Terminate

Print receipt ,eject card

Request take cardTake card

Display main screen and prompt for the card.

:TransactionCreate Transaction

Transaction complete

Sequence diagram [for withdrawal of cash, normal flow]

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What is Collaboration diagram?

Collaboration diagrams illustrate the interaction between the objects, using static spatial structure.

Unlike sequence diagram the time is not explicitly represented in these diagrams

In collaboration diagram the sequence of messages is indicated by numbering the messages. The UML uses the decimal numbering scheme.

In these diagrams, an actor can be displayed in order to represent the triggering of interaction by an element external to the system.

This helps in representing the interaction, without going into the details of user interface.

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Components of collaboration diagram:

Named objects Links: Links are represented by a continuous line between objects, and

indicates the exchange of messages. Messages has following attributes:

• Synchronization --thread name, step within thread.

• Sequence number

• Message labels : The name of the message often corresponds to an operation defined in the class of the object that is the destination of the message. Message names may have the arguments and return values.

• *[iteration].

• It uses decimal notation.

• Message direction.

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Semantics of components:

Object names identify which objects are participating and the links show which objects collaborate

A link between two objects must exist for one object to send message to another and vice a versa.

Messages in the collaboration diagram get transformed to more detailed signature.

They use the decimal notation system for numbering the messages. The direction of the message defines the sender and receiver of

the message

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The elements of message:

Predecessor Role names Message qualifiers

– Iteration expression

– Parameters

– Return values

– Guard

– Message stereotypes

Concurrent thread sequencing Thread dependencies Message expression

[Pre] A1:*(expression):doIt(p,r):return value

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The examples of message:

4:Display(x,y) Simplemessage

3.3.1:Display(x,y) Nestedmessage

4.2:subtract[Today,Birthday]:age Nestedmessage withreturn value

[Age >=18] 6.2:Vote() Conditionalmessage

4.a,b.6/c.1:Turnon(Lamp) Synchro. withother flow ofexecution

1*:wash() Iteration

3.a,3.b/4*||[i:=1..n]:Turnoff() Paralleliteration

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Collaboration diagram [for withdrawal of cash, normal flow.]

1. Insert cardEnter password, Enter kindEnter amount,Take cash, Take cardcancel,Terminate, Continue

Display main screen unreadable card message,request password,request kind, request amount,canceled message, eject card, failure message,dispense cash, request take cashrequest continuation,print receipt, request take cardbad account message,bad bank account message

Verify account,process transaction

Transaction succeedTransaction failedaccount o.k.bad account,bad password,bad bank code

Create TransactionTransaction completeCUST-

OMER

BANK

ATMTRANSA-CTION

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Objective of the fifth module

To know the interaction among the objects in temporal and spatial form.

To know how objects collaborate among each other and hence delegate the responsibility to the respective objects.

To understand how the messages get matured with more information.

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Module-5

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What is Class diagram?

A class diagram shows the existence of classes and their relationships in the logical view of a system

UML modeling elements in class diagrams are:– Classes, their structure and behavior.– relationships components among the classes like association,

aggregation, composition, dependency and inheritance– Multiplicity and navigation indicators– Role names or labels.

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Major Types of classes:

Concrete classes A concrete class is a class that is instantiable; that is it can have

different instances. Only concrete classes may be leaf classes in the inheritance tree.

Abstract classes An abstract class is a class that has no direct instance but whose

descendants classes have direct instances. An abstract class can define the protocol for an operation without

supplying a corresponding method we call this as an abstract operation.

An abstract operation defines the form of operation, for which each concrete subclass should provide its own implementation.

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RELATIONSHIP:

Association Aggregation Composition Inheritance Dependency Instantiation

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ASSOCIATION:

These are the most general type of relationship: It denotes a semantic connection between two classes It shows BI directional connection between two classes It is a weak coupling as associated classes remain somewhat

independent of each other Example:

CUSTOMERATM system

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AGGREGATION:

This is a special type of association The association with label “contains” or “is part of” is an

aggregation It represents “has a “ relationship It is used when one object logically or physically contains other The container is called as aggregate It has a diamond at its end The components of aggregate can be shared with others It expresses a whole - part relationships

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AGGREGATION:

Example:

Customer ATM card

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COMPOSITION:

This is a strong form of aggregation It expresses the stronger coupling between the classes The owner is explicitly responsible for creation and deletion of

the part Any deletion of whole is considered to cascade its part The aggregate has a filled diamond at its end

Window Client Area

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INHERITANCE:

The inheritance relationship helps in managing the complexity by ordering objects within trees of classes with increasing levels of abstraction. Notation used is solid line with arrowhead,shown below.

Generalization and specialization are points of view that are based on inheritance hierarchies.

Account

SavingAccountCurrentAccount

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DEPENDENCY:

Dependency is semantic connection between dependent and independent model elements.

This association is unidirectional and is shown with dotted arrowhead line.

In the following example it shows the dependency relationship between client and server.

The client avails services provided by server so it should have semantic knowledge of server.

The server need not know about client.

Client Server

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INSTANTIATION

This relationship is defined between parameterized class and actual class.

Parameterized class is also referred as generic class. A parameterized class can’t have instances unless we first

instantiated it

Example:

Queue<int>

Queue

Element

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What is Cardinality? :

Definition: Number of instances of each class involved in the dialogue is specified by cardinality.

Common multiplicity values: Symbol Meaning 1 One and only one 0..1 Zero or one M…N From M to N (natural integer) 0..* From zero to any positive integer 1..* From one to any positive integer

Also thought can be given about navigability to every applicable relationship.

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Reaching the class diagram:

In collaboration diagram we have shown the objects, their interaction and detailed message signature.

This information is carried forward to the class diagram. At this point,we group the similar objects and form classes. Messages get mapped to responsibilities for respective classes. Find the attributes for every class. Transform the links to appropriate relationships. Relationship is further refined with respect to multiplicity and

navigability.

This complete procedure brings the minimal class diagram [for withdraw cash use case, normal flow.]

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Class diagram [for withdrawal of cash, normal flow]

Customer

Transaction

1

0..*

1

0..*ATMSystem

1..*

1..*

1..*

1..*

Bank[Branch]1

1..*

1

1..* 11

11

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What more to the Class Diagram?

Till this slide we have worked out the essentials of class diagram for withdrawal of cash use case, normal flow of events.

Similar exercise required to be carried out for every scenario and clubbed all in the class diagram.

At this point, we refine this integrated class diagram to add further fine details. Approximate sketch for this class diagram has been shown at the end of this module.

Refinement attributes should be updated right from sequence diagram to class diagram.

Next few slides will take into the discussion of refinement attributes. This process of iterative and incremental development will continue

till there is no change in two consecutive iteration.

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OOAD---Iterative & Incremental Approach

Identify objects

Identify Messages

Group Objects into classes

Identify & classifyClass relationshipsIdentify class

behavior

Group classesinto domains

Validate Classes& Objects

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Refinement attributes:

Stereotypes:

Stereotypes are part of the range of extensibility mechanism provided by UML

It permits user to add new model element classes on top of the kernel predefined by UML

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Refinement attributes:

Contd…

Constraints: Constraints are functional relationship between the entities and object

model. The entities include objects, classes, attributes, association, links.

A constraint restricts the values that entities can assume. UML doesn't specify a particular syntax for constraints, other than

they should appear between braces, so they may therefore be expressed using natural language, pseudo code, navigation expression or mathematical expression

UML1.2 does prefer the use of a constraint language OCL i.e. Object Constraint Language, which is subset of UML.

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Refinement attributes:

Transaction

Windowlength/width

{No. of transaction <=5 /day}

{0.8<=length/width <= 1.5}

Constraint on the same class.

A constraint between the properties of the same object

No window will have an aspect ratio i.e. (length/width) of less than 0.8 or > 1.5

Number of withdrawal transaction should be less than five per day.Example:Constraints

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Refinement attributes:

Qualifier: UML provides a role of constraint notation to indicate different kind

of collections that may be inherent in the analysis model

Common role constraints for multi valued roles include {ordered} Collection is maintained in sorted manner

{bag} Collection may have multiple copies of same item.

{set} Collection may have at most one copy of given item.

Some constraints may be combined such as: {ordered set}

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Refinement attributes:

Qualifier: Another common design scheme is to use a key value to retrieve an

item from the collection. This is called as qualified association and the key value as qualifier.

A qualified association is the UML equivalent of a programming concept variously known as associative arrays, maps,dictionaries

A qualified association relates two object classes and a qualifier The qualifier is a special attribute that reduced the effective

multiplicity of an association.

One to many and many to many association may be qualified.

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Refinement attributes:

Check for many to many relationship, if any, normalize with qualifier or association class.

Check for the scope forming abstract classes and template classes. Check for helper functions. Thought can be given for using the design patterns.

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Objective of the fifth module:

Learn to build the architecture, which contains the entire information of the system to be developed.

It is this architecture which is called as BLUE PRINT is handed over for coding.

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Refined Class diagram [for withdrawal of cash]

SavingAccount

AccountAccessor<<abstract>>

TellerScreen

ATMScreenBankAssociates

CashierStation

person<<abstract>>

Cash

BatchJob

NoteHelpForBankCard

ATMSystem

BankComputer

Area

BankCard

Bank[Branch]11

1..*1..*

Customer

1

0..1

1

0..1

11

Account<<abstract>>

1

1

1

1

1..*

1

1..*

1

Transaction

11..*

11..*

Slips

CurrentAccount

Few more relationship can be further added to the shown diagram:

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Module-6

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What is state transition diagram?

A state transition diagram shows the states of a single object, the events or the messages that cause a transition from one state to another and the action that result from a state change.

A state transition diagram will not be created for every class in the system.

Components of State Diagram:– Start State

– Stop state

– State Transition

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Semantics of every components:

State: A state is a condition during the life of an object when it satisfies some condition, performs some action, or waits for an event.

The UML notation for a state is a rectangle with rounded corners.

Special states:There are two special states.

Start state: Each state diagram must have one and only one start

state. Notation for start state is “filled solid circle”.

Stop State: An object can have multiple stop states. Notation for stop

state is bull’s eye.

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Semantics of every components:

Contd... State transition: A state transition represents a change from an

originating to a successor state. Transition label: event name[guard condition] / action

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State Transition Diagram [for Account class. ]

Operational

Dormant

Open

seized

transaction request[ validate ] / update()

close

no transaction / Transfer_to_Dormant_Ledger

fill_the_request_form / update()

Fraud or authorized instruction[Validate] / lockAccount()

matter_resolved[ validate ] / unlockAccount()

request and fill the form for new saving account[ validate ] / process

fill_the_request_form/update()

transactionStrart / Transfer_to_main_ledger ()

Note:Account can be closed from open state as well

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More about State Diagram:

A state diagram will not be created for every class. state diagrams are used only for those classes that exhibit interesting

behavior. State diagrams are also useful to investigate the behavior of user

interface and control classes. State diagram are used to show dynamics of a individual class

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What is activity diagram?

It is a special kind of state diagram and is worked out at use case level. These are mainly targeted towards representing internal behavior of a

a use case. These may be thought as a kind of flowchart. Flowcharts are normally limited to sequential process; activity

diagrams can handle parallel process. Activity diagrams are recommended in the following situations:

Analyzing use case Dealing with multithreaded application Understanding workflow across many

use cases.

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Consistency Checking

Consistency checking is the process of ensuring that, information in both static view of the system(class diagram) and the dynamic view of the system(sequence and collaboration diagram) is telling the same story.

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Objective of the sixth module

Understand the dynamic behavior of a class

Way to find the parallel processes at use case level.

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Module-7

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What is component diagram?

COMPONENT DIAGRAM:

Component diagrams illustrate the organizations and dependencies among software components.

A component may be

• A source code component

• A run time components

• An executable component

• Dependency relationship.

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Component Diagram [for withdrawal of cash]

policy.dll

BranchBank.dllcustomer.dll

ATM.exe

BranchBank.exe

BankServer.exe

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What is deployment diagram?

A deployment diagram shows the relationship among software and hardware components in the delivered system.

These diagram include nodes and connections between nodes. Each node in deployment diagram represents some kind of

computational unit, in most cases a piece of hardware. Connection among nodes show the communication path over which

the system will interact. The connections may represent direct hardware coupling line RS-232

cable, Ethernet connection, they also may represent indirect coupling such as satellite to ground communication.

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Deployment diagram

ATM_machine

Bank_server

BranchBank_

EthernetEthernet

Bank.exe

BankServer.exeATM.exe

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Objective of the seventh module:

To understand the organization of software modules and their deployment on the respective hardware.

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Module-8

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Understanding the project culture

It may be:

1.Calendar Centric

2.Requirement Centric

3.Documentation Centric

4.Quality Centric

5.Architecture Centric

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Understanding the project’s culture

Architecture driven projects represent the most mature style of development.

These projects are characterized by a focus on creating a frame work that satisfies all known requirement, yet is resilient enough to adapt to those requirements, that are not yet known or well understood.

In every sense of the word, architect-driven policies are in evolutionary step beyond requirement driven policies.

Architecture driven style of development is usually the best approach for the creation of most complex software intensive systems

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Understanding the project’s culture

Architecture driven style of development typically observe the following process:

1. Specify the system’s desired behavior through a collection of

scenarios. (Analysis)

2. Create, then validate, an architecture. (Design)

3. Evolve that architecture, making mid-course corrections as

necessary to adopt to new requirements as they are uncovered.

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OOAD---Architecture Centric

What exactly is nature of the well structured object oriented architecture??

1. A set of classes, typically organized into multiple hierarchies.

2. A set of collaboration that specify how those classes co-operate

to provide various system function.

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ESSENCE OF OOAD AND UML

Use case driven

Architecture centric

Incremental and iterative approach.

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Desire for good Architecture

Those of us who have been trained as architects have this desire perhaps at the very center of our lives,that one day, some where somehow, we shall build one building which is wonderful, beautiful, breathtaking, a place where people can walk and dream for centuries.

CHRISTOPHER ALEXANDER

Same desire should also be applicable in creating software architecture as well.

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Appendix-A

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Object Technology – David A. Taylor

Object Oriented Analysis and design with Applications – Grady Booch

UML distilled –Martin Fowler

Instant UML – Pierre - Alain Muller

Software Engineering – Roger S Pressman

Strong recommendation

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REFERENCES

Contd...Object Oriented Modeling and Design – James Rumbaugh

Object Oriented Software Engineering– Ivar Jacobson

Clouds to code – Jesse LibertyApplying use cases

– Geri Schneider

–Jason p. WintersUML Toolkit

– Hans-Eriksson and Magnus Penker Version1.1

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THANK-U!

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Course description:

SESSION BREAKUP:

The course will be offered in series of fourteen hours theory session. One demonstration session on the tool like Rational Rose can be accompanied.The following is the suggested agenda for the course.

Session Duration

Module-1,2 2-hours demonstration lecture

Module-3 2-hours

Module-4 2-hours

Module-5 4-hours

Module-6 2-hours

Module-7,8 2-hours

Demonstration 2-hours

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Course description:

REFERENCE AND READING MATERIALS:

Refer to Appendix-A

EXERCISE AND HANDS ON:

One case study should be given to the group of four members.

TEST:

Case study given for exercise can be evaluated as part of the test.

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Course description:

INSTRUCTION TO THE FACULTY:

Course should emphasize on OO modeling.

Focus should be primarily on understanding UML[1.2] and UML diagrams and then applying to a problem.

Several excellent references are given in Appendix-A. Following are strongly recommended reading and should be used as supplementary with this power point courseware.1.UML toolkit by Eriksson and Magnus Penker

2.Object oriented analysis and design with applications by Grady Booch

Note: UML toolkit should be refereed for UML notations,their syntax and semantics.

Object oriented analysis and design with applications should be refereed for OO concepts.