Level 2 CBT Course on OOAD

04/28/23TPG Confidential1

Technology Practices Group Mainframe Competency Framework

"Incubate, Nurture and Deploy Technology Experts Innovate, Build and Deliver Technology Solutions”


Business Unit BFSIGroup Technology Practices GroupPractice Mainframe PracticeSub-Practices OOAD Initiative Competency FrameworkVersion 1.0 Author Wipro Technolgies.Total number of slides

133

Duration of learning 12 Hours including case studies

IntroductionIntroduction


AgendaAgenda Why Object Oriented? Object Oriented Analysis (OOA). Approaches for Object Oriented

Analysis.a) Functional Decomposition.b) Structured Analysis.c) Data Modelling.

Object Oriented Design (OOD). OO Analysis (OOA) Vs OO Design (OOD). Object Oriented Life Cycle.


Agenda (cont.)Agenda (cont.) Basics of OOAD.

a) Object.Characteristics of an Object.

Interface.Identity.State.Behavior.

Object Construction.Object Destruction.


Agenda (cont.)Agenda (cont.)Basics of OOAD (cont.).

b) Class.Concrete Class.Abstract Class.


Agenda (cont.)Agenda (cont.) Basics of OOAD (cont.)

c) Relationship (cont.) Static Relationship (cont.)

Association. Association Types.

Unary Association.Binary Association.Parametric Association.Many-to-Many Association.Multiple Association.

Association Strategy.



c) Relationship (cont.)Static Relationship (cont.)Aggregation.Aggregation Quantification.Aggregation Quantified between classes.Aggregation as Attributes.Aggregation Strategy.


Agenda (cont.)Agenda (cont.)Basics of OOAD (cont.)

c) Relationship (cont.)Static Relationship

(cont.)Composition.


Agenda (cont.)Agenda (cont.)Basics of OOAD (cont.)

c) Relationship (cont.)Static Relationship

(cont.)Friendship.



c) Relationship (cont.)Static Relationship (cont.)Inheritance.Why Inheritance?.Inheritance Notation.Inheritance Should Reflect Specialisation.Inheritance Hierarchy.Inheritance Lattice.



c) Relationship (cont.)Dynamic Relationship.

Collaboration.Collaboration

Notation.Collaboration

Examples.


Agenda (cont.)Agenda (cont.)Basics of OOAD (cont.).

d) Instance.


Agenda (cont.)Agenda (cont.)Principles of OO.

Abstraction.Hierarchy.Encapsulation.Classification.Polymorphism.

Why Polymorphism?.


Agenda (cont.)Agenda (cont.)OO Methods.

Object-Oriented Design (OOD).Object-Oriented System Analysis (OOSA).Object-Oriented Analysis (OOA).Jacobson Use Case.Unified Modelling Language (UML).


Agenda (cont.)Agenda (cont.)Object Oriented Analysis & Design.

Identifying Objects.Organising Objects.Describing how Objects interact.Defining the operations of Objects.Identifying Classes.Design & Implementation of Classes.


Agenda (cont.)Agenda (cont.)OO Advantages & Disadvantages.Programming Object Oriented

Concepts.OO Vendors, Methodologies &

Tools.


Agenda (cont.)Agenda (cont.) Case Studies.

Small Library Database System.Case Statement/Requirement.Generic OOA Model.Class Design Diagram.Widget Retail Sail System.Case Statement/Requirement.Class Design Diagram.Two Dimensional Graphics Library.Case Statement/Requirement.Class Design Diagram.


Object Oriented Analysis and Object Oriented Analysis and DesignDesign

(OOAD)


Why Object Oriented?Why Object Oriented?Because of Growing Complexity.Divide and Conquer.Iterate and Increment.Reuse and Recycle.Strong cohesion and low

coupling.


Object Oriented Analysis Object Oriented Analysis (OOA)(OOA) The examination of a problem by

modeling it as a group of interacting objects. An object is defined by its class, data elements and behavior.

OOA looks at the problem domain, with the aim of producing a conceptual model of the information that exists in the area being analyzed. Analysis models do not consider any implementation constraints that might exist, such as concurrency, distribution, persistence, or how the system is to be built. Implementation constraints are dealt with during object-oriented design (OOD).

http://en.wikipedia.org/wiki/Problem_domain

http://en.wikipedia.org/wiki/Concurrency_%28computer_science%29

http://en.wikipedia.org/wiki/Distributed_computing

http://en.wikipedia.org/wiki/Persistence_%28computer_science%29


Object Oriented Analysis Object Oriented Analysis (OOA)..(OOA).. OOA maps the problem domain

directly into a model, instead of mapping them indirectly into functions or data flows.

The same model is used throughout the software during analysis, design and implementation.

Real-world concepts are modeled as classes with corresponding state, behavior, and collaborations.


Object Oriented Analysis Object Oriented Analysis (OOA)..(OOA)..The sources for the analysis can be a

written requirements statement, a formal vision document, interviews with stakeholders or other interested parties. A system may be divided into multiple domains, representing different business, technological, or other areas of interest, each of which are analysed separately.


Approaches for Object Approaches for Object Oriented AnalysisOriented AnalysisThere are several approaches for

object oriented analysis. Few important approaches are

a) Functional Decomposition.b) Structured Analysis.c) Data Modelling.


Functional Decomposition Functional Decomposition ModelModelMap the problem domain to a set of

function and sub-functions.Transform concepts into various functions.This model is useful to OOA within the

context of defining service.


Functional Decomposition Functional Decomposition Model (cont.)Model (cont.)


Structured Analysis ModelStructured Analysis ModelMap the problem domain to flows

and transformations.Transform concepts into various

flows and transformations.This model is not useful in system

that do not transform data.This model separates data and

functions.


Structured Analysis Model Structured Analysis Model (cont.)(cont.)


Data ModelingData Modeling The mapping of the problems domain

into the followingEntities and Attributes.Relationships.Inheritance.Aggregation.

This is partial solution which is missing specific conceptsServices.Messages.Collaboration.


Data Modeling (cont.)Data Modeling (cont.)


Object Oriented Design Object Oriented Design (OOD)(OOD)Transforming an object-oriented

model into the specifications required to create the system. Moving from object-oriented analysis to object-oriented design is accomplished by expanding the model into more and more detail.


Object Oriented Design Object Oriented Design (OOD)..(OOD)..OOD transforms the conceptual

model produced in object-oriented analysis to take account of the constraints imposed by the chosen architecture and any non-functional—technological or environmental—constraints, such as transaction throughput, response time, run-time platform, development environment, or programming language.


Object Oriented Design Object Oriented Design (OOD)..(OOD)..The concepts in the analysis

model are mapped onto implementation classes and interfaces. The result is a model of the solution domain, a detailed description of how the system is to be built.


OO Analysis Vs OO DesignOO Analysis Vs OO Design Object Oriented

AnalysisIdentify- ClassesWho am I?What is same / different?What do I contain?Who am I associated with?- AttributesWhat do I need to know?- BehaviorsWhat can I do?- CollaborationsWhat help do I need?Who needs my help?

Object Oriented Design- Decide how to implement

a) Classesb) Statec) Behaviord) Collaborations

Add Implementation-Specific Components- Human interaction.- Data Management.- Other implementation areas


Object Oriented Life CycleObject Oriented Life Cycle Conceptualization

• Establish core requirements. Analysis

• Develop a model of the desired external behavior.

Design• Create an architecture for

implementation. Evolution

• Grow and change the implementation through successive refinement.

Maintenance• Manage post-delivery evolution.


Basics Of OOADBasics Of OOADObjectClassRelationshipsInstance


ObjectObjectSome concept of reality.A physical entity.It is characterised by:

• Number of operations.• State which remembers the effect of these operations.

All Objects will have identity and are distinguishable.


Object (cont.)Object (cont.) Operations:

• Work• Dance• Drive• Jump

Attributes:• Height• Eye color• Hair color• Weight


Object (cont.)Object (cont.)

Sven Lund

Olle Macho

Ulla Rask

Anna Lind

Erik Gadd

Students

An object is an instance of a thing.

Datamodelling

Relationaldatabases

Projectmanagement

Courses

An object is something, we want to hold information about.

Feelings

A thing can be either concrete or abstract.


Characteristics of an Characteristics of an ObjectObjectThe main characteristics of an

object are- Interface.- Identity.- State.- Behavior.


Characteristics of an Object Characteristics of an Object (cont.)(cont.)


Object - InterfaceObject - InterfaceInterface consists of method

signatures.


Object - IdentityObject - IdentityIdentity of an object is the

characteristic that differentiate object from all other objects.

Two objects can be different even if their attributes, values and methods coincide.


Object - StateObject - StateThe state of an object consists of

its static attributes and their dynamic values.

Values can be primitive: int, double, boolean.

Values can be references to other objects, or they can be different objects.


Object – State (cont.)Object – State (cont.) Example

- Drinks machinea) Goes to ‘Ready’ state as soon

as you pay.b) Goes to ‘Busy’ state as soon as

you select the desired drink.c) Goes back to ‘Ready’ state

after releasing the drink can for you. Attributes – Values

Paid : BooleanCans : Number of cans


Object - BehaviorObject - BehaviorThe behavior of an object is

specified by its methods (operations).

In principle methods are conceptually equivalent to procedures/functions.

Methods = Name + Parameters + Return Values.


Object-Behavior (cont.)Object-Behavior (cont.)Example

- RectangleName of the operation: setColor()Parameter: name of the color (e.g. Red)Return Values: none.

Calling an operation of an object is referred as sending a message to the object.


Object ConstructionObject ConstructionObject construction is nothing but

- Creating an object at run time.- Intialise variables.- Allocate resources.

Object construction is achieved by ‘Constructor’ member function.


Object DestructionObject DestructionObject destruction is nothing but

- Destroy object at run time.- Deallocate (Garbage

collection) resources.Object destruction is achieved by

‘Destructor’ member function.


ClassClassA Class represents a template for

several objects and describes how these objects are structured internally.


Class (cont.)Class (cont.) Objects of the same class will have the

same definition both for their operations and their information structure.

Class is an implementation of Objects. Class is a template from which objects

can be generated. Class consists of

- A unique name.- Attributes and their types.- Methods/Operations.


Class (cont.)Class (cont.)Class name

Data members

Instance methods

ArgumentsReturn types

Data members, arguments and methods are specified byvisibility name : type

Class method


Class (cont.)Class (cont.)Classes may be further defined as

any of the following.- Abstract.- Concrete.


Abstract ClassAbstract ClassA class with no instances, but

whose descendants may have instances.

Abstract classes cannot be instantiated.


Concrete ClassConcrete ClassA class whose all

functions/methods are implemented.

A class that can be instantiated.


RelationshipsRelationshipsStatic.Dynamic.


Static RelationshipsStatic RelationshipsRelationships existing over a long

time.Objects Known about each other

existence.


Static Relationships (cont.)Static Relationships (cont.)Association.Aggregation.Parametric. Composition.Friendship.Inheritance.


AssociationAssociation Responsibilities

- An association is used to identify that one object needs another in order to fulfill its responsibilities.

Association- Association reflect associations between objects

Dependencies- You can also view associations as instantiation dependencies. - For Ex: If an object of class A is instantiated, then an Object of Class B must be instantiated.

Weak “HAS-A”

- It is sometimes called a weak “HAS-A” and can be used in place of aggregation when such a structure does make sense conceptually.


Association TypesAssociation TypesUnary Association.Binary Association.Parametric Association.Many-to-Many Association.Multiple Association.


Unary AssociationUnary AssociationOnly One Class will know about

other Class.A knows about B, but B knows nothing about A

Arrow shows direction of association in direction ofdependency


Binary AssociationBinary AssociationBoth Classes know each other.

A Knows about B and B Knows about A


Parametric AssociationParametric AssociationAssociation mediated by

Parameter.

A depends upon B, because it uses BNo data member of type B in A


Many-to-Many AssociationMany-to-Many AssociationMany-to-Many association is a

complex Binary Association.This may reflect the need for an

event remembered class as an intermediary.


Multiple AssociationMultiple AssociationThis may reflect the need for an

event remembered class.


Association StrategyAssociation StrategyFor each object or class

- Identify the associations and dependencies within the problem domain and the system’s responsibilities.

- If necessary associations can be labeled.

- Quantify associations, similar to aggregation.


Association Strategy (cont.)Association Strategy (cont.)A one-to-many association

between the Customer and Invoice classes.


Association Strategy (cont.)Association Strategy (cont.)A customer object is associated

with many Invoice object.


AggregationAggregationAggregation is a Association with

“Whole – Part” Relationship.


Aggregation (cont.)Aggregation (cont.)Aggregation is used to treat a

collection of objects as a single object.

Ex: Car Consists of Tiers and an Engine.


Aggregation (cont.)Aggregation (cont.)Aggregation is “HAS A”

relationshipFor Ex: Car HAS A Tier, Light

and Mirror.


Aggregation QuantificationAggregation QuantificationAggregation relationship can be

quantified in one of two ways depending on how relationship is viewed and the methodology you choose.- As a relationship between objects.- As a relationship between classes.


Aggregation Quantified Aggregation Quantified Between ClassesBetween ClassesThis approach is used by Booch,

Rumbaugh and in E-R Models.A ratio is used to quantify the

relationship between classes.


Aggregation Quantified Between Aggregation Quantified Between Classes (cont.)Classes (cont.)There is a one-to-many

relationship between the Airplane and Engine classes (with many bounded by 4).


Aggregation Quantified Aggregation Quantified Between Classes (cont.)Between Classes (cont.)There is one-to-many relationship

between the Airplane and CargoItem classes.


Aggregation Quantified Aggregation Quantified Between ObjectsBetween ObjectsThis is used by Coad and

Yourdon.A ratio is used to quantify the

objects.


Aggregation Quantified Aggregation Quantified Between Objects (cont.)Between Objects (cont.)An Aircraft object is connected to

0 to 4 Engine objects and many CargoItem objects.


Aggregation Quantified Aggregation Quantified Between Objects (cont.)Between Objects (cont.)Both Engine and CargoItem

objects are connected to 1 Aircraft object.


Aggregation as AttributesAggregation as AttributesBoth Aggregation and

Associations can be modeled using attributes.


Aggregation StrategyAggregation Strategy When looking for potential aggregation structures,

Consider the following.a) Assembly – Parts

- An Aircraft is an assembly with Engine(s) as parts.

b) Container – Contents- An Aircraft is a container with

CargoItem(s) as its contents.c) Collection – Members

- An Company is a collection with Employee(s) as its members.

d) Associations or Object Connections- An alternative to the aggregation

structure is the association, which is sometimes called a weak “HAS-A”


CompositionCompositionComposition is a Aggregation with Life

Time Control.

Shown by filled diamondat the "owner" sideLifetime control impliedLifetime control can betransferred

Lifetime control: construction anddestruction controlled by "owner"→ call constructors and destructors

(or have somebody else do it)


Composition (cont.)Composition (cont.)Structure Object from Parts.For Ex: Car is structured from

parts like Tiers, Lights and Mirrors.


FriendshipFriendshipFriends are granted access to

private data members and private member functions.

Friendship is given to other classes, never taken.

Friendship breaks data hiding, use carefully


InheritanceInheritanceInheritance is a parent child

relationship.Inheritance hierarchy

- Generalised class at the top and specialised classes below.

- The Specialised class name should reflect the class they were specialised from.


Inheritance (cont.)Inheritance (cont.) Inheritance is a mechanism for expressing

similarity among classes. It Portrays generalization (What is same?) and specialization (What is different?), making common attributes and services explicit within a class hierarchy.


Inheritance (cont.)Inheritance (cont.)


Why Inheritance?Why Inheritance?Show similarities.Reuse Common description.Easy modification of model by

performing modification in one place.

Avoid redundancy, leading to smaller and more efficient models, easier to understand.


Inheritance NotationInheritance Notation


Inheritance Should Reflect Inheritance Should Reflect SpecialisationSpecialisationThe Inheritance Should make

sense. Don’t introduce inheritance just for the sake of extracting out a common attribute.


Inheritance HierarchyInheritance HierarchyMost inheritance structures take

the form of tree or hierarchy.


Inheritance LatticeInheritance LatticeSome Inheritance structures take

the form of lattice, instead of hierarchy.


Inheritance Lattice (cont.)Inheritance Lattice (cont.)


Dynamic RelationshipsDynamic RelationshipsRelations which two objects communicate

with each other.Object sending stimuli to other.Stimuli – events, messages.


Dynamic Relationships Dynamic Relationships (cont.)(cont.)Collaboration.


CollaborationCollaboration Collaboration between classes is

achieved thro’ message passing Message connections model the

processing dependency of an object, indicating a need for services in order to fulfill its responsibilities.

Message connection maps one object to another, in which a sender sends a message to a receiver. The receiver performs some processing and returns the results to the sender.


Collaboration (cont.)Collaboration (cont.)Message connection exist solely

for the benefit of the services.To identify needed message

connections, ask the following for each object

- What other objects does it need services from?

- What other objects need one of its service?


Collaboration NotationCollaboration NotationThe notation for Collaboration is

a light or dashed arrow.The message connection may be

labeled to document it or numbered to show order of execution, if necessary.


Collaboration Example1Collaboration Example1 In the following example, pHContainer, pH and

pHDisplay classes will communicate with each other to perform the Display task.


Collaboration Example2Collaboration Example2 In the following example, a print queue

sends a message to a printer telling it to print a particular print job. The message connections are part of a critical thread of execution, showing their relative order of execution.


InstanceInstanceInstance is an object created from

classA class describes the behavior and

information structure of an instance, while the current state of an instance is defined by the operations performed on the instance.

System’s behavior is performed via the interactions between the instances.


Principles of OOPrinciples of OOAbstraction.Hierarchy.Encapsulation.Classification.Polymorphism.


AbstractionAbstractionThe common interface of a group

of objects is an abstraction (abstract class, interface class).

- find commonality between related objects.

- express commonality formally using interface.


HierarchyHierarchyHierarchy is nothing but inheritance.


EncapsulationEncapsulationA concept of ‘Self Containing’.Information Hiding – ‘internal’

structure is hidden from their surroundings.

Behavior or information is represented or implemented internally.

Functionality and behavior characterised by ‘interfacing’ operations.


Encapsulation (cont.)Encapsulation (cont.)Encapsulation is the mechanism

that binds together code and the data it manipulates and keeps both safe from outside interference and misuse.


Encapsulation (cont.)Encapsulation (cont.) In the following example only the

services move() and scale() modify the attributes of Circle. The service draw() performs some computation based on the values of the attribute.


ClassificationClassificationClassification is used to group entities that

share common characteristics into a class over which uniform conditions hold.


PolymorphismPolymorphismA concept in type theory.A common name may donate

instances of different classes.One type of operation can be

implemented in different ways by different classes.

Overloading in modern OO language.


Why Polymorphism?Why Polymorphism?A very strong tool for allowing

system designers to develop flexible systems.

Designer only need to specify what shall occur not how it shall occur.

To add an object, the modification will only affect the new object, not those using it.


OO MethodsOO Methods Object-Oriented Design (OOD) – Booch

(1983), pioneering but not scalable. Object-Oriented System Analysis

(OOSA) – Shlaer & Mellor (1988), essentially information analysis based on data modeling.

Object-Oriented Analysis (OOA) – Coad & Yourdon (1991), a method for developing OO system model.


OO Methods (cont.)OO Methods (cont.)Jacobson Use Case – Jacobson et

al.(1992), requirement modeling, analysis and design also known as OOSE.

Unified Modeling Language (UML) – Booch, Rumbaugh, Jacobson (1997-2000), a method that provides a united OO approach to system development.


Object Oriented Analysis & Object Oriented Analysis & DesignDesignIdentifying Objects.Organising Objects.Describing how Objects interact.Defining the operations of

Objects.Identifying Classes.Design & Implementation of

Classes.


Identifying ObjectsIdentifying ObjectsNaturally occurring entities –

physical.A concept of some abstract ideas –

conceptual.Should be stable.Textual analysis of nouns

Ex: Each customer has an account that he may pay into, debit from or enquire as to the current balance.


Identifying Objects (cont.)Identifying Objects (cont.) Textual examination of verbs

Ex: Mail items may be edited, sent or received.

Types of Objects- active/passive.- temporary/permanent/persistent.- part/whole.- generic/specific.- private/public.


Organising ObjectsOrganising ObjectsClassification.Similar objects – inheritance: ‘is

a’.Interactions/relationships

between objects.Whole/Part relationship: ‘has a’.


Object InteractionsObject InteractionsIdentify how objects fit into a

system.Use of scenarios – unique

situations.Objects communication.Objects Interfaces.Refined relationships.


Defining operations of Defining operations of objectsobjects Consider objects responsibility. Behavior of an object. Examine verbs.

Ex:Each customer has an account that he may credit into, debit from or enquire as to the current balance.

Thought experiments and scenarios. Objects with complex functionality

should be partitioned into simpler objects.


Identifying ClassesIdentifying ClassesNominate a class for each different kind of

object.Ex:


Design & Implementation of Design & Implementation of ClassesClasses The Specification of CLASSES. Define information that an object encapsulates

– ATTRIBUTES and METHODS. METHODS.

Specify external functions. Specify internal functions that are not seen or

usable by other objects. ATTRIBUTES.

Specify static / dynamic attributes. LANGUAGE.

Select the Language in which you want to implement the class. For Ex: C, C++, Java etc.


OO Advantages & OO Advantages & DisadvantagesDisadvantages Advantages.

- Enhanced modularity.- Unified approach.- Reuse and extendibility through..Inheritance.Polymorphism.Encapsulation.- Incremental life cycle useful when requirements are not well understood.

Disadvantages.- Immaturity of technique and tools.- Lack of standard notation.- Commitments required for maximising reuse.- Inheritance complicates testing.- Incremental life cycle poses management challenges.


Programming Object Oriented Programming Object Oriented ConceptsConcepts


OO Vendors, Methodologies OO Vendors, Methodologies and Toolsand Tools Object International Inc. (http://www.oi.com)

Methodology.Coad and Yourdon.

Tools.Together C++.Playground.

Rational Software Corporation (http://www.rational.com) – Now part of IBM.

Methodology.Booch.Rumbaugh.UML.

Tools.Rational Rose.Rational CRC.

http://www.oi.com/

http://www.rational.com/


Case Studies.Case Studies.Convert the OOA model into OOD model

by adding appropriate design component.


Small Library Database Small Library Database SystemSystemCase Statement/Requirement.

A Small Library Database System will be used by the Biology department of local college to track the borrowing of books and other forms of media, such as video tapes and software. A secretary will operate the system and will be responsible for checking out books to students and faculty members.


Small Library Database System Small Library Database System (cont.)(cont.) Generic OOA Model

Use the basic class/state/behavior/collaboration OOA notation to describe the OOA notation itself. This might be necessary, for ex if you were to develop a case tool that supported this approach.Hints:- Start out by listing every concept in the notation, such as attributes and whole-part structures.- Build structures from these concepts. For ex: a class HAS attributes.- Add support for secondary models and documentation, such as subject and data flow diagrams.


Small Library Database System Small Library Database System (cont.)(cont.)Generic OOA Model


Small Library Database System Small Library Database System (cont.)(cont.)OOD Model


Widget Retail System.Widget Retail System. Case Statement/Requirement.

A certain company maintains an inventory of widgets, which it sells to the general public. Widgets are identified by size, color and the number currently in the inventory. The system should also maintain information on the name, address, phone number and the credit limit of customers and the name, address, phone number, social security number, salary and job title of employees


Widget Retail System Widget Retail System (cont.)(cont.) Case Statement/Requirement (cont.)

For each sale, the system should keep track of the widgets purchased. A sale may include a number of line items. For example a customer may purchase 5 big blue widgets and 3 little red widgets. System should compute a subtotal of each line item, tax, and final total. In addition we want to know the customer and employee involved in the sale. The system also keep track of purchase orders from widget suppliers. A list of suppliers is maintained that includes name, address, phone number and the suppliers wholesale price for the various widgets it carries.


Widget Retail System Widget Retail System (cont.)(cont.)OOD Model


Graphics LibraryGraphics Library Case Statement/Requirement

Develop an OOA model for two-dimensional graphics library that can be incorporated in applications which require graphics. The system should support points, rectangles, circles. The system should support color as well as drawing, rotation, moving and scaling those objects for which these services are appropriate. Hint: Use an abstract class to define generalised graphical object.Hint: A location is a position. A point is a graphical object.Hint: Don’t use line graphical object as an intermediate class.


Graphics Library (cont.)Graphics Library (cont.) Case Statement/Requirement

(cont.)Continue with OOD by adding the necessary classes to the OOA results to create an implementation specific problem domain component. Show how the graphics system could support at least two output devices: a plotter and a monitor.


Graphics Library (cont.)Graphics Library (cont.)OOD Model


Thank You

Level 2 CBT Course on OOAD

Documents

Transcript of Level 2 CBT Course on OOAD