Introduction To Object Oriented Analysis And Design (OOAD)
Introduction to OOAD :
Object Oriented Analysis and Desingn (OOAD) is a new way of thinking about real world system using models oranized around real world concepts. The fundamental construct in OOAD is the object. which combine both attributes ( data structure ) and operations (behavior) in a single entity.
Object Oriented Analysis and Desingn (OOAD) is a new way of thinking about real world system using models oranized around real world concepts. The fundamental construct in OOAD is the object. which combine both attributes ( data structure ) and operations (behavior) in a single entity.
What is Object -oriented ?
Specifically the term '' object-oriented'' means that we organized software as a collection od discrete object that combine both attributes and operations.
This is different than the conventional (procedural) programming in which attributes and operations are only loosely connected.
Specifically the term '' object-oriented'' means that we organized software as a collection od discrete object that combine both attributes and operations.
This is different than the conventional (procedural) programming in which attributes and operations are only loosely connected.
characterastics of objects:
Every objects has the following four properties_
1. Identity
2. Classification
3. polymorphism
4. inheritance
Every objects has the following four properties_
1. Identity
2. Classification
3. polymorphism
4. inheritance
Identity:-
Each object has its own inherent identity. In order words, two object are distinct even if all there attribute value ( such as colour and size ) are identical
For example,
Rahul's bicycle is different than that of mahesh's bicycle though their color and size may some.
In the real world an object simply exists, but within programming language each object has a uniquely identified.
Each object has its own inherent identity. In order words, two object are distinct even if all there attribute value ( such as colour and size ) are identical
For example,
Rahul's bicycle is different than that of mahesh's bicycle though their color and size may some.
In the real world an object simply exists, but within programming language each object has a uniquely identified.
classification:-
classification means that object with the same data structure (attributes) and behavior ( operations ) are grouped into class. student, account, bicycle and polygon are examples of classes.
Each class describes a possibly infinite set od individual objects. Each object is said to be an instance of its class. Each instance of the class has its own value for each attribute.
classification means that object with the same data structure (attributes) and behavior ( operations ) are grouped into class. student, account, bicycle and polygon are examples of classes.
Each class describes a possibly infinite set od individual objects. Each object is said to be an instance of its class. Each instance of the class has its own value for each attribute.
Encspdulation (Information hiding):-
it is a machanism of binding data structures (attributes) and operation of one particular object together into a single unit, thiere by hiding the details of one object from another object.
Encapsulation is not unique to object oriented language, but the ability to combine data structure and behavior in a single entity makes encapsulation cleaner and more powerful than in conventional languages that separate data structure and bhavior.
it is a machanism of binding data structures (attributes) and operation of one particular object together into a single unit, thiere by hiding the details of one object from another object.
Encapsulation is not unique to object oriented language, but the ability to combine data structure and behavior in a single entity makes encapsulation cleaner and more powerful than in conventional languages that separate data structure and bhavior.
Abstaction:-
Abstraction is one of the important features of object-oriented devele=ipment ( OOAD ), which is used fot exracting only essential deature and for ignoring non-essential features.
The goal of abstaction is to isolate those aspects that are important for some purpose and hide those aspects that are unimportant
For example, while giving the admission to the student the college only need to no the name , percentage, address, fathers name etc. about the student, they don't need to no weight, height, uncle's name etc.
While registering any vehicle at RTO office they need to no only vehicle model number, chassis number, color of vehicle, deating capacity etc. and they don't need to consider what os the color of cushion whether it has a CD player or not etc.
Abstraction is one of the important features of object-oriented devele=ipment ( OOAD ), which is used fot exracting only essential deature and for ignoring non-essential features.
The goal of abstaction is to isolate those aspects that are important for some purpose and hide those aspects that are unimportant
For example, while giving the admission to the student the college only need to no the name , percentage, address, fathers name etc. about the student, they don't need to no weight, height, uncle's name etc.
While registering any vehicle at RTO office they need to no only vehicle model number, chassis number, color of vehicle, deating capacity etc. and they don't need to consider what os the color of cushion whether it has a CD player or not etc.
Combininig Data and Behavior:-
object-oriented appoach combines data structure and behavior into a single unit called class. hirarchy unlike the conventional procedural approach as shown in following figure.
object-oriented appoach combines data structure and behavior into a single unit called class. hirarchy unlike the conventional procedural approach as shown in following figure.
Polymorphism:-
Polymorphism, a greek term, meand the ability to take more than one form poly means many and morphidm means forms.
As operation may do different things (behaviord) in different instances. The operation will generate a sum of two numbers but if the operands are strings, than the operation addition would produce a third string by concatenation or joining.
The move operation, for example, may behave differently on the bicycle, window and polygon classes
An operation is an action that an object performs or on the object to be performed. Display, move and deposikt are examples of operations.
Polymorphism, a greek term, meand the ability to take more than one form poly means many and morphidm means forms.
As operation may do different things (behaviord) in different instances. The operation will generate a sum of two numbers but if the operands are strings, than the operation addition would produce a third string by concatenation or joining.
The move operation, for example, may behave differently on the bicycle, window and polygon classes
An operation is an action that an object performs or on the object to be performed. Display, move and deposikt are examples of operations.
Inheritance:-
Inheritance is a mechanism by which one object can share the attributes and operations of another object among classes based on a hirarchical relationship. Firstly, aclass can be defined and then the subclasses of that class are created. Each subclass inherits all of the properties of its subclasses and adds itswn unique properties. the properties of the superclass need not be repeated in each subclass.
Eor enample, the attriobutes and operations of account object cn be shared by saving account and fixed- deposit account within account class.
Inheritance is a mechanism by which one object can share the attributes and operations of another object among classes based on a hirarchical relationship. Firstly, aclass can be defined and then the subclasses of that class are created. Each subclass inherits all of the properties of its subclasses and adds itswn unique properties. the properties of the superclass need not be repeated in each subclass.
Eor enample, the attriobutes and operations of account object cn be shared by saving account and fixed- deposit account within account class.
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