object_oriented_concepts_(1).pptx

7/30/2019 Object_Oriented_Concepts_(1).pptx

http://slidepdf.com/reader/full/objectorientedconcepts1pptx 1/20

Binu B Nair



Review of Object oriented Concepts

Generalization

Inheritance

Dependency Association

Abstraction

Aggregation

Composition



object Data + Methods

object State + Behavior



It would have data:

How hungry it is

How frightened it is

Where it is

And methods:

eat, hide, run



A dependency is a semantic relationship

where a change to the influent or

independent modeling element may affect

the semantics of the dependent modelingelement.

The most general relationship between two

packages



Generalization is the process of extracting shared characteristics from

two or more classes, and combining them into a generalized superclass.

Shared characteristics can be attributes, associations, or methods.

Is-a relationship

Broader level inheritance

Eg: A student is a person.



If B is a subclass of A

A objects can be assigned to A variables

B objects can be assigned to B variables

B objects can be assigned to A variables, but A objects can not be assigned to B variables

Every B is also an A but not every A is a B



class Dog { ... }

class Pomeranian extends Dog { ... }

Dog myDog;

Dog rover = new Dog ();

Pomeranian yourPomeranian;Pomeranian myPomeranian = new Pomeranian ();

myDog = rover;

yourPomeranian = myPomeranian ;

myDog = myPomeranian ;

yourPomeranian = rover; yourPomeranian = (Pomeranian ) rover;



They can exist without each other

Is a relationship where all object have their

own lifecycle and there is no owner



An abstraction relationship is a dependency

between model elements that represents the

same concept at different levels of

abstraction or from different viewpointsOne model element, the client, is more

refined or detailed than the other, the

supplier.

Abstraction relationships do not usually havenames and appear as a dashed line with an

open arrow pointing from the detailed model

element to the general model element.



Derivation

Realization



Realization is a relationship between the

blueprint class and the object containing its

respective implementation level details

The relationship between the interface andthe implementing class



“Has-a” relationship

is a specialize form of Association

All object have their own lifecycle

Child object can not belongs to anotherparent object.

Department and teacher.

A single teacher can not belongs to

multiple departments, but if we delete the

department teacher object will not destroy.

We can think about “has-a” relationship



It is a strong type of Aggregation

The Death relationship

The lifetimes of both the objects are the

same.Manager and the project objects are

dependent on each other.

If one goes for garbage collection the other

also has to be garbage collected



??



Thanks ….!!!

object_oriented_concepts_(1).pptx

Documents