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Object Oriented Paradigm

The objected oriented paradigm is not just a programming style but also a design method for building systems.

Object oriented languages allow the programmer to specify self contained units and specify them as objects which are made up of data and the methods or operations which can be performed on the object.

In object oriented programming an object contains data and provides operations (or methods) for accessing the data. The data in an object is not visible directly and can only be accessed through the operations. In other words the operations are the interface to the object for the users of the object. This restriction of access to the data is called encapsulation.

The principle of encapsulation is essential to the object oriented paradigm. It establishes a firewall between the user of the object and the code implementing it, thus achieving information hiding. In particular, the user does not know how the data of the object is represented. Since the representation of the object is not known outside the object, it can be changed without affecting the user. Note that the interface (operations and methods) can not be changed, only data representation.

In object oriented languages – such as C++, Delphi and Java - the code within each object has variables and control structures but it is broken up into objects with their methods.

In the one object oriented program it is common to have many objects with the same structure, meaning the same data and methods. When we have objects of the same structure we refer to them as a class. An object of a particular class is said to be an instance of that class.

There are numerous concepts which are specific to the object oriented paradigm.