OBJECT-ORIENTED PROGRAMMING PARADIGMS

OBJECT-ORIENTED PROGRAMMING PARADIGMS

The object-oriented approach to programming is an easy way to master the management and complexity in developing software systems that take advantage of the strengths of data abstraction. Data-driven methods of programming provide a disciplined approach to the problems of data abstraction, resulting in the development of object-based languages that support only data abstraction. These object-based languages do not support the features of the object-oriented paradigm, such as inheritance or polymorphism. Depending on the object features supported, there are two categories of object languages:

1. Object-Based Programming Languages

2. Object-Oriented Programming Languages

Object-based programming languages support encapsulation and object identity (unique property

to differentiate it from other objects) without supporting important features of OOP languages such as polymorphism, inheritance, and message based communication, although these features may be emulated to some extent. Ada, C, and Haskell are three examples of typical object-based programming languages.

Object-based language = Encapsulation + Object Identity

Object-oriented languages incorporate all the features of object-based programming languages, along with inheritance and polymorphism (discussed later in this chapter). Therefore, an object-oriented programming language is defined by the following statement:

Object-oriented language = Object-based features + Inheritance + Polymorphism

Object-oriented programming languages for projects of any size use modules to represent the physical building blocks of these languages. A module is a logical grouping of related declarations, such as objects or procedures, and replaces the traditional concept of subprograms that existed in earlier languages.

The following are important features in object-oriented programming and design:

1. Improvement over the structured programming paradigm.

2. Emphasis on data rather than algorithms.

3. Procedural abstraction is complemented by data abstraction.

4. Data and associated operations are unified, grouping objects with common attributes, operations, and semantics. Programs are designed around the data on which it is being operated, rather than the operations themselves. Decomposition, rather than being algorithmic, is data-centric. Clear understanding of classes and objects are essential for learning object-oriented development. The concepts of classes and objects help in the understanding of object model and realizing its importance in solving complex problems. Object-oriented technology is built upon object models. An Object is anything having crisply defined conceptual boundaries. Book, pen, train, employee, student, machine, etc., are examples of objects. But the entities that do not have crisply defined boundaries are not objects. Beauty, river, sky, etc., are not objects.

Model is the description of a specific view of a real-world problem domain showing those aspects, which are considered to be important to the observer (user) of the problem domain. Object-oriented programming language directly influences the way in which we view the world. It uses the programming paradigm to address the problems in everyday life. It addresses the solution closer to the problem domain.

Object model is defined by means of classes and objects. The development of programs using object model is known as object-oriented development. To learn object-oriented programming concepts, it is very important to view the problem from the user’s perspective and model the solution using object model.