Object-Oriented Software Development Notes

1. Introduction: Two Views of Software Development

Breaks systems into processes and data flows, focusing on functional decomposition.
Uses procedural programming, separating data and functions.
Relies on tools like data flow diagrams (DFDs) and entity-relationship diagrams (ERDs).
Challenges: Hard to maintain, less adaptable to changes, and struggles with complex systems.

Models systems as collections of interacting objects that combine data and behavior.
Promotes modularity, reusability, and scalability.
Aligns with real-world problem domains, making systems easier to understand and evolve.

Key Difference: SSAD emphasizes "what the system does" (functions), while OOAD focuses on "what the system is" (objects and interactions).

Natural Modeling: Objects reflect real-world entities, making systems intuitive.
Modularity: Encapsulation and clear interfaces reduce complexity.
Reusability: Inheritance and polymorphism enable code reuse, saving development time.
Maintainability: Encapsulated objects are easier to modify without impacting the entire system.
Scalability: OO systems handle large, complex projects effectively.
Business Alignment: OOAD aligns software design with business processes, improving stakeholder communication.

Objects: Fundamental units representing entities with state (data) and behavior (methods). Example: A "Car" object has attributes like color and speed, and behaviors like drive or stop.
Classes: Blueprints defining the structure and behavior of objects. Example: A "Car" class specifies properties and methods shared by all car objects.
Relationship: Objects are instances of classes; a class is a template, and an object is its concrete realization.
Key Benefit: Classes provide abstraction, ensuring reuse and consistency across objects.

Abstraction: Simplifies systems by focusing on essential characteristics and ignoring irrelevant details. Example: A "Bank Account" class abstracts balance and transactions, hiding internal calculations.
Encapsulation: Bundles data and methods within an object, restricting direct access to its internal state. Ensures data integrity and modularity by exposing only necessary interfaces.
Benefits: Reduces complexity, enhances maintainability, and supports information hiding.

Methods: Functions or procedures within a class that define an object’s behavior. Example: A "Dog" class may have a "bark" method.
Messages: Requests sent to objects to invoke their methods. Example: Sending a "bark" message to a Dog object triggers its bark method.
Key Benefit: Messages enable object interaction, supporting dynamic and flexible system behavior while maintaining loose coupling through well-defined interfaces.

Interfaces: Define a contract of methods a class must implement, without specifying how. Example: A "Drawable" interface for shapes ensures consistent method signatures.
Inheritance: Allows a subclass to inherit attributes and methods from a superclass. Example: A "SportsCar" class inherits from a "Car" class, adding specialized features.
Polymorphism: Enables objects of different classes to be treated uniformly via a common interface or superclass. Example: A "Shape" superclass allows "Circle" and "Rectangle" objects to respond to a "draw" method differently.
Benefits: Interfaces promote interoperability, inheritance supports code reuse, and polymorphism enhances flexibility and extensibility.

Definition: Mechanisms to restrict access to an object’s data and methods using modifiers like public, private, or protected.
Purpose: Protects data integrity by preventing unauthorized access and supports encapsulation by exposing only necessary parts of an object.
Example: A "Bank Account" class may have a private balance attribute, accessible only through public deposit or withdraw methods.
Key Benefit: Ensures robust, secure, and maintainable systems.

Cost Efficiency: Reusability through inheritance and polymorphism reduces development and maintenance costs.
Adaptability: Encapsulation and modularity make systems easier to modify for changing business needs.
Scalability: OO systems effectively manage growing complexity, ideal for large-scale enterprise applications.
Improved Communication: Object models align with business domains, easing collaboration between developers and stakeholders.
Faster Development: Reusable components and frameworks accelerate development cycles.
Competitive Advantage: OOAD supports rapid prototyping and iterative development, enabling quick responses to market demands.

2024-25

What do you understand by object-orientation? Explain objects and classes.
What is Inheritance? Explain its types with a suitable example.
What do you understand by SSAD and OOAD? Why is it important?

2023-24

What is Polymorphism? Explain its types with a suitable example.
What is Inheritance? Explain its types with a suitable example.
Write short notes on:
- Interface
- Classes
- Encapsulation
- SSAD

2022-23

Explain Object Oriented Analysis (OOA) and Object Oriented Design (OOD) in brief. Differentiate SSAD and OOAD.
Explain object oriented methodology with examples of any two methods.
Write short notes on:
- Abstraction and Encapsulation
- Polymorphism

2021

What do you understand by SSAD and OOAD? Why is it important?
What do you mean by object oriented software engineering? Explain its characteristics in detail.
Describe object oriented design modelling and analysis.

2019 & 2018-19

Describe the software development process. Write the difference between SSAD and OOAD.
Explain the following terms:
- Abstraction and Encapsulation
- Interface
- Inheritance
Explain Booch methodology of object oriented design.

Describe the software development process. Write the difference between SSAD and OOAD.
Explain Booch methodology of object oriented design.
What is an object and class? Distinguish between method and message in object.

2017 & 2015

Explain the various models available in object oriented languages. Also explain the relationship among different models.
What are the object modeling techniques given by Rumbaugh? Explain with example.
Write short notes on:
- Inheritance and Polymorphism
- Abstraction and Encapsulation

What are the various diagrams used in analysis and design steps of Booch Methodology? Explain with example.
Describe the necessary conditions that a system must satisfy to be considered an object oriented system.
Write short notes on any two:
- Object Oriented Analysis — Coad-Yourdan
- Methods and Message
- Business case of OO development

Booch, G. (1994). Object-Oriented Analysis and Design with Applications. Benjamin/Cummings.
Rumbaugh, J., Blaha, M., Premerlani, W., et al. (191). Object-Oriented Modeling and Design. Prentice Hall.
Eliens, A. (2000). Principles of Object-Oriented Software Development. Addison Wesley.
Bahrami, A. (1999). Object-Oriented System Development. McGraw-Hill.
Jacobson, I. (1992). Object-Oriented Software Engineering. Pearson Education Inc.
Wirfs-Brock, R., Wilkerson, B., & Wiener, L. (1990). Designing Object-Oriented Software. Prentice Hall.