Object-Oriented Analysis and Design (OOAD) is a methodology used in software engineering for analyzing, designing, and developing software systems. It revolves around modeling a system as a group of interacting objects that work together to accomplish tasks and solve problems.
- Objects: These are the fundamental building blocks in OOAD. Objects encapsulate both data (attributes or properties) and behaviors (methods or functions) related to a specific entity or concept within the system. For example, in a banking system, objects might include “Account,” “Customer,” or “Transaction.”
- Classes: They define the common properties and behaviors that objects of the same type will exhibit. For instance, a “Car” class might have properties like “make,” “model,” and methods like “startEngine()”.
- Abstraction: Abstraction involves focusing on the essential qualities of an object and ignoring non-essential details. It helps in managing complexity by hiding unnecessary details while emphasizing relevant information.
- Inheritance: Inheritance allows new classes (subclasses or child classes) to inherit properties and behaviors from existing classes (superclasses or parent classes). It promotes reusability and allows for the creation of a hierarchy of classes.
- Polymorphism: It allows objects of different classes to be treated as objects of a common superclass.
- Encapsulation: Encapsulation refers to the bundling of data (attributes) and the methods (behaviors) that operate on that data into a single unit (object). It helps in data hiding and ensures that the internal workings of an object are hidden from the outside world.
The OOAD process typically involves several steps, including:
- Requirement Gathering: Understanding and documenting the system requirements.
- Analysis: Identifying objects, their attributes, relationships, and behaviors based on requirements.
- Design: Creating class diagrams, sequence diagrams, and other models to represent the system’s structure and behavior.
- Implementation: Writing code based on the design specifications.
- Testing: Verifying that the implemented system meets the requirements.
OOAD promotes modular, scalable, and maintainable software systems by emphasizing reusability, flexibility, and the ability to model real-world entities more accurately. It’s widely used in various software development methodologies like Agile, where iterative development and flexibility in accommodating changing requirements are crucial.