🚗 Abstract Factory Vehicle System – Java

A Java implementation of Abstract Factory and Singleton design patterns developed for the SLIIT OOP (Object-Oriented Programming) module.
This project simulates a Vehicle Factory that produces Cars and Buses from specific factories.

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📚 Project Overview

This system demonstrates the use of:

• Abstract Factory Pattern → To create families of related objects (CarFactory and BusFactory).
• Singleton Pattern → To ensure only one instance of each factory and vehicle type exists.
• Interfaces → To achieve loose coupling between products (Cars and Buses).

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🧱 Class Structure Overview

1️⃣ VehicleProducer

• Acts as the abstract factory selector.
• Returns CarFactory or BusFactory via the getVehicle(String choice) method.

2️⃣ CarFactory & BusFactory

• Implement the Singleton Pattern.
• Provide the getModel(String vehicle) method to return the correct car or bus object.

3️⃣ Car Models

• BMW, Benz, and RollsRoyce
• Each follows Singleton design and implements ICar interface.
• Each overrides the displayVehicle() method.

4️⃣ Bus Models

• Volvo, Fuso, and TATA
• Each follows Singleton design and implements IBus interface.
• Each overrides the displayVehicle() method.

5️⃣ Interfaces

• ICar: Declares displayVehicle() for car models.
• IBus: Declares displayVehicle() for bus models.
• VehicleFactory: Declares getModel(String vehicle) for factory classes.

6️⃣ VehicleDemo (Main Class)

• Demonstrates factory selection and vehicle creation:

  VehicleFactory carFactory = VehicleProducer.getVehicle("Car");
  ICar car1 = (ICar) carFactory.getModel("BMW");
  car1.displayVehicle();

Pattern	Purpose
Abstract Factory	To encapsulate creation of related vehicle families
Singleton	To ensure a single shared instance of each factory and model
Interface Segregation	To separate car and bus behaviors clearly

⚙️ How to Run

Clone the Repository

git clone https://github.com/dyneth02/AbstractFactory-VehicleSystem-Java.git cd AbstractFactory-VehicleSystem-Java

Compile the Java Files

javac *.java

Run the Demo

java VehicleDemo

Expected Output Example

--- Vehicle Factory Demo --- Selected Factory: CarFactory BMW: Luxury performance car displayed. Benz: Premium comfort car displayed. RollsRoyce: Ultimate luxury car displayed.

Selected Factory: BusFactory Volvo: City transport bus displayed. Fuso: Commercial transport bus displayed. TATA: Long-distance travel bus displayed.

🧠 Concepts Demonstrated

Abstract Factory Pattern Singleton Pattern Factory Method Pattern Polymorphism and Interfaces Encapsulation and Object Reuse