vehicle-rental-system.md

Designing a Vehicle Rental System

In this article, we explore the object-oriented design and implementation of a Vehicle Rental System using Java.

This system facilitates the renting of vehicles for short and long durations.

System Requirements

The Vehicle Rental System should:

1. Vehicle Management: Handle various types of vehicles available for rent.
2. User Account Management: Manage customer registrations and profiles.
3. Rental Process: Enable users to rent and return vehicles.
4. Pricing and Payment: Calculate rental charges and process payments.
5. Reservation System: Support advance booking of vehicles.

Core Use Cases

1. Adding and Managing Vehicles
2. Registering and Managing User Accounts
3. Renting and Returning Vehicles
4. Calculating Rental Charges
5. Handling Reservations

Key Classes:

• VehicleRentalSystem: Manages the overall system.
• User: Represents a system user or customer.
• Vehicle: Abstract class for various types of vehicles.
• Rental: Represents a vehicle rental transaction.

Java Implementation

Vehicle Class (Abstract)

Represents a generic vehicle.

public abstract class Vehicle {
    private String vehicleId;
    private String model;
    private double ratePerDay;

    public Vehicle(String vehicleId, String model, double ratePerDay) {
        this.vehicleId = vehicleId;
        this.model = model;
        this.ratePerDay = ratePerDay;
    }

    // Getters and setters...
}

User Class

Manages user account information.

public class User {
    private String userId;
    private String name;
    private String driverLicenseNumber;

    public User(String userId, String name, String driverLicenseNumber) {
        this.userId = userId;
        this.name = name;
        this.driverLicenseNumber = driverLicenseNumber;
    }

    // Getters and setters...
}

Rental Class

Represents a vehicle rental transaction.

import java.util.Date;

public class Rental {
    private String rentalId;
    private User user;
    private Vehicle vehicle;
    private Date rentalDate;
    private Date returnDate;
    private double totalCharge;

    public Rental(String rentalId, User user, Vehicle vehicle, Date rentalDate) {
        this.rentalId = rentalId;
        this.user = user;
        this.vehicle = vehicle;
        this.rentalDate = rentalDate;
    }

    public void completeRental(Date returnDate) {
        this.returnDate = returnDate;
        this.totalCharge = calculateTotalCharge();
    }

    private double calculateTotalCharge() {
        // Calculate total charge based on rental duration and vehicle rate
        long rentalDays = (returnDate.getTime() - rentalDate.getTime()) / (1000 * 60 * 60 * 24);
        return rentalDays * vehicle.getRatePerDay();
    }

    // Getters and setters...
}

VehicleRentalSystem Class

Manages the vehicle rental system operations.

import java.util.ArrayList;
import java.util.List;

public class VehicleRentalSystem {
    private List<User> users;
    private List<Vehicle> vehicles;
    private List<Rental> rentals;

    public VehicleRentalSystem() {
        this.users = new ArrayList<>();
        this.vehicles = new ArrayList<>();
        this.rentals = new ArrayList<>();
    }

    public void addUser(User user) {
        users.add(user);
    }

    public void addVehicle(Vehicle vehicle) {
        vehicles.add(vehicle);
    }

    public Rental rentVehicle(String userId, String vehicleId, Date rentalDate) {
        User user = findUserById(userId);
        Vehicle vehicle = findVehicleById(vehicleId);

        if (user != null && vehicle != null) {
            Rental rental = new Rental(generateRentalId(), user, vehicle, rentalDate);
            rentals.add(rental);
            return rental;
        }
        return null;
    }

    public void returnVehicle(String rentalId, Date returnDate) {
        Rental rental = findRentalById(rentalId);
        if (rental != null) {
            rental.completeRental(returnDate);
        }
    }

    private User findUserById(String userId) {
        for (User user : users) {
            if (user.getUserId().equals(userId)) {
                return user;
            }
        }
        return null;
    }

    private Vehicle findVehicleById(String vehicleId) {
        for (Vehicle vehicle : vehicles) {
            if (vehicle.getVehicleId().equals(vehicleId)) {
                return vehicle;
            }
        }
        return null;
    }

    private Rental findRentalById(String rentalId) {
        for (Rental rental : rentals) {
            if (rental.getRentalId().equals(rentalId)) {
                return rental;
            }
        }
        return null;
    }

    private String generateRentalId() {
        return "RENTAL_" + System.currentTimeMillis();
    }
    
    // Other necessary methods...