Airline Reservation System (Java)

A comprehensive console-based simulation of an Airline Reservation System (ARS). This application manages the complex relationships between Flights, Passengers, and Reservations without relying on a SQL database.

It demonstrates advanced Object-Oriented principles, including manual Dependency Injection, custom Comparators for scheduling, and robust string parsing for data persistence.

---

✈️ Key Features

📅 Flight Scheduling Engine

• Management: create and modify flight schedules with validation for unique Flight IDs (Fxxxx format).
• Sorting Algorithm: Implements Collections.sort with a custom Comparator to organize flights dynamically by departure time.

🎫 Reservation Pipeline

• Booking Logic: A multi-step process that links specific Passengers to Flights, generating a unique Reservation ID.
• Seat Allocation: Handles "Check-In" logic to assign gates and seats to passengers.
• Capacity Checks: Automatically validates available seats (AvailSeat) before confirming a reservation.

💾 Data Persistence

• State Preservation: The system creates and reads from structured text files (ReservationID.txt, FlightDetails.txt) to maintain state between sessions.
• Complex Parsing: Utilizes BufferedReader and regex to reconstruct complex Object graphs (Reservation -> Flight -> List) from raw text.

---

🛠️ Technical Highlights

Dependency Injection

To ensure data consistency between different modules, the system uses constructor injection to share the FlightList instance with the ReservationList.

// From ReservationList.java
public ReservationList(FlightList flightList) {
    this(); 
    this.flightList = flightList; // Logic injection for data consistency
}

Relational Data Modeling

Unlike simple list-based apps, this project models real-world constraints where objects encapsulate other objects:

public class Reservation {
    private int reservationId;
    private Flight flight; // Object composition
    ArrayList<Passenger> passenger; // One-to-Many relationship
    // ...
}

🚀 How to Run

1. Clone the repository:

git clone https://github.com/TonyTheSlacker/FlightReservation.git

2. Compile the source:

javac Main.java

3. Run the application:

java Main

---

Note: The application expects data files (FlightDetails.txt, etc.) to exist. If they are missing, the system will start with an empty database and generate them upon saving.