BookStore Application

A Java desktop application for managing a bookstore, built with object-oriented design principles and the State design pattern. Supports two user roles, customers and an owner, each with their own set of permissions and workflows.

Tech Stack

Language: Java
UI Framework: JavaFX
Design Patterns: State Pattern, Singleton Pattern
Persistence: File I/O (BufferedReader/BufferedWriter)

Features

Customer

• Login with credentials
• Browse and select books for purchase
• Buy books using money or reward points
• Automatically earn points on purchases
• Status upgrades: Silver → Gold based on points accumulated

Owner

• Login with admin credentials
• Add and remove books from the system
• Add and remove customer accounts
• View all customers and inventory

Design Patterns Used

State Pattern

Customer loyalty status is managed using the State design pattern via a CustomerState interface implemented by SilverState and GoldState. Each state defines its own purchasing and point-earning behaviour, making it easy to add new tiers (e.g. Bronze, Diamond) without modifying existing classes.

CustomerState (interface)
├── SilverState  →  upgrades to GoldState at 1000 points
└── GoldState    →  downgrades to SilverState below 1000 points

Singleton Pattern

BookstoreSystem uses a thread-safe singleton to ensure a single shared instance manages all books, customers, and authentication across the application.

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Project Structure

phasefinal/
├── Main.java               # Entry point
├── BookstoreSystem.java    # Singleton system manager (auth, inventory, customers)
├── User.java               # Abstract base class for all users
├── Owner.java              # Owner role with admin permissions
├── Customer.java           # Customer role with points and state
├── CustomerState.java      # State interface
├── SilverState.java        # Silver tier behaviour
├── GoldState.java          # Gold tier behaviour
├── Book.java               # Book model
└── FileHandler.java        # File I/O for persisting books and customers

How to Run

1. Clone the repository
2. Open in an IDE with JavaFX configured (e.g. IntelliJ IDEA or Eclipse)
3. Run Main.java
4. Login as Owner (admin / admin) or as any existing customer

Books and customers are loaded from book.txt and customer.txt on startup and saved on exit.

UML Class Diagram

The system consists of 12 classes and 1 interface. Customer and Owner both extend the abstract User class. The BookstoreSystem singleton coordinates all interactions between the GUI, business logic, and file persistence layers.

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Built as a final project for COE528 – Object Oriented Engineering Analysis and Design at Toronto Metropolitan University (2025)