🏦 Finance Bank — Employee Back-Office System

A production-quality Banking Employee System built with Java, featuring both CLI and JavaFX GUI interfaces.

Features • Architecture • Installation • Usage • Testing

📋 Overview

A comprehensive Banking Employee Back-Office System implemented in Java, designed using clean Object-Oriented Programming (OOP) principles and a layered architecture. The system features strong validation, custom exception handling, audit logging, automated testing, CSV export, and a full JavaFX Desktop GUI.

This project simulates how bank employees manage customers, accounts, and transactions through:

Interface	Description
🖥️ CLI Application	Console-based interface for terminal users
🪟 JavaFX Desktop GUI	Modern desktop application with rich UI
🧪 JUnit 5 Test Suite	Comprehensive automated testing
📤 CSV Export System	Transaction history export with multiple modes
🔐 RBAC Security	Role-Based Access Control

⚠️ Scope Notice: This system represents employee-assisted banking operations only. No customer self-service, online banking, or external transfers.

🛠️ Tech Stack

Category	Technology	Version
Language	Java	17 (LTS)
GUI Framework	JavaFX	21.0.2
Build Tool	Maven	3.x
Testing	JUnit Jupiter	5.10.1
Architecture	Layered / MVC	-
Data Storage	In-Memory (Repository Pattern)	-

✨ Features

🔐 Authentication & Authorization

Role	Code	Permissions
Customer Service	`CS`	Create customers, Open accounts
Teller	`TELLER`	Deposit, Withdraw, View transactions
Manager	`MANAGER`	Full system access (all operations)

Employee login with username/password validation
Role-based access control enforced at service layer
Secure session management (login/logout)
Authorization checks on every operation

👤 Customer Management

Create customers with Egyptian National ID validation
Comprehensive National ID validation:
- 14-digit format validation
- Birth date extraction and validation
- Governorate code verification (35 valid codes)
- Century detection (2xxx = 1900s, 3xxx = 2000s)
Prevent duplicate customers (unique National ID)
List customers with account count
Search customers by National ID

💳 Account Management

Account Type	Overdraft	Withdrawal Limit
Savings Account	❌ No	Limited to balance
Current Account	✅ Yes	Configurable limit

16-digit account numbers (system-generated)
Multiple accounts per customer supported
Account numbers masked in display (e.g., XXXXXXXXXXXX3456)
Account validation with custom exceptions

💰 Transaction System

Feature	Description
Deposit	Add funds to any account (no fee)
Withdrawal	Remove funds with 1% fee
Fee Calculation	Real-time fee display in GUI
Balance Validation	Polymorphic rules per account type

Transaction Record (Immutable):

├── Transaction ID (unique)
├── Type (DEPOSIT / WITHDRAWAL)
├── Amount
├── Fee (1% for withdrawals)
├── Total (Amount + Fee)
├── Balance After
├── Timestamp
├── Account Number
└── Audit Trail
    ├── Employee ID
    ├── Employee Name
    └── Employee Role

📤 CSV Export System

Three Export Modes:

Mode	Trigger	File Pattern
By Customer	Filter by National ID	`transactions_customer_{nationalId}.csv`
All Transactions	Show All view	`transactions_all_{timestamp}_by_{employee}.csv`
By Account	Legacy/API	`transactions_account_{accountNumber}.csv`

Export Features:

Incremental export (append-only, no duplicates)
Excel-compatible CSV format
Automatic exports/ directory creation
Timestamp tracking per export key

CSV Format:

AccountNumber,Type,Amount,BalanceAfter,PerformedBy,Role,Timestamp,TransactionId

🇪🇬 Egyptian National ID Validation

The system validates Egyptian National IDs according to official format:

Position:  1  | 2-3 | 4-5 | 6-7 | 8-9  | 10-13 | 14
Content:   C  | YY  | MM  | DD  | GOV  | SEQ   | CHECK

Component	Description
Century (C)	`2` = 1900s, `3` = 2000s
Year (YY)	Birth year (00-99)
Month (MM)	Birth month (01-12)
Day (DD)	Birth day (01-31)
Governorate (GOV)	35 valid codes (01-35)
Sequence (SEQ)	Unique identifier
Check (CHECK)	Validation digit

🏗️ Architecture

┌─────────────────────────────────────────────────────────────┐
│                    PRESENTATION LAYER                       │
├─────────────────────────────┬───────────────────────────────┤
│      CLI (Console)          │       JavaFX (Desktop)        │
│  ┌─────────────────────┐    │    ┌─────────────────────┐    │
│  │ BankEmployeeCLI     │    │    │ MainApp             │    │
│  │ LoginView           │    │    │ LoginController     │    │
│  │ MenuView            │    │    │ DashboardController │    │
│  │ CustomerView        │    │    │ CustomerFormCtrl    │    │
│  │ AccountView         │    │    │ AccountFormCtrl     │    │
│  │ TransactionView     │    │    │ TransactionFormCtrl │    │
│  └─────────────────────┘    │    └─────────────────────┘    │
├─────────────────────────────┴───────────────────────────────┤
│                      SERVICE LAYER                          │
│  ┌─────────────────────────────────────────────────────┐    │
│  │ BankService (Facade + Singleton)                    │    │
│  │ ├── AuthenticationService                           │    │
│  │ ├── AuthorizationService                            │    │
│  │ ├── AccountService                                  │    │
│  │ └── TransactionService                              │    │
│  └─────────────────────────────────────────────────────┘    │
├─────────────────────────────────────────────────────────────┤
│                    REPOSITORY LAYER                         │
│  ┌─────────────────────────────────────────────────────┐    │
│  │CustomerRepository │ AccountRepository │ TxRepository│    │
│  └─────────────────────────────────────────────────────┘    │
├─────────────────────────────────────────────────────────────┤
│                      DOMAIN LAYER                           │
│  ┌─────────────────────────────────────────────────────┐    │
│  │ Person ← Customer, Employee                         │    │
│  │ Account ← SavingsAccount, CurrentAccount            │    │
│  │ Transaction, TransactionType, AccountType           │    │
│  │ EmployeeRole                                        │    │
│  └─────────────────────────────────────────────────────┘    │
├─────────────────────────────────────────────────────────────┤
│                      UTILITY LAYER                          │
│  ┌─────────────────────────────────────────────────────┐    │
│  │ NationalIdValidator │ AccountValidator │ IdGenerator│    │
│  │ NumberFormatter │ TransactionPrinter                │    │
│  └─────────────────────────────────────────────────────┘    │
└─────────────────────────────────────────────────────────────┘

📂 Project Structure

banking-system/
│
├── pom.xml                          # Maven configuration
├── README.md                        # This file
│
├── exports/                         # CSV export output directory
│   ├── transactions_customer_*.csv
│   └── transactions_all_*.csv
│
├── src/
│   ├── main/
│   │   ├── java/com/finance/bank/
│   │   │   │
│   │   │   ├── app/                 # Entry Points
│   │   │   │   ├── BankEmployeeCLI.java
│   │   │   │   └── MainApp.java
│   │   │   │
│   │   │   ├── model/               # Domain Models
│   │   │   │   ├── Person.java
│   │   │   │   ├── Customer.java
│   │   │   │   ├── Employee.java
│   │   │   │   ├── EmployeeRole.java
│   │   │   │   ├── Account.java
│   │   │   │   ├── SavingsAccount.java
│   │   │   │   ├── CurrentAccount.java
│   │   │   │   ├── AccountType.java
│   │   │   │   ├── Transaction.java
│   │   │   │   └── TransactionType.java
│   │   │   │
│   │   │   ├── repository/          # Data Access Layer
│   │   │   │   ├── CustomerRepository.java
│   │   │   │   ├── AccountRepository.java
│   │   │   │   └── TransactionRepository.java
│   │   │   │
│   │   │   ├── service/             # Business Logic
│   │   │   │   ├── BankService.java
│   │   │   │   ├── AuthenticationService.java
│   │   │   │   ├── AuthorizationService.java
│   │   │   │   ├── AccountService.java
│   │   │   │   └── TransactionService.java
│   │   │   │
│   │   │   ├── exception/           # Custom Exceptions
│   │   │   │   ├── InvalidNationalIdException.java
│   │   │   │   ├── DuplicateNationalIdException.java
│   │   │   │   ├── InvalidAccountException.java
│   │   │   │   ├── DuplicateAccountException.java
│   │   │   │   ├── InvalidAmountException.java
│   │   │   │   ├── InsufficientAmountException.java
│   │   │   │   ├── AuthenticationException.java
│   │   │   │   ├── UnauthorizedException.java
│   │   │   │   ├── AccessDeniedException.java
│   │   │   │   └── ResourceNotFoundException.java
│   │   │   │
│   │   │   ├── util/                # Utilities
│   │   │   │   ├── NationalIdValidator.java
│   │   │   │   ├── AccountValidator.java
│   │   │   │   ├── IdGenerator.java
│   │   │   │   ├── NumberFormatter.java
│   │   │   │   └── TransactionPrinter.java
│   │   │   │
│   │   │   ├── view/                # CLI Views
│   │   │   │   ├── LoginView.java
│   │   │   │   ├── MenuView.java
│   │   │   │   ├── CustomerView.java
│   │   │   │   ├── AccountView.java
│   │   │   │   ├── TransactionView.java
│   │   │   │   └── InputValidator.java
│   │   │   │
│   │   │   └── presentation/        # JavaFX Layer
│   │   │       ├── controllers/
│   │   │       │   ├── LoginController.java
│   │   │       │   ├── DashboardController.java
│   │   │       │   ├── DashboardHomeController.java
│   │   │       │   ├── CustomerFormController.java
│   │   │       │   ├── CustomerListController.java
│   │   │       │   ├── AccountFormController.java
│   │   │       │   ├── AccountListController.java
│   │   │       │   ├── TransactionFormController.java
│   │   │       │   ├── TransactionHistoryController.java
│   │   │       │   └── EmployeeAware.java
│   │   │       └── util/
│   │   │           ├── NavigationManager.java
│   │   │           ├── SessionManager.java
│   │   │           └── AlertHelper.java
│   │   │
│   │   └── resources/com/finance/bank/presentation/
│   │       ├── views/               # FXML Files
│   │       │   ├── login.fxml
│   │       │   ├── dashboard.fxml
│   │       │   ├── dashboard_home.fxml
│   │       │   ├── customer_form.fxml
│   │       │   ├── customer_list.fxml
│   │       │   ├── account_form.fxml
│   │       │   ├── account_list.fxml
│   │       │   ├── transaction_form.fxml
│   │       │   └── transaction_history.fxml
│   │       └── css/
│   │           └── bank-theme.css   # Custom Theme
│   │
│   └── test/java/com/finance/bank/test/
│       └── BankingSystemTest.java   # JUnit 5 Tests
│
└── target/                          # Build output
    └── banking-system-2.0.0.jar

❗ Custom Exceptions

Exception	Scenario
`InvalidNationalIdException`	National ID format/validation failed
`DuplicateNationalIdException`	Customer already exists
`InvalidAccountException`	Account validation failed
`DuplicateAccountException`	Account number already exists
`InvalidAmountException`	Amount ≤ 0 or invalid format
`InsufficientAmountException`	Balance/overdraft limit exceeded
`AuthenticationException`	Login credentials invalid
`UnauthorizedException`	Employee lacks permission
`AccessDeniedException`	Access to resource denied
`ResourceNotFoundException`	Requested resource not found

🧠 Design Patterns

Pattern	Implementation	Purpose
Singleton	`BankService`	Single point of access to business logic
Facade	`BankService`	Simplified API for complex subsystems
Repository	`*Repository` classes	Abstract data storage operations
MVC	JavaFX Controllers + FXML	Separation of concerns in GUI
Strategy	`Account.withdraw()`	Different withdrawal rules per account type
Template Method	`Account` abstract class	Common behavior with customization points
Factory	`IdGenerator`	Centralized ID generation
Observer	JavaFX Property Bindings	Real-time UI updates

🔒 Security Features

Feature	Implementation
Role-Based Access Control	`AuthorizationService` checks on every operation
Immutable Transactions	All `Transaction` fields are `final`
Masked Account Numbers	Display as `XXXXXXXXXXXX3456`
Input Validation	Custom validators for all user input
Exception-Driven Security	Custom exceptions for all error scenarios
Audit Trail	Every transaction records employee details
Session Management	`SessionManager` for secure employee sessions
Defensive Copying	Unmodifiable collections returned from repositories

🪟 JavaFX Desktop Application

Screenshots & Features

🔑 Login Screen

Employee authentication
Role detection and display
Secure session initialization

📊 Dashboard

Role-based navigation sidebar
Dynamic content loading
Employee info display
Quick action buttons

👤 Customer Management

Create customer form with validation
Customer list with search
Account count per customer

💳 Account Management

Open Savings/Current accounts
Configurable overdraft limits
Account list with filtering

💰 Transactions

Deposit/Withdraw forms
Real-time fee calculation
Dynamic fee information card
Transaction receipt display
Transaction history with filters
Export to CSV

UI Components

Custom CSS theme (bank-theme.css)
Responsive sidebar navigation
Alert system for feedback
Form validation with visual feedback
Data tables with sorting
Masked sensitive data display

🖥️ CLI Application

Complete console-based workflow:

┌─────────────────────────────────────────┐
│           FINANCE BANK CLI              │
├─────────────────────────────────────────┤
│  1. Login                               │
│  2. Create Customer                     │
│  3. Open Account                        │
│  4. Deposit                             │
│  5. Withdraw                            │
│  6. Transaction History                 │
│  7. Export CSV                          │
│  8. Logout                              │
│  0. Exit                                │
└─────────────────────────────────────────┘

🧪 Automated Testing

Test Coverage

Category	Tests
Authentication	Login success/failure, invalid credentials
Authorization	Role-based access, permission denied
Customer	Creation, validation, duplicates
Account	Opening, validation, types
Transactions	Deposit, withdraw, fees, overdraft
Exceptions	All custom exception scenarios

Running Tests

# Run all tests
mvn test

# Run with verbose output
mvn test -Dtest=BankingSystemTest

# Run specific test method
mvn test -Dtest=BankingSystemTest#testDeposit

Test Isolation

@BeforeEach
void setUp() {
    BankService.getInstance().reset();  // Clean state for each test
}

🚀 Installation

Prerequisites

Java 17 or higher
Maven 3.x
JavaFX SDK 21 (handled by Maven)

Clone & Build

# Clone repository
git clone https://github.com/omar-abdullah-dev/Core-Banking-Backoffice-Java.git
cd BankSystemWIthExceptions

# Build project
mvn clean install

# Run tests
mvn test

🎮 How to Run

JavaFX Desktop Application (Recommended)

mvn javafx:run

CLI Application

# Using Maven
mvn exec:java -Dexec.mainClass="com.finance.bank.app.BankEmployeeCLI"

# Or run directly from IDE
# Main class: com.finance.bank.app.BankEmployeeCLI

Default Test Credentials

Username	Password	Role
`ahmed`	`ahmedPass!`	Manager
`mohamed`	`mohamedPass!`	Teller
`omar`	`omarPass!`	CS

📊 Example Workflow

1. Login as Manager (ahmed/ahmedPass!)
2. Create Customer (Enter valid Egyptian National ID)
3. Open Savings Account for customer
4. Deposit EGP 10,000
5. Withdraw EGP 1,000 (Fee: EGP 10, Total: EGP 1,010)
6. View Transaction History
7. Export to CSV
8. Logout

📌 Project Status

Component	Status
CLI Application	✅ Complete
JavaFX GUI	✅ Complete
Unit Tests	✅ Complete
CSV Export	✅ Complete
Documentation	✅ Complete
Code Quality	✅ Production-Ready

🔮 Future Improvements

Database Integration — MySQL/PostgreSQL persistence
Password Hashing — BCrypt encryption
Spring Boot API — RESTful web services
Web Frontend — React/Angular client
Microservices — Service decomposition
Logging Framework — SLF4J integration
Docker Support — Containerization
CI/CD Pipeline — GitHub Actions

📄 License

This project is open-source and intended for educational purposes.

👨‍💻 Author

Omar Abdullah Moharam

Built with ❤️ to demonstrate clean Java architecture, OOP principles, and production-quality code.

Name		Name	Last commit message	Last commit date
Latest commit History 83 Commits
.idea		.idea
exports		exports
src		src
target		target
.gitignore		.gitignore
BankSystemWIthExceptions.iml		BankSystemWIthExceptions.iml
README.md		README.md
core-banking-backoffice-system.iml		core-banking-backoffice-system.iml
pom.xml		pom.xml

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🏦 Finance Bank — Employee Back-Office System

📋 Overview

🛠️ Tech Stack

✨ Features

🔐 Authentication & Authorization

👤 Customer Management

💳 Account Management

💰 Transaction System

📤 CSV Export System

🇪🇬 Egyptian National ID Validation

🏗️ Architecture

📂 Project Structure

❗ Custom Exceptions

🧠 Design Patterns

🔒 Security Features

🪟 JavaFX Desktop Application

Screenshots & Features

UI Components

🖥️ CLI Application

🧪 Automated Testing

Test Coverage

Running Tests

Test Isolation

🚀 Installation

Prerequisites

Clone & Build

🎮 How to Run

JavaFX Desktop Application (Recommended)

CLI Application

Default Test Credentials

📊 Example Workflow

📌 Project Status

🔮 Future Improvements

📄 License

👨‍💻 Author

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