TransactionTracker

A command-line personal finance management application built with Java 17. Track your income and expenses, categorize transactions, and monitor your financial balance — all stored locally in JSON format.

Features

• Add & manage transactions — Log income and expenses with full details
• Categorized expenses — Food, Rent, Transport, Entertainment, Healthcare, Utilities, and more
• Income sources — Salary, Freelance, Investment, Business, Gift, and more
• Payment methods — Cash, Credit Card, Debit Card, Bank Transfer, Digital Wallet
• Repeatable transactions — Flag recurring income or expenses
• Tax-deductible tracking — Mark income entries as tax-deductible
• Budget tracking — Flag expenses as budgeted or unbudgeted
• Date range filtering — Query transactions between any two dates
• Balance overview — View total income, total expenses, and net balance
• JSON persistence — Data is saved locally to transactions.json and survives restarts

Tech Stack

• Java 17
• Gradle — Build automation
• Jackson — JSON serialization/deserialization (jackson-databind, jackson-datatype-jsr310)

Project Structure

src/main/java/
├── app/
│   └── Main.java                        # Entry point
├── model/
│   ├── Transaction.java                 # Abstract base class
│   ├── Income.java                      # Income transaction
│   ├── Expense.java                     # Expense transaction
│   └── enums/
│       ├── TransactionType.java
│       ├── ExpenseCategory.java
│       ├── IncomeSource.java
│       └── PaymentMethod.java
├── repository/
│   ├── ITransactionRepository.java      # Repository interface
│   ├── InMemoryTransactionRepository.java
│   ├── FileTransactionRepository.java   # JSON-backed persistence
│   └── dto/
│       ├── TransactionDTO.java
│       └── TransactionMapper.java
├── service/
│   ├── ITransactionService.java         # Service interface
│   └── TransactionService.java
├── handler/
│   ├── TransactionInputHandler.java
│   └── TransactionOutputHandler.java
├── validator/
│   └── TransactionValidator.java
└── ui/
    └── ConsoleMenu.java                 # CLI menu

Architecture

The project follows a layered architecture with clear separation of concerns:

• Model — Domain objects (Transaction, Income, Expense) with built-in validation
• Repository — Data access layer with an interface and two implementations (in-memory and file-based)
• Service — Business logic layer that orchestrates repository operations
• Handler — Input/output handling for the console interface
• UI — Console menu that ties everything together

Dependency injection is used in Main.java, making it easy to swap the repository implementation (e.g. switch to InMemoryTransactionRepository for testing).

Getting Started

Prerequisites

• Java 17+
• Gradle (or use the included gradlew wrapper)

Run the application

./gradlew run

Switch to in-memory storage (for testing)

In Main.java, replace:

ITransactionRepository repository = new FileTransactionRepository();

with:

ITransactionRepository repository = new InMemoryTransactionRepository();

Data Storage

Transactions are persisted to transactions.json in the project root. The file is created automatically on first save and updated after every add, update, or delete operation.