Invoice Generator

A Java-based invoice generator that accepts user inputs and generates professional invoices in both text and Excel formats.

Features

• Interactive Console Input: Easy-to-use command-line interface for entering invoice data
• Multiple Output Formats: Generate invoices in text (.txt) and Excel (.xlsx) formats
• Professional Layout: Clean, professional invoice templates with proper formatting
• Sample Data: Generate sample invoices for demonstration purposes
• Flexible Configuration: Customizable tax rates, company information, and invoice notes
• Automatic Calculations: Automatic calculation of subtotals, taxes, and totals
• No-Maven Option: Run text-only version without installing Maven

Available Versions

Text-Only Version (No Dependencies)

• Runs with just Java installed
• Generates professional text-format invoices
• Perfect for quick testing and basic use
• Uses InvoiceGeneratorTextApp class

Full-Featured Version (Requires Maven)

• Supports both text and Excel formats
• Requires Apache POI library for Excel generation
• Uses InvoiceGeneratorApp class
• Professional Excel spreadsheets with formatting

Requirements

• Java 11 or higher
• Maven 3.6 or higher

Project Structure

src/main/java/com/invoicegen/
├── InvoiceGeneratorApp.java          # Main application class
├── model/
│   ├── Invoice.java                  # Invoice data model
│   ├── Customer.java                 # Customer data model
│   ├── Company.java                  # Company data model
│   └── InvoiceItem.java             # Invoice item data model
├── generator/
│   ├── InvoiceGenerator.java        # Generator interface
│   ├── TextInvoiceGenerator.java    # Text format generator
│   └── ExcelInvoiceGenerator.java   # Excel format generator
├── input/
│   └── ConsoleInputHandler.java     # Console input handler
└── util/
    └── SampleDataGenerator.java     # Sample data utility

Dependencies

• Apache POI: For Excel file generation
• JUnit: For testing (development)

Building the Project

1. Make sure you have Maven installed
2. Navigate to the project directory
3. Run the build command:

mvn clean compile

Running the Application

Quick Start (Windows - No Maven Required)

For immediate use without setting up Maven:

Generate Sample Invoice

run-sample-simple.bat

Generate Custom Invoice (Interactive)

run-simple.bat

Note: These scripts generate text-format invoices only. For Excel support, use the Maven approach below.

Full Featured (Maven Required)

Generate Custom Invoice (Interactive)

mvn exec:java -Dexec.mainClass="com.invoicegen.InvoiceGeneratorApp"

Generate Sample Invoice

mvn exec:java -Dexec.mainClass="com.invoicegen.InvoiceGeneratorApp" -Dexec.args="--sample"

Using Compiled JAR (Maven)

Build the JAR file

mvn clean package

Run the JAR

java -jar target/invoice-generator-1.0-SNAPSHOT.jar

Run with sample data

java -jar target/invoice-generator-1.0-SNAPSHOT.jar --sample

All Available Scripts (Windows)

• run-simple.bat - Text-only interactive mode (no Maven)
• run-sample-simple.bat - Text-only sample invoice (no Maven)
• run.bat - Full featured interactive mode (requires Maven)
• run-sample.bat - Full featured sample invoice (requires Maven)

Usage Guide

Interactive Mode

When you run the application in interactive mode, you'll be prompted to enter:

1. Invoice Information:

   • Invoice number
   • Invoice date (or use today's date)

2. Company Information:

   • Company name
   • Address details
   • Contact information
   • Website and Tax ID (optional)

3. Customer Information:

   • Customer name
   • Address details
   • Contact information

4. Invoice Items:

   • Description
   • Quantity
   • Unit price
   • (Add multiple items, press Enter with empty description to finish)

5. Additional Settings:

   • Tax rate (default: 10%)
   • Notes (optional)

6. Output Options:

   • Choose format: Text, Excel, or Both
   • Specify output directory

Sample Mode

Running with --sample generates a pre-configured invoice with sample data, demonstrating all features of the application.

Output Files

The application generates invoices with timestamps in the filename:

• Text Format: invoice_[number]_[timestamp].txt
• Excel Format: invoice_[number]_[timestamp].xlsx
• Sample Files: sample_invoice_[timestamp].txt/xlsx

Invoice Template Features

Text Format (.txt)

• Clean ASCII layout
• Properly aligned columns
• Professional header and footer
• Detailed item breakdown
• Tax calculations

Excel Format (.xlsx)

• Professional spreadsheet layout
• Formatted cells with borders
• Currency formatting
• Styled headers
• Proper column sizing

Example Invoice Content

Both formats include:

• Company letterhead information
• Customer billing details
• Itemized list of products/services
• Subtotal calculations
• Tax calculations
• Final total
• Payment terms
• Optional notes

Customization

You can easily customize:

1. Tax Rates: Modify the default tax rate or enter custom rates
2. Invoice Templates: Edit the generator classes to change layout
3. Company Defaults: Modify SampleDataGenerator.java for default company info
4. Output Formats: Extend InvoiceGenerator interface for new formats

Error Handling

The application includes robust error handling for:

• Invalid date formats
• Invalid numeric inputs
• File I/O operations
• Missing directories (automatically created)

Development

Adding New Features

1. New Output Formats: Implement the InvoiceGenerator interface
2. New Input Methods: Create classes similar to ConsoleInputHandler
3. Additional Fields: Extend the model classes as needed

Testing

Run the test suite:

mvn test

License

This project is open source and available under the MIT License.

Support

For issues or questions, please refer to the source code documentation or create an issue in the project repository.