Restaurant Bill

A simple Vaadin Flow (v24) web app that helps calculate a restaurant bill: tip amount, bill + tip total, and amount per person when splitting the check. Built with Java 17 and Maven, packaged as a WAR, and runnable locally via Jetty or deployable to Heroku.

Last updated: 2025-10-31

Features

• Enter bill subtotal, tip percentage, and number of people to split between
• Calculates:
  • Tip amount
  • Bill + tip total
  • Amount per person
• Clean Vaadin UI, no JavaScript required
• Unit tests for the calculation service

Tech stack

• Java 17
• Vaadin 24 (Flow)
• Maven (WAR packaging)
• Jetty Maven Plugin for local dev server
• JUnit 5 for tests
• Optional: Heroku deployment using webapp-runner and a Procfile

Getting started

Prerequisites

• JDK 17 installed and on PATH
• Maven 3.9+ installed and on PATH

Clone

git clone https://github.com/your-org-or-user/RestaurantBill.git
cd RestaurantBill

Run locally (dev)

This project uses the Jetty Maven Plugin. The first run may take longer as Vaadin prepares the frontend.

mvn -DskipTests jetty:run

Then open:

• http://localhost:8080

To stop the server, press Ctrl+C in the terminal.

Build

• Development build (no production optimizations):

mvn -DskipTests clean package

Produces target/restaurantbill-0.1.war.

• Production build (minified frontend, no dev tools):

mvn -Pproduction -DskipTests clean package

Run tests

mvn test

How it works

Core logic lives in BillCalculationService, which computes three values from inputs on the Bill model:

• Tip amount = billTotal * tipPercent / 100
• Total with tip = billTotal + tipAmount
• Amount per person = totalWithTip / numberOfPeople

Key files:

• src/main/java/com/reedmanit/restaurantbill/service/BillCalculationService.java – calculation logic (rounds to 2 decimals)
• src/main/java/com/reedmanit/restaurantbill/model/Bill.java – holds bill fields (Vaadin NumberFields)
• src/main/java/com/reedmanit/restaurantbill/view/BillForm.java – the UI form
• src/main/java/com/reedmanit/restaurantbill/MainView.java and AppShell.java – Vaadin view and shell
• src/test/java/com/reedmanit/restaurantbill/service/BillCalculationServiceTest.java – unit tests

Project structure

RestaurantBill/
├─ pom.xml
├─ Procfile
├─ system.properties
├─ src/
│  ├─ main/
│  │  ├─ java/com/reedmanit/restaurantbill/
│  │  │  ├─ model/
│  │  │  ├─ service/
│  │  │  └─ view/
│  │  ├─ resources/
│  │  └─ webapp/
│  └─ test/
└─ README.md

Heroku deployment (optional)

This repo includes a Procfile, system.properties, and Maven setup to fetch webapp-runner. Two common options:

1. Deploy with Git (Heroku Java buildpack)

• Install Heroku CLI and log in

heroku create
heroku stack:set heroku-22
git push heroku main

Heroku will build and run the app using the Procfile.

2. Deploy with Maven plugin The POM includes com.heroku.sdk:heroku-maven-plugin.

mvn heroku:deploy

Troubleshooting

• If the first jetty:run is slow, it’s likely Vaadin preparing the frontend. Subsequent runs are faster.
• If the browser shows a 404, verify Jetty is running and you’re opening http://localhost:8080/.
• On Windows PowerShell, you can run the same Maven commands shown above.

License

This project is licensed. See the LICENSE file for details.

Contributing

• Fork the repo, create a feature branch, and open a PR.
• Please add or update tests for logic changes.

Acknowledgments

• Vaadin team and community for the excellent web components and Flow framework.