I'm Alexander Liggesmeyer

Pi4J is intended to provide a friendly object-oriented I/O API and implementation libraries for Java Programmers to access the full I/O capabilities of the Raspberry Pi platform. This project abstracts the low-level native integration and interrupt monitoring to enable Java programmers to focus on implementing their application business logic. I am part of the Pi4J core team.

CocktailPi is not only a piece of software. It’s a cocktail-mixing-machine, that works with a Raspberry-Pi, that controls multiple pumps, which have different ingredients assigned. CocktailPi provides a UI, that can be accessed via web browser. Admins can create other users and assign them to multiple roles with different permissions. Users can create and edit cocktails. Recipes can be ordered if all required ingredients are available. Cocktails can be categorized and shared with other users.

‚Battleships‘ was a student project that I developed with a team of three students as part of the course ‚Entwicklung verteilter Anwendungen‘ (Development of distributed applications) at the University of Applied Sciences in Kaiserslautern.
The project was an implementation of the popular game ‚Battleships‘, where two players try to sink each other’s ships.
The application consists of two parts: a server that acts as a middleman and a client that connects to the server.

Additional features:

• Player-accounts are stored in a SQLite database. Passwords are encrypted.
• Packets are validated server-side.
• Multiple games can be played concurrently.
• Error detection is implemented, for example, if a player loses their connection to the server.
• An in-game chat
• Rematch functionality

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During my studies at the University of Applied Sciences Kaiserslautern, I had a student job at the faculty of Computer Sciences and Microsystems Technology. Along with other students and my professor, Prof. Dr. Bastian Beggel, I worked on a web application that allowed students to learn SQL. The application allowed students to solve exercises that contained ‚SELECT‘, ‚CREATE TABLE‘, ‚UPDATE‘, and ‚DELETE‘ statements. A bonus point and achievement system were implemented to motivate students to complete their exercises.

I developed the following parts of the project:

• Achievement and bonus point system (backend)
• Automatic achievement description generator (backend)
• Global achievement ranking between users (backend)
• Achievement editor (frontend & backend)
• Exercise, scenario, and group editor
• User request WebSocket refactoring
• Vue-router for exercises
• Exam evaluation system (including encryption of all data that belongs to an exam and decryption per password)
• Query-rule system to ensure that students couldn’t solve specific exercises using another method than the expected one (backend)
• External registration and verification system (frontend & backend)
• Create table exercises (backend)
• Performance improvements by delegating multiple tasks to different threads (backend)

The DB-Coach is a single-page application programmed with Vue.js and a Java backend based on the Spring framework

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RateMe is a single-page application that I developed in one of my classes at the University of Applied Sciences Kaiserslautern. It allows registered users to rate pubs and restaurants in and near the city of Zweibrücken. Ratings consist of a grade (in stars) between 1 and 5, a text description, and an optional image. The website does not use any frameworks, and it has been coded using basic JavaScript, HTML, and CSS. The application uses a Java backend that provides the required REST endpoints, which have been implemented using the MicroProfile framework and the OpenLiberty server. The entire application can be started using Docker and configured using environment variables or manually by starting the server.

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AdvancedRegionMarket is my first Java project. It is a plugin for the Minecraft server API called Spigot, which allows server admins to sell or rent in-game regions to players using in-game currency. To achieve this, AdvancedRegionMarket integrates with WorldGuard, which defines regions, WorldEdit, which is used to restore regions, and Vault, which provides an API to communicate with in-game currency plugins.

The plugin consists of around 30,000 lines of Java code, has been downloaded more than 100,000 times, and has an average rating of 4.93 out of 5 stars.

In 2020 I got the scholarship Deutschlandstipendium in cooperation with Empolis.

In 2019 I got the scholarship Deutschlandstipendium in cooperation with Empolis.