Design Pattern on Sven Ruppert

Core Java - Flow.Processor

sven.ruppert@gmail.com (Sven Ruppert) — Thu, 04 Sep 2025 11:27:00 +0000

Reactive streams address a fundamental problem of modern systems: Producers (sensors, services, user events) deliver data at an unpredictable rate , while consumers (persistence, UI, analytics) can only process data at a limited speed. Without a flow control model , backlogs, storage pressure, and ultimately outages occur.

How and why to use the classic Observer pattern in Vaadin Flow

sven.ruppert@gmail.com (Sven Ruppert) — Mon, 01 Sep 2025 11:32:18 +0000

1. Introduction and motivation
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The observer pattern is one of the basic design patterns of software development and is traditionally used to decouple state changes and process them. Its origins lie in the development of graphical user interfaces, where a shift in the data model required synchronising several views immediately, without a direct link between these views. This pattern quickly established itself as the standard solution to promote loosely coupled architectures.

Short links, clear architecture – A URL shortener in Core Java

sven.ruppert@gmail.com (Sven Ruppert) — Tue, 10 Jun 2025 22:43:22 +0000

A URL shortener seems harmless – but if implemented incorrectly, it opens the door to phishing, enumeration, and data leakage. In this first part, I’ll explore the theoretical and security-relevant fundamentals of a URL shortener in Java – without any frameworks, but with a focus on entropy, collision tolerance, rate limiting, validity logic, and digital responsibility. The second part covers the complete implementation: modular, transparent, and as secure as possible.

The Compensating Transaction Pattern

sven.ruppert@gmail.com (Sven Ruppert) — Mon, 12 Feb 2024 12:40:41 +0000

The Bird-Eye View
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A Compensating Transaction Pattern is a technique used to ensure consistency when multiple steps are involved in a process, and some steps may fail. It essentially consists in having “undo” transactions for each successful step, so if something goes wrong later on, you can reverse the changes made earlier and maintain data integrity.

Pattern from the practical life of a software developer

sven.ruppert@gmail.com (Sven Ruppert) — Tue, 09 Mar 2021 21:28:00 +0000

Builder-Pattern
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The book from the “gang of four” is part of the essential reading in just about every computer science branch. The basic patterns are described and grouped to get a good start on the topic of design patterns. But how does it look later in use?
Here we will take a closer look at one pattern and expand it.