Design Pattern on Sven Ruppert

Advent Calendar - 2025 - Filter & Search – Part 01

sven.ruppert@gmail.com (Sven Ruppert) — Tue, 02 Dec 2025 07:05:00 +0000

With the Vaadin interface described in [Part III], our URL shortener has a fully functional administration console available for the first time. It allows viewing existing short links in tabular form and managing them manually. But after just a few dozen entries, a clear limit becomes apparent: displaying all saved mappings is neither performant nor user-friendly. An efficient shortener must be able to scale – not only when generating, but also when searching through its data.

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.

CWE-778: Lack of control over error reporting in Java

sven.ruppert@gmail.com (Sven Ruppert) — Fri, 18 Oct 2024 14:07:20 +0000

Learn how inadequate control over error reporting leads to security vulnerabilities and how to prevent them in Java applications.
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Safely handling error reports is a central aspect of software development, especially in safety-critical applications. CWE-778 describes a vulnerability caused by inadequate control over error reports. This post will analyse the risks associated with CWE-778 and show how developers can implement safe error-handling practices to avoid such vulnerabilities in Java programs.

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.