Patterns
Introduction
With this educational project, I provide implementations of commonly used design patterns.
Below, I first describe the aims I have with the current project. Then, I provide an overview of the design pattern implementations that are currently available. In addition, I provide some background information on the design patterns I focus on in this project.
The release history of this project is contained in the changelog.
1. Aims
My aims with this project are to:
- Build up knowledge of design patterns.
- Learn how these design patterns can be implemented.
More generally, I strive to:
- Gain experience with different programming languages.
- Get to know the specifics of these languages.
Finally, I aim to:
- Showcase this experience and knowledge.
2. Overview
Currently, implementations of commonly used design patterns are available in the following languages:
More specifically, I provide the following design pattern implementations:
| Design pattern | Java |
|---|---|
| Singleton | ✅ |
3. Background
In what follows, I give general information on the creational design patterns I focus on in this project.
3.1 Creational design patterns
3.1.1 Singleton
The singleton design pattern could well be the most well-known design pattern. The basic idea of this pattern is to ensure that there is only a single instance of a particular class. Any attempts to retrieve or create another instance of this class lead to this same object. This object, which could be called a singleton instance, thus, acts as a global.
The use of a global singleton object can be practical in several situations. Think, for example, of an object that should store the global configuration of an application or an object that should manage access to external resources such as databases or files.
It should be noted, however, that the singleton design pattern is often criticized. For one thing, singletons break the single-responsibility principle. Next to the application-related tasks they are given, they are responsible for their creation. Secondly, global objects that persist in time are notoriously hard to test since they may cause (unit) tests to interfere with each other.
For completeness, I do include implementations of the singleton design pattern in this project.
License
Copyright © 2022, 2023 Maurits Silvis
This source code package is subject to the terms and conditions defined in the GNU General Public License v3.0 or later.