Common Software Design Patterns: 6 Examples and Their Uses

Common software design patterns have always served as excellent time-saving tools for developers and designers to make more informed design choices that benefit the end user. The best thing about these solutions is that they are not rigid in their applications- they are just frameworks tested across different designs and help bring the ideal design to life while staying true to the original idea.

Any experienced designer can pick out the pattern within a published design since these patterns have recurring features that are easy to identify. In addition, the ideas are open-source, allowing new applicants to improve upon the previous pieces with their fresh creative designs.

If you want to construct the ultimate product design to help your idea stand out, this article will take you through 6 common patterns used across the design industry. To help you make better design choices, we will also review why these design patterns are crucial for object-oriented programming and professional designers!

Why are software design patterns important?

Common software design patterns are an extension of the concept of OOP programming (object-oriented programming). Object-oriented designs are extremely popular with modern designers as they help shape creative solutions that efficiently fulfil user needs. Furthermore, with the best practices and layout structures, these OOP design approaches are much easier to create, test, implement and reapply.

When a design idea is proposed, it usually has a shape in the designer’s head, and if they proceed without using a fixed pattern, it could contribute to a messy final result with no set tones. However, in reality, most designs usually follow a pattern in some way, so it is essential to learn the differences between the popular types and avoid overusing one that complicates your final product.

Common software design patterns are unpopular with some individuals mainly because of misconceptions that they are challenging to learn and apply. However, there is no doubt that the correct application of a design pattern can elevate product designs, making them a must-have for developers, programmers and, of course, software designers. They are particularly important when design and development are carried out as a team since they make understanding common issues and their workarounds easier.

Another benefit of using design patterns is that they present an overall solution that does not specifically cater to one type of issue, making it easier to modify and work with large-scale and smaller-scale concepts. If you want to learn more about the impacts of digital transformation on businesses, consider looking at this guide!

What are six common software design patterns?

Some popular design patterns used to help efficient design processes are the Builder pattern, the Observer pattern, the Façade pattern, the Command Design pattern, the Strategy pattern and the Singleton pattern. 

In the following sections, we will explore each of these in detail, including their specific uses and the misconceptions around them:

The Builder Pattern

This particular design pattern enables the designer to analyse the object construction from every angle, thus allowing a greater command over the steps involved in the overall design process. 

This pattern allows the software designers to utilise the fundamental construction code to decouple, maintain and support several representations of the main object. Furthermore, this pattern works methodologically, executing each part of the construction as individual steps, starting from the fundamental base and moving on to newer recapitulations for the constructed object without overlapping actions.

It is a novice mistake to confuse this pattern for the abstract factory pattern, and most confusion stems from a need for proper education on what separates the two. It is essential to remember that they are fundamentally different concepts, and one of the main ways you can distinguish them is by noting that the builder design pattern executes all the steps in an organised and sequential way, only moving to the next stage after the previous one has been fully completed. 

On the other hand, the abstract factory method does not construct the objects in this manner. Instead, it works more directly and completes the object in a single round by doing the opposite of the former pattern. To learn about the differences between software engineers and developers, look at our detailed guide on the topic!

The Facade Pattern

Just like the builder design pattern is “creational”, the façade pattern is labelled as a “structural” one because it works with several complex interfaces that are usually sub-systems embedded into the larger framework and organises them into one single large body of coded objects. As a result, different objects within the smaller systems can be easily accessed through the constructed interface.

True to its name, the façade pattern creates an interface that is simpler and more attractive to disguise the vast network of sub-systems and minor elements from a client, making the software easier to use and interact with. By using this particular design pattern, developers can work with various complicated frameworks and software libraries to make their designs easier to access.

This pattern also allows the separation of different code systems, particularly isolating outside code from the workings of the internal frameworks. In the example of the e-commerce sector, this kind of software design will save customers the hassle of navigating to every different microsystem behind a purchase and allow them to interact with the brand with an easy-to-use interface that is straightforward in its purpose.

Therefore, this kind of software design enables the client to get through the process and take the necessary actions without being dragged into the complexities of the systems that are holding things together behind the scenes.

The Observer Pattern

Observer design patterns are excellent if your end product comprises components that must behave a certain way depending on exterior influences, inputs or actions. With this pattern, the subject linked to dependents (or observers) is informed whenever any of these observers go through any change.

This pattern revolves around a subject that may have many dependents or observers at any time, resulting in a one-to-many system. Since all actions are event-driven, companies can create excellent designs to keep their clients in the loop with common actions. 

However, it is essential to remember that an observer is not bound to a single subject and may also choose to sign up for updates on other topics. For example, a social media page, which could be an example of a subject, might be something a client subscribes to receive news feed updates. Therefore, whenever the page publishes a new post, the subscriber will see it.

Some downsides of using this pattern are the unnecessary expenses when you implement it in a product with limited objects/users, its effects on product complexity and data security issues.

That being said, when working with the observer design pattern, the essential part is making an accurate decision about the chain of dependency and the overall hierarchy within the framework.

The Strategy Pattern

As another pattern from the behavioural group, this pattern equips a company with different strategies to control its product’s operations, with different pre-programmed algorithms for different scenarios. It starts by understanding the core set of actions that make up a process, and after that, it creates a system to slightly alter the results based on user input. Therefore, this pattern is put into practice after the “behaviour” of the client has been analysed and recorded.

A software designer can put related algorithms into groups using this particular pattern. Doing so allows them to isolate each algorithm into various classes, also known as strategies, and then swap their objects without changing the primary client. Based on the chosen system, a class behaviour or algorithm can be easily altered at runtime in this approach.

The pattern recognises the user’s actions and inputs, then attempts to craft a personalised experience that meets their needs. Since it means putting the user first, this design pattern is ideal for personalising marketing tactics efficiently.

The Command Design Pattern

The main focus of a command software design pattern is how various classes and objects within an existing framework interact with one another. This pattern aims to identify performance loopholes in product designs and rectify them by turning a user request into a separate object. Doing so limits mutual behaviour, and once a request has been fulfilled, different options can be provided to the end-user to guide them through a process.

Implementing this pattern has several advantages, including better functionality and performance, establishing command queues, and rolling back on executing requests if the user decides not to proceed. However, it is essential to be diligent when using this pattern since you will be working with multiple classes, and it is necessary to write clean code with no similar class names.

If you wish to create a product setup where commands and requests are independent of monitoring, this is the correct pattern for you!

The Singleton Pattern

The “creational” pattern that we discussed previously also includes the singleton design pattern, which is a system that limits the creation of objects for a class to only one instance while at the same time granting universal access to a global variable. 

In an office setting, it is more practical to have a single printer that everyone can use compared to setting up multiple printers for each user or new instances for each user who needs to print a document, which would be highly inconvenient.

The only downside with these patterns is how they lock objects in one place while you work through the pattern rules. This makes it difficult to test, revise and change design decisions later, but singleton patterns are still quite popular and often seen in various products.

Conclusion

While one design pattern could be perfect for representing your creative ideas, choosing the wrong pattern can destroy your original idea. There are also disadvantages of being overly reliant on design patterns, but practice, consistency and patience will help you use these powerful tools to your benefit. 

If you want to expand into a career in software engineering and design, either as a professional or start as a new student, get in touch with one of our experts by booking a career consultation and upskill with the right plan!