Practical Uses for Design Patterns

Sometimes completing assignments can become monotonous. I think that I find this mainly happens when I cannot seem to think of a practical use for what I am currently working on. While I understand that many of the example implementations of design patterns are intentionally left abstract so as to highlight the importance of the pattern rather than the complexities of the underlying system, this bores me. My approach to programming is often utilitarian in the sense that I want to know how what I am currently working on is going to make someone’s life easier.

(Image source: https://drquicklook.com/products/usb-to-sd-card-adapter)

This week I listened to Episode 30 of the Coding Blocks podcast, from July 26, 2015. In the episode, Allen, Joe, and Michael discuss the Adapter, Facade, and Memento design patterns. The first pattern that was discussed was the Adapter pattern. I paid particularly close attention to this pattern, as I will be researching and compiling an informative piece on the Adapter pattern in the coming weeks. The podcast provided a link to an excellent tutorial on TutorialsPoint, which I will most definitely be using as a reference for my project research. The real-life example used to describe the Adapter design pattern was that of the SD-card adapter, which takes the SD card and adapts, through the use of an interface, to a USB cable that the computer can recognize and use. The Adapter design pattern implemented in software provides a very similar function by taking two otherwise incompatible interfaces and acting as a bridge between them so that they may seamlessly interact with one another.

In the discussion of the Facade design pattern, I saw some parallels to the Adapter pattern but there were certainly also observable differences. The Facade patterns aims to hide the complexities of some underlying system by providing a simplified interface through which the user can gain access and use the resources provided by the system. The example that the three discuss that I found very interesting was transactional payment processing systems such as PayPal. The goal of applying Facade in this case would be to hide multiple repeated calls to APIs that must be completed each time a user would like to perform a task such as setting up a secure connection, passing a token, storing a token, etc. before actually accomplishing the desired task.

The final pattern that is discussed is the Memento design pattern. While the three seem to have mixed feelings about the usefulness of the Memento pattern, I thought that the discussions regarding Megaman and System Restore’s implementation of this pattern were extremely useful and interesting examples. The pattern, in a basic sense, aims to save a complete copy of the state of the object at any given time. This state object is accessed and maintained by two classes – a caretaker and an originator.

What I like most about the examples and explanations that the three give for their respective design patterns is how practical they seem. While the ultimate goal of applying a design pattern to a particular problem is to simplify the overall implementation, it is certainly not always a simple task to apply a pattern. Understanding some of the motivation behind why applying the design patterns makes an implementation cleaner and more effective satisfies my utilitarian inclinations. I am looking forward to exploring the complexities of the Adapter pattern more thoroughly in the near future.

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