Haven't I Seen You Somewhere Before?
01 Dec 2022Déjà Vu
As you continue doing coding problems and projects, you’ll start to notice recurring techniques that you use. The issues covered may not be related in any way, but the code you implement tends to look similar in structure. These are called design patterns.
Design patterns are reusable solutions on how to solve a common problem when designing an application. It is a template or description on how to approach the problem. These patterns are meant to save time and improve efficiency.
Application of Design Patterns
The final project for my software engineering class required us to create a working application using Meteor. We started with a basic meteor template and implemented our own changes from there. My group was able to make use of design patterns when designing our web application, No More Ramen.
Observer Design Pattern
This is a behavioral design pattern that defines how to notify objects of changes to other object(s). The pattern consists of two actors: the observer (interested in the updates) and the subject (generates the updates).
In the case of our project, this could be seen through the use of subscribers and publishers, which took on the roles of observer and subject respectively. We could subscribe to publications that retrieved data from the MongoDB collections, these also updated the data whenever changes were made. For example, if a student wants to see the recipes available, we would publish the Recipe collection on the server side and then subscribe on the client side so the data can be displayed to the student.
This was also implemented through our use of reactive data. When a MongoDB collection is updated, the code referencing a cursor in that collection will be re-run.
Singleton Design Pattern
This is a creational design pattern that restricts object creation for a class to only one instance. In our project, this comes in the form of the single instances of our collections. For example, the variable “Ingredient” is the singleton instance of the IngredientCollection class.
Design Patterns to the Rescue
Thus, by recognizing these design patterns, we were able to save a lot of time and energy when creating our application. Understanding when and how to apply these patterns is important in software development.
