What is an Application Design Pattern?

Application Design PatternIf you’re starting to learn programming, you may have read or heard other programmers talk about an application design pattern, and this concept is one of the most important areas of software engineering. Design patterns allow programmers to quickly solve common problems without having to devise a completely original solution every time. There are different levels of design patterns, and solutions range in scope from single statements of code to entire applications. Using patterns in application development is like using a framework or a template, and all types of professionally developed software use patterns of some kind.

When Are Design Patterns Used?

The most common patterns relate to the user interface and user input events, and perhaps the most well-known architectural pattern is the model-view-controller pattern that separates data, graphical user interface and controller code into layers of abstraction, according to W3 Schools. In MVC architecture, the model refers to the data, usually an SQL database; the view refers to the GUI, usually a website template written in HTML, CSS and JavaScript; and the controller refers to the code that responds to user input events, queries the database and sends data to the view, acting as the middleman between the other two layers. This pattern is used in virtually all websites that consist of software that reacts to user input events, as opposed to static sites that simply display HTML-coded information. Not all websites store information in a database, though, and many simpler sites just use JavaScript to respond to input events.

Other common architectural patterns include event-driven architecture, peer-to-peer architecture, presentation-architecture-control and model-template-view. Additionally, many less common patterns, such as transactional reporting, dimensional data modeling, data extraction transformation and loading, data warehouse, operational data store and blackboard system architecture, are used in science and business applications. Oftentimes, patterns are combined to solve multiple problems simultaneously, such as event-driven architecture combined with MVC or peer-to-peer architecture.

How Patterns Make Software Development Easier

The goal of software engineering is to make the programmer’s job as streamlined and efficient as possible, and code reuse is a big part of that goal. Patterns don’t necessarily allow programmers to reuse code, but they allow programmers to design every program with similar code for handling the different parts of the application, such as audio, graphics, physics, networking, data and any other functions a program has. A programmer who writes games for mobile devices can write a framework that handles all of these separate elements of the game so that all that is needed for each new program is to write game-specific logic and drop in the graphical and sound assets.

Using patterns to solve programming problems helps make software development easier to understand, which is why many programmers follow the convention over configuration paradigm, a philosophy that states that programmers should follow conventions rather than waste time customizing and configuring their projects, according to Microsoft. Following conventional design patterns is simply the way professional software is made, and every program should be approached with the strategy of finding a pattern that fits the design goals. Otherwise, there are likely to be many bugs that are hard to fix.

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As people increasingly turn to the Internet and mobile devices to get information and connect with others, software development becomes more and more important. If you have an interest in writing code, continue learning about the all-important application design pattern.