In order to design software, developers must first understand the task at hand (the business need), break the task down into its component parts, and decide how to address each component. Once this is completed, the developers can decide how all of the components should assemble together in order to produce the desired functionality. CampaignDrive engineers, over the last ten years, have developed a set of five software design principles that we have found to streamline the design process successfully.
Software Design Principles are guidelines used to help organize, construct, and engineer the components of code. Planning how to structure code before implementing it is critical, as it will increase the likelihood of a robust, flexible, testable, and scalable component (or system). Studying these design principles will help developers avoid the traps and pitfalls engineers have struggled with for years in software design. Following good design principles puts the developer a step ahead, long before a single line of code is written.
Following are five of the most important design principles:
5 Software Design Principals to Keep Development on Track
1. Simplicity
Code should be written clearly and with simple structure. If code is not simple, it overcomplicates testing, debugging, and maintenance of the code. Simplicity also means that other developers can quickly understand the intricacies and complexities of the code with minimal time and effort. Some attributes of clear, simple code are:
- Well named variables, using agreed upon naming conventions
- Clearly formatted code
- Short cohesive functions, classes, and modules
- Decoupled code
2. Testability
Testing is an essential factor when it comes to ensuring the software does what it’s designed to do, and to consider how it may be improved. For this reason, there are two factors in determining the quality of the software from a testability perspective:
- The software can easily be tested
- The test code is written to test that the software does what it is designed to do
Software isn’t static, it is constantly updated as it evolves, in order to meet users’ demands. Testing is required on a continuous basis, and it should support maintenance over time.
3. Don’t Repeat Yourself
Avoid redundant code as replication spread across codebase makes it hard to change, update, and debug code.
4. Minimalistic
Code should reflect the functionality that is required, and not account for future ‘possible’ functionality. ‘Extra’ code only makes the code hard to test, maintain, extend, and comprehend, as well as a waste of the most valuable resource - your time.
5. The SOLID Principles
“SOLID” is an acronym for software design principles, where each letter represents one of the following principles:
- Single responsibility - every module or class should have responsibility over a single part of the functionality provided by the software and that responsibility should be entirely encapsulated by the class.
- Open-closed - software entities should be open for extension, but closed for modification.
- Liskov substitution - the inherited class should complement, not replace, the behavior of the base class.
- Interface segregation - no client should be forced to depend on methods it does not use.
- Dependency inversion - developers should work at the interface level and not at the implementation level.
Achieve Software Design Success
When applied simultaneously, these five principles help a developer create code that is easy to maintain and extend over time. When these principles are applied, software becomes flexible, maintainable, allows for added features, algorithm changes, and new integrations with ease.
This is only a short introduction to some of the software design principles developers should adhere to. For further reading, I recommend Web Scalability For Startup Engineers by Artur Ejsmont. These software design principles have guided our development team to great software and a seamless enhancement process for upwards of 10 years! With steady practice and adherence, these principles make a huge impact on a developers’ code quality.
For more about our development team and processes over at CampaignDrive, check out Agile Methodologies and Scrum: The Who, The Why, and The How.
