Refactoring is a process in programming to improve the design, structure, or implementation of the software, while preserving its functionality. It’s an integral part of agile software development, including Scrum, and a practice particularly encouraged for Certified Scrum Developers (CSD). A programmer can perform refactoring manually or automating the whole process using refactoring tools.
In the context of Certified Scrum Developers(CSD), it’s important to understand refactoring as it forms a crucial part of the Scrum model of software development where the iterative nature of the model requires frequent modifications to the codebase.
Why is Refactoring Important?
Refactoring is crucial for multiple reasons:
- Improves Code Readability and Reduces Complexity: Refactoring makes the source code more readable and understandable. It’s easier for developers to comprehend, read and test the code making the software development process more efficient.
- Finds Bug and Debugs Easier: Refactoring often helps in identifying and fixing hidden bugs in the codebase. Making the codes simpler to understand helps make debugging easier and accurate.
- Extends Software Lifespan and Prepares for Future Changes: By keeping the code clean and organized, refactoring ensures that it can be updated or modified with minimal hassle. This readiness for the future can enhance the lifespan of the software.
Refactoring in Practice
A common example of a refactoring process can be transforming a ‘for’ loop into a ‘while’ loop to enhance efficiency. Here is a small pseudocode for demonstration:
Before Refactoring:
For i=0; i<n; i++
{
if (a[i] = b)
{
print b;
exit;
}
}
After refactoring:
i = 0;
while (i < n)
{
if (a[i] = b)
{
print b;
exit;
}
i++;
}
The after refactoring code is considered more efficient due to denomination in a single string.
In another scenario, suppose you have a large, monolithic function that carries out a series of steps. Such a function is hard to understand and maintain. You can refactor the function by breaking it down into smaller, more manageable functions each of which carries out a single step of the process. This is known as the Extract Method refactoring technique.
Refactoring on a Large Scale
On a wider scale, refactoring can involve restructuring an entire software system to make it more efficient or more adaptable to new functionalities. This act usually occurs under the process known as “redesign” or “rearchitecting”.
Refactoring vs Other Techniques
Refactoring can sometimes be mistaken for other techniques such as rewriting or cleaning code. It’s important to note that unlike these techniques, refactoring is not meant to fix bugs or add new features. Its sole aim is to improve the internal structure of the code while maintaining its external behavior.
Refactoring in Scrum Developers (CSD) Exam
As part of Certified Scrum Developers (CSD) exam content, understanding the concepts and application of refactoring is key to skilled, agile software development. It indicates your knowledge in Scrum framework and agile principles which include coding standards and refactoring.
Practice Test
Refactoring is the process of altering existing code in order to make the source code easier to understand and simpler to modify.
- a) True
- b) False
Answer: a) True
Explanation: Refactoring is a disciplined way to clean up code that minimizes the chances of introducing bugs. In essence, when you refactor you are improving the design of the code after it has been written.
Refactoring changes the underlying behaviour of the software.
- a) True
- b) False
Answer: b) False
Explanation: The primary goal of refactoring is to make the code more understandable and easier to maintain, without changing observable behaviour of the software.
Which of the following are benefits of refactoring? Select all that apply.
- a) Improve code readability
- b) Increase code’s performance
- c) Decrease duplication of code
- d) Apply changes easier and faster
Answer: a) Improve code readability, c) Decrease duplication of code, d) Apply changes easier and faster
Explanation: Refactoring helps to improve the design of software, make it easier to understand, and reduce complexity. This makes the code easier to read, reduces duplication, and makes changes easier to apply.
Which of the following does not denote refactoring?
- a) Reducing software complexity
- b) Improving the design of software
- c) Adding new features
- d) Improving code readability
Answer: c) Adding new features
Explanation: Refactoring is concerned with making changes to the code to make it simpler to understand and easier to modify, not with adding new features to the software.
Improving the performance of the code is the primary goal of refactoring.
- a) True
- b) False
Answer: b) False
Explanation: The primary goal of refactoring is not to improve performance, but to improve the design of the code, readability, and reduce complexity.
Refactoring should be done at the end of the development process.
- a) True
- b) False
Answer: b) False
Explanation: Refactoring should be done as a regular part of everyday programming, not just at the end of the development process.
Refactoring is an important technique for agile development methodologies.
- a) True
- b) False
Answer: a) True
Explanation: In agile methodologies, refactoring is performed incrementally, as a part of each iteration of the software development process.
Refactoring can make a system easier to understand and cheaper to modify.
- a) True
- b) False
Answer: a) True
Explanation: Refactoring is all about making the code more understandable and simpler to change, which ultimately cuts down costs in future modifications.
Is it compulsory to perform testing after refactoring?
- a) Yes
- b) No
Answer: a) Yes
Explanation: Even though refactoring should not change the program’s observable behavior, there’s always a chance of introducing bugs. Therefore, it’s essential to retest the program.
The refactoring process consists of a series of small behavior-preserving transformations.
- a) True
- b) False
Answer: a) True
Explanation: Each transformation (called a ‘refactoring step’) does little, but a sequence of transformations can produce a significant restructuring of the code base.
Interview Questions
What is the definition of refactoring?
Refactoring is the process of restructuring existing computer code—changing the factoring—without changing its external behavior.
What is the main purpose of refactoring?
The main aim of refactoring is to improve the design of existing code, improve its readability, and reduce its complexity to make it easier to maintain and enhance further.
How does refactoring relate to the principles of Agile development?
In Agile, regular refactoring is done to enhance software design, prepare the code for future changes, and improve its overall quality by making it clean and simple.
When should refactoring be performed within the Scrum framework?
Refactoring should be part of daily work. Whenever a piece of code is touched, a developer should leave the code cleaner than it was before.
What are the potential dangers of not refactoring the code regularly?
The consequences of not refactoring are code rot, increased technical debt, decreased code understandability, increased complexity, and eventually, it costs more time to make changes or add new features to the software.
What should a Certified Scrum Developer consider when refactoring?
A Certified Scrum Developer should consider the best practices of design, naming conventions, decisions about modularity, and overall code organization when refactoring.
What are the main steps involved in the refactoring process?
The main steps in the refactoring process are identifying where the software needs augmentation, understanding these areas and any dependencies, making the modifications and testing these modifications to ensure the behavior remains unchanged.
What role does testing play in refactoring?
Testing is crucial to refactoring. Tests must be in place to ensure the system’s functionalities stay the same after refactoring.
Can refactoring result in any immediate improvement in performance?
Not necessarily. The primary purpose of refactoring is to improve code readability and reduce complexity. It could lead to performance improvements, but such improvement is not the primary goal.
How does continuous refactoring improve code maintainability?
Continuous refactoring keeps the code clean, simple, and easy to understand, making it easy to spot defects, implement changes, and ensure long-term maintainability.
What tooling can assist with refactoring?
Integrated Development Environments (IDEs) like Eclipse, IntelliJ, and Visual Studio provide tooling support to automatically refactor code blocks based on best practices.
What is refactoring to patterns?
Refactoring to patterns is about applying pattern-oriented design transformations to improve a system’s design while preserving its semantics.
When should refactoring be avoided?
Refactoring should be avoided when it may not significantly improve the system, when the existing code base is too big or complex to understand and modify accurately, or when there is a lack of sufficient testing.
What principle supports the need for refactoring in Agile Software Development?
The principle “Clean Code That Works” from the Agile Manifesto supports the need for refactoring. It emphasizes on having the code simple, clean, and working at every step of development.
How does the Boy Scout Rule relate to the concept of refactoring?
The Boy Scout Rule states “Leave the campground cleaner than you found it.” In refactoring context, it means that developers should always strive to leave the code cleaner than it was before, incrementally improving the system’s design.
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