Code Refactoring Techniques in Agile

Refactoring simply means restructuring a piece of code to improve the operation without altering its functionality. But, what is refactoring in Agile? In Agile, refactoring means missing or not missing an iteration deadline.

So what is code refactoring in Agile? It is a practice where the software’s source code is altered without its inherent behavior. In simpler terms, it is a practice that solely focuses on getting the code into a more desirable state for the development team. It is important to note that refactoring code is not:

1. Fixing any bugs
2. Improve or change the aspects of source code such as the software’s interface
3. Rewriting code

One might ask, isn’t it better just to go ahead with the code without any refactoring which takes extra effort and time. To answer it simply, no. One can argue that it is the single most important practice for having success with Agile adoption. Every time there is a change in the code without refactoring, the code got frustrated and costs a lot of time.

As the project progresses, the code becomes more complicated harder to maintain, understand, and change. Refactoring the code helps avoid all these problems. As the software grows in size and complexity and evolves, refactoring allows one to modify it constantly as an answer to the inevitable change.

Before jumping on to the refactoring methods in Agile, let’s see the  uses of the refactoring process:

1. Code refactoring is mainly used to “uncomplicated” huge codes and it is always advisable to carry out the code refactoring in a series of small changes. Each small change should make the existing code slightly better, leaving the function of the program or software in working condition.
2. When refactoring, there is a potential for bugs to be introduced into the program if you do not run tests. Therefore, it is a must to use TDD and CI to run tests after every small step of refactoring the code.
3. When refactoring, the code must become cleaner. It’s a basic tip but very effective. 
4. Refactoring can often be confused with adding new functionality. The processes look similar but, it is of utmost importance that creating a new function and refactoring is separated. Adding new functions can be done at the development stage but, the refactoring stage must be only about cleaning the codes without changing any inherent properties or behavior of the program.

Code refactoring has a lot of benefits, some of which are listed below.

1. You get to see the whole picture

Breaking a single method into several less complex, easier steps is better. Code refactoring helps you do this exactly. How does it help? When there are several smaller methods, it’s easy to have an eye on everything that’s going on and it becomes easier to manage the program.

2. Make it easy for your team

Think in the long term and make the refactored code such that your co-workers and peers can easily read the codes.

3. Maintaining the program becomes easier

Making changes and updating is a continuous process; there is no escaping it, and it should be welcomed. When the program's codes are not maintained, made easier, or built on a proper foundation, developers are not so keen on making changes. Code refactoring makes it easier to clean up the code, organize it, and make it easier for the developers. Codes built like this are more likely to adapt to changes in the future.

4. Efficiency

Refactoring might be seen as a waste of money and time, but it’s all worth it. At the development stage, problems and time waste are significantly reduced, and every process thereafter becomes highly efficient.

5. Reduces complexity

The main goal of code refactoring is to reduce the complexity of the program’s code. Refactoring is perfect for this since it makes the program cleaner and easier for peers and the development team to understand.

Code Refactoring Techniques

Several refactoring techniques in Agile helps in adopting the correct way of using code refactoring. The following techniques are the most common and useful ones:

1. Red-green refactoring

This technique is the most popular one and forms the basis of all the other techniques. This technique is widely used in Agile software development and is based on Test Driven Development (TDD). It follows a “test-first” approach for design and implementation. This technique incorporates refactoring into a test-driven development cycle. The process starts with a failing “red” test then writing the most straightforward code possible to pass the test “green.” Finally, the code is improved and enhanced, keeping the code test “green”.

The technique is easy to understand, and refactoring blends seamlessly into the overall development process. This technique is so popular and works towards making the overall source code cleaner and easier to manage.

There are two separate parts to this: writing the code to add a new function to the program and improving the code of this function. It is important to understand that both of these parts shouldn’t be done simultaneously.

2. Preparatory refactoring

A developer can make a few changes to the code base so that building the next set of features becomes easier. This technique of code refactoring is called preparatory refactoring, as explained by author Mark Fowler in his book Refactoring: Improving the Design of Existing Code. 

This is done when a developer notices a need for refactoring in the program's code. Although this technique sounds exactly like the Red-green technique, it is slightly different in execution. In this technique, the refactoring process is part of the overall software update but not a separate process.

By noticing that the code needs to be updated, the developer reduces the problems or technical difficulties that might arise later in the project.

If explained via illustration, Jessica Kerr explains this technique.

“It’s like I want to go 100 miles east but instead of just traipsing through the woods, I’m going to drive 20 miles north to the highway, and then I’m going to go 100 miles east at three times the speed I could have if I just went straight there. When people push you just to go straight there, sometimes you need to say, ‘Wait, I need to check the map and find the quickest route.’ The preparatory refactoring does that for me.”

3. Refactoring by Abstraction

Refactoring by abstraction is usually done when the amount of codes to be refactored is huge. The abstraction process involves hierarchy, class inheritances, and extraction. The main goal of the abstraction is to reduce duplicated software codes.

Pull-Up/Push-down is one example of the abstraction process. These are two opposite forms of refactoring involving classes. The Pull-up method pulls the code parts into a superclass to eliminate code duplication. The Push-down method pushes down the code parts from the superclass to the subclasses.

Few other examples include extract subclass, extract interface, extract superclass, collapse hierarchy, replace delegation with inheritance, replace inheritance with delegation, etc. In this technique, the basic idea is to build an abstraction layer that wraps the part of the program that has to be refactored and the counterpart that will eventually replace it.

4. Composing method of Refactoring

This technique's goal is very similar to the abstraction method: simplifying the code to reduce code duplications. Multiple processes, such as extraction and inline methods, can be used to accomplish this.

Extraction involves breaking down the code into smaller bits to find and “extract” the fragmentation. Then, the fragmented code is moved to a separate method. Extraction can have class, interface, and local variables too.

The inline method is a way to reduce the number of unnecessary methods by simplifying the code with refactoring.

5. Simplifying method Refactoring

The code and conditionals in the code tend to get more complicated in their logic over a while. It makes sense to go in and simplify a lot of this. This can be done in a variety of methods such as consolidation of conditional fragments and expressions and replacing the conditional with polymorphism. The simplifying method involves tweaking the interaction between classes.

There are multiple methods you can use for preparatory refactoring. The one that works best will depend on the solution, time frame and the number of people there are to assist the team. One can find many more refactoring techniques in Agile in the book Refactoring: Improving the Design of Existing Code by Mark Fowler.

Code refactoring is like cleaning and organizing the kitchen. It makes everything easy to find, the environment stress-free, and the whole process a lot more efficient.

Also, Check:how to build an agile team

Conclusion:

In conclusion, code refactoring plays a pivotal role in Agile software development, serving as a fundamental practice for maintaining code quality and facilitating iterative improvement. By restructuring code without altering its functionality, Agile teams can ensure that their software remains adaptable, maintainable, and scalable throughout the development process. Refactoring techniques such as Red-green refactoring, Preparatory refactoring, Refactoring by Abstraction, Composing method of Refactoring, and Simplifying method Refactoring enable teams to systematically enhance code readability, reduce complexity, and eliminate duplication. These techniques not only contribute to more efficient development workflows but also promote collaboration and long-term success in Agile projects. Enhance your Agile skills further with Simpliaxis' Extreme Programming Practitioner Certification Training, empowering you to excel in Agile projects and drive innovation in software development