Insights

What is Code Refactoring in Agile? Benefits, Techniques, and Best Practices

  • Manish Garg
  • By  Manish Garg
  • |
  • 87D32530-FD6E-468E-BB24-045278513D21 Created with sketchtool. 8 MIN READ
  • |
  • 6BCC25D0-42B3-420B-8C28-C5D7EF3F6856 Created with sketchtool. Updated: May 20, 2021

Software developers often rely on a “quick and dirty” approach towards coding to facilitate fast shipping. However, when it comes to modifying the source code for enhancements, the complexity of the code makes it challenging to reiterate through it.

As a program is evolved, its complexity increases unless work is done to maintain or reduce it. — Manny Lehman, Computer Science Researcher

Thousands of lines of code (KLOCs) and messy code structures make it non-understandable, leading to an increase in software maintenance costs. To manage the internal quality of the code, its restructuring is essential. The standard practice for this damage control is called code refactoring.

The code refactoring approach revolves around changing the design and structure of the code so that the software’s external behavior does not get affected. The objective of refactoring is to improve the design of existing code to make it clean and understandable.

Here’s everything you should know about code refactoring.

What is Code Refactoring?

Code refactoring is the process of modifying the code’s internal structure so that its external behavior does not get affected. It helps eliminate the poor design choices (anti-patterns) that make a code challenging to understand and maintain.

Here’s a code refactoring example:

What is the Purpose of Refactoring Code?

Code refactoring is done to:

  • Improve code quality: implies cleaning up code and improving its structure to make it less complex and understandable
  • Maintain a good software architecture: means to enhance the design of the source code to accelerate the delivery of the new product features
  • Minimize cruft: implies minimizing the difference between the current source code and how it should actually be
  • Reduce technical debt: means to reduce messy and unrefined code, which may otherwise lead to additional rework later

As a standard practice, unit tests are written before moving ahead with code refactoring. These unit tests are executed once before the refactoring and once after refactoring. This helps in validating that the external behavior of the software system is not interrupted along the process.

Code Refactoring vs Code Optimization

Though similar to an extent, there is a difference between code refactoring and code optimization. Refer to the table below for a clearer understanding:

Code Refactoring Code Optimization
It helps make the code cleaner so that it is easier to read and understand It helps in faster execution and compilation of the code
Focuses on:

Changing the code structure

Making the code cleaner and understandable

Focuses on:

Reducing memory consumption

Reducing compiling time

What are the Benefits of Code Refactoring?

Creating the first draft of code seems no less than a victory. But, the lengthy code structure can get difficult to decipher when you revisit it in a month or later. This is why refactoring should be a standard practice so that you can run the iterations without feeling lost or confused. Here’s why is code refactoring important in software development:

1. Easy Maintenance

When you have a cleaner and an organized code base, it becomes easy to add new functionalities and fix bugs. The development team can easily read through the code and identify the parts of the code that require modification. The upshot of it — lower maintenance costs.

2. Facilitates Faster Time to Market

Code refactoring accelerates the process of incremental and iterative development by minimizing the impediments on the way. This, in turn, helps in faster shipping and quick upgrades.

3. Reduces Code Rots

Code rot happens when the complexity of the code increases to the extent that it becomes harder to maintain. These code rots are similar to rust layers on the code. With frequent refactoring exercises, you can reduce the code rots to make the code cleaner and understandable.

4. Improves Code Readability

The purpose of refactoring is to transform a computer-understandable code into a human-understandable one. This helps improve readability, which, in turn, makes it easy to make changes even when the development team changes.

5. Promotes Collective Ownership

Collective ownership implies that any individual from the development team can make changes to the code to complete a task or enhance its structure. Code refactoring promotes collective ownership among the Agile development team and allows them to take design decisions that contribute towards maintaining code quality.

6. Reduces Memory Consumption

When all the inconsistencies and duplications from the code are removed, the lines of code get reduced. This, in turn, helps in reducing the memory consumption that an otherwise long source code occupies. Moreover, it also helps in improving the compilation speed.

Popular Code Refactoring Techniques

There are several types of refactoring in software engineering. Some of which include:

1. Composing Method

The objective of this technique is to trim down long and non-understandable methods and eliminate code duplications.

Here is the list of different types of composing methods:

Code Refactoring Technique
Objective
Solution
1. Extract Method Group together an isolated code fragment

Move the code fragment to a new method

Replace the old code with a “call to new method”

2. Inline Method To keep the methods that have an understandable and readable body

Replace the call to the method portion with the method’s content itself

Also, delete the method later

3. Replace Method with Method Object To eliminate a long and complicated method where local variables are unidentifiable

Convert the method into a separate class. This will turn the local variables into the fields of the class

Break down the method into several simply understandable methods within the same class

4. Remove Assignments to Parameters Deal with values assigned to a parameter inside a method

Use a local variable in place of a parameter

2. Moving Features Between Objects

The purpose of moving features among objects is to deal with distributed functionality within different classes. This technique helps in transporting functionality among well-defined classes and in hiding implementation details from the public eye.

Code Refactoring Technique
Objective
Solution
1. Move Method To lower down the method usage in other classes as compared to its own class

Create a new method in the new class that uses that method the most

Move the method code from the old class to the new one

Turn the old method code as a reference to the new method, or you can even remove it completely

2. Remove Middle Man To deal with classes that have many methods

Delete the methods

Force the class to call the end methods directly

3. Extract Class To remove the workload of the class that does the work of two classes

Create a new class

Shift the functionality and related methods to a new class

4. Introduce Foreign Method To deal with a utility class that does not contain the method needed

Add the method to a client class

Add the object of the utility class to the new method as an argument

3. Dealing with Generalization

Generalization helps in abstraction that helps in encapsulation and data hiding. It applies to bulk code.

Here are some of the techniques that help in generalization.

Code Refactoring Technique
Objective
Solution
1. Pull-Up Field To deal with classes that share the same field

Extract the code from a subclass and add it to the superclass to eliminate duplications

2. Pull-Down Field To implement the behavior of a superclass among different superclasses

Extract the code from a superclass and adds it to a subclass

3. Extract Subclass To distribute and generalize the usage of the features of class

Create subclasses and use the feature there

4. Collapse Hierarchy To eliminate the similarity of functionality between a subclass and a superclass

Merge the subclass and the superclass

4. Simplifying Conditional Expressions

Conditional expressions can get complicated over time in context to logic and understandability.

These are some code refactoring techniques that help simplify these conditional expressions:

Code Refactoring Technique
Objective
Solution
1. Decompose Conditional To deal with a complex conditional expression

Decompose the complex conditionals into separate, identifiable methods

2. Remove Control Flag To eliminate a boolean variable that acts as a control flag for different boolean expressions

In place of that variable, consider using – break, continue, or return

3. Introduce Null Object To reduce the frequency of methods that return null

In place of null, let the condition return a null object that showcases default behavior

4. Introduce Assertion Remove expressions that return assumption-driven values

Replace all the assumptions and insert assertion conditions for validating a result

5. Simplifying Method Calls

The objective is to simplify method calls and the interaction between classes.

Some of the code refactoring techniques for simplifying method calls include:

Code Refactoring Technique
Objective
Solution
1. Rename Method To name a method in a way that conveys its intent

Rename methods in a way that it conveys what it does, i.e., it’s objective

2. Hide Method To hide a method that is not used within other classes but only within its own class

Make the method private

3. Replace Exception with Test To avoid using an exception where a simple test would be enough

Impose a condition test in place of an exception

4. Add/Remove Parameter

Add parameter when a method does not have enough data to execute an action

Remove a parameter when it is not used along the method’s body

Add: You need to create a new parameter for passing new information

Remove: You need to eliminate the unused parameter permanently

Code Refactoring in Agile Development: Best Practices

Here are some of the code refactoring best practices:

1. Allocate Hours for Refactoring Every Sprint Cycle

It is always easier to maintain the code quality alongside development. Refactor code on the fly, i.e., refactor small chunks of code along with other sprint activities like fixing bugs and adding new user stories. This reduces the effort the team puts in refactoring large chunks of code.

The product owner should promote refactoring practice from the very beginning and good practice to commit to refactoring is through allocating specific hours for the job.If a team decides to commit 10 hours of the sprint towards refactoring, this gradually becomes standard practice.

2. Mark Comments in the Product Backlog

Developers know when a code smell (a code characteristic that indicates problems with the code) sweeps in the code. So, whenever the development team takes a shortcut or consciously introduces complexity to facilitate fast delivery, they can add notes to that product backlog item and estimate “when will they refactor it.”

This acts as a reminder and helps in returning to the item later on in the product’s lifetime.

3. Run Frequent Tests

Unit testing should be an integral part of code refactoring as it helps validate the proper functioning of the source code. That is why it is essential to run tests — before refactoring, in-between refactoring, and after refactoring.

You can also consider automating tests at this stage for the team’s convenience.

Agile Product Development Report


We respect your privacy. Your information is safe.

4. Leverage Refactoring Tools for Automation

There are many off-the-shelf code refactoring tools available in the market that can help automate the code refactoring process. Some examples of such tools include — Visual Studio Intellicode, Eclipse IDE, Rider, and SonarQube.

Using these code refactoring tools helps run code refactoring alongside development, which further helps in speeding up time to market.

5. Don’t Add Features or Fix Bugs

When the team is actively refactoring the code, try not to mix it with other activities such as adding features or fixing bugs. The sprint should be divided strategically where the team contributes 60% of their time for adding new user stories, 20% of their time to fixing bugs, and the other 20% for code refactoring.

The KPIs of Code Refactoring

How do you know whether you have done a decent job at refactoring? Here are some KPIs to keep track of:

1. Easy to Understand

If you share the code with a fellow developer, they can easily understand what the code does and the other technicalities related to it.

2. The Code Length is Finite

If the code is clear, concise, and manageable — you can consider the code refactoring drill as a success. In simple words, the code should not be a never-ending scrolling activity that is full of duplications.

3. Supports Limited Number of Classes

The more the number of classes, the more are the chances of increased complexities and mess. If the number of classes is limited and manifests understandability, the refactoring practice is heading the right way.

4. It Passes Unit Tests

If the code passes the unit tests before and after refactoring, you can consider code refactoring a success.

Conclusion

Code refactoring is part of software development, where efforts are put to refine, clean, and polish code to make it readable and understandable. The clear objective is to write code that is human-centric over system-centric.

This write-up covers everything about code refactoring, such as its benefits, techniques, best practices, and KPIs. For successful and easy iterative and incremental development in Agile, making code understandable is one essential task. It not only helps reduce technical debt but also helps ensure faster time to market.

The goal of the Agile Development team should be to — Code. Test. Fix Bugs. Refactor. Repeat!

Ready to Make the Best of Your Codebase

Restructure existing code to improve software performance without affecting the current user experience


Manish Garg

About the Author

Manish Garg is a Senior Technical Project Manager at Net Solutions. He handles project deliveries and has an active involvement in the pre-sales functions. He has a rich experience in product development and maintenance. In his free time, he loves reading books. Also, he is a nemophilist looking for new places to explore during vacations.

Leave a Comment

We respect your privacy.

We send one or two emails each month.

We don't do

goodbyes

We do see you later.

Get access to exclusive Insights curated by domain experts to help you Build & Grow your Digital Business

You're all signed up!

We have sent a short welcome email

your way.