Concepts
Understanding code and product smells is essential for an Advanced Certified Scrum Developer (A-CSD) and they form a vital part of the Scrums and Agile methodologies. Code smells, product smells, and refactoring strategies play a critical role in maintaining overall software code quality and project delivery.
1. Code and Product Smells
A code smell is any symptomatic instance in the source code of a project that could potentially indicate a deeper problem. It doesn’t necessarily have an immediate impact on the functionality of a program but signifies a program’s weak areas that could expose it to potential risks.
On the other hand, Product smells can be viewed as a set of system-wide issues impacting the overall quality of a product, including factors ranging from user interface glitches to design inefficiencies or structural issues.
Examples of Code and Product Smells
- Long Method: This smell occurs when a method is too long. A method could be considered to be long if it exceeds a certain threshold number of lines of code.
- Data Clumps: Instances where two or more data items constantly appear together are classified as data clumps. For instance, if every time you see an “address”, it is always coupled with a “zip code”, and “city”, it can be defined as a data clump.
- Duplicate Code: This smell comes into the scene when identical or very similar code exists in more than one location in a program.
- Poor User Interface: If the product is not intuitive and easy to navigate for the users, it’s a sign of poor user interface smell.
- Lack of Tests or Documentation: If the product does not come with sufficient testing or documentation features, it is characterized as a product smell.
- Poor Performance: If the product has unresponsiveness, endless loading screens or is slow, it is a prime example of poor performance, demonstrating a product smell.
2. Approaching Code Smells During Refactoring
Refactoring is a disciplined process meant to improve the design of existing code, where its external behavior does not change. The process involves a series of small, behavior-preserving transformations, each of which “clean up” the code, making it easier to understand and change.
Let’s take the Long Method code smell as an example and show how to handle it through refactoring.
Refactoring for a Long Method could involve the following approach:
- Extract Method: The most common refactoring approach that requires you to turn the fragment into a method whose name explains the purpose of the method.
- Replace Temp With Query: You are moving the entire method or a part of it to a separate new method. This new method then replaces the temporary variable.
- Introduce Parameter Object or Preserve Whole Object: These techniques work if you have data items that are always passed together in various parts of the code.
The table below gives a summary:
| Code Smell | Refactoring Strategy |
|---|---|
| Long Method | Extract Method, Replace Temp With Query, Introduce Parameter Object, Preserve Whole Object |
During this refactoring process, it is crucial to involve the entire Scrum team, keeping the increments small and conducting continuous reviews and testing throughout to ensure the code’s functionality isn’t being affected.
In conclusion, identifying code and product smells are vital for maintaining the code’s quality and overall success of the product, which reinforces the need for effective refactoring strategies. For an Advanced Certified Scrum Developer (A-CSD), understanding these aspects and skillfully navigating through them is fundamental.
Answer the Questions in Comment Section
True or False: Code and product smells indicate potential weaknesses in the design or programming of a software product.
- True
- False
Answer: True.
Explanation: Code and product smells are indicators of possible problems within a software product and can suggest areas for refactoring.
Which of the following is an example of a code smell?
- A. Large Class
- B. Duplicate code
- C. Long Parameter List
- D. All of the above
Answer: D. All of the above
Explanation: All these options- large class, duplicate code and long parameter list are examples of code smells that may require refactoring for improving the quality and maintainability of the code.
True or False: Refactoring should only be done when a product is nearing its completion.
- True
- False
Answer: False.
Explanation: Refactoring can be carried out at any stage of the development process, and is often best done incrementally, as and when code and product smells are detected.
In regards to product smells, which of the following might one consider refactoring?
- A. Poor Performance
- B. High Error Rate
- C. Difficulty in use
- D. All of the above
Answer: D. All of the above
Explanation: Product smells can include poor performance, a high error rate, or difficulty in use, which can all be indicators that some aspect of the product may benefit from refactoring.
True or False: Refactoring should aim to add new functionality to the product.
- True
- False
Answer: False.
Explanation: Refactoring is a process of restructuring existing code without changing its external behavior or adding new functionality.
The primary purpose of refactoring is:
- A. To find bugs
- B. To add new features
- C. To improve code readability and reduce complexity
- D. To impress colleagues
Answer: C. To improve code readability and reduce complexity
Explanation: Refactoring improves the design of existing code, makes it more readable, reduces complexity, and should aid understanding.
The term ‘Long Method’ refers to which of the following?
- A. A method that has too many lines of code
- B. A method that takes a long time to execute
- C. A method that has a long name
- D. None of the above
Answer: A. A method that has too many lines of code
Explanation: ‘Long Method’ is a code smell that implies a method is trying to do too much and may need to be split up to improve clarity.
True or False: Refactoring is a one-time process.
- True
- False
Answer: False.
Explanation: Refactoring is an ongoing process that evolves with the codebase. As new code smells are detected or as parts of the codebase become more complex, further refactoring may be needed.
Which of the following statements about ‘Duplicate Code’ is true?
- A. Duplicate code is a preferred practice in coding
- B. Duplication helps in increasing codebase volume
- C. Duplicate code is a code smell that hints refactoring may be needed
- D. All of the above
Answer: C. Duplicate code is a code smell that hints refactoring may be needed
Explanation: Duplication can lead to code that is harder to maintain and more prone to bugs. It’s a code smell suggesting that some part of the code could be abstracted and reused.
True or False: Product smells can only be caught through automated testing.
- True
- False
Answer: False.
Explanation: While automated testing can catch some product smells, others may only become apparent through manual testing or user feedback.
Which of the following could be an effective way to approach refactoring of ‘Long Method’ code smell?
- A. Increase method length
- B. Ignore the issue
- C. Divide the method into smaller, more manageable methods
- D. Duplicate the method elsewhere
Answer: C. Divide the method into smaller, more manageable methods
Explanation: Breaking down a long method into smaller methods makes the code more readable and maintainable.
The ‘Inappropriate Intimacy’ code smell refers to:
- A. Two very long methods
- B. A method that is too complex
- C. Two classes that depend heavily on each other’s implementation
- D. Multiple classes with the same functionality
Answer: C. Two classes that depend heavily on each other’s implementation
Explanation: Inappropriate Intimacy is a code smell where two classes are overly coupled or depend too much on each other’s implementation, which is a sign for need of refactoring.
Thanks for sharing this blog post! Can you briefly explain what code smells are?
Code smells are indicators of potential problems in your codebase that might make it difficult to maintain or extend. Examples include duplicated code, long methods, and large classes.
Can someone explain what product smells are? I haven’t come across this term before.
One common code smell is duplicated code. It’s usually better to refactor it into a reusable method or class.
Another code smell is long methods. Functions that are too long can be hard to understand and test.
Large classes are a code smell as well. A class that does too many things should be broken down into smaller, more focused classes.
To refactor long methods, you can break them down into smaller, more manageable functions. This makes the code easier to read and test.
Thanks, this blog post was really helpful!