Code smells and product smells are common problems that can occur in any software development process, regardless of its methodology. They are often indicators of poor design and coding practices, which can make your software harder to understand and maintain. By identifying and resolving these smells, developers can significantly improve the overall quality of their software.
Types of Code and Product Smells
Let’s begin by discussing three types of code and product smells:
-
Long Method:
This is a code smell that occurs when a method has too many lines of code. It is considered a smell because it makes the method difficult to understand and to maintain. Additionally, long methods are often harder to test since they have a high degree of complexity and are prone to bugs.
-
Duplicate Code:
If you see the same block of code in more than two places, then you likely have duplicate code. This is a sign that abstraction is needed. Not addressing this smell can make your system more difficult to maintain and update, because changes have to be done in multiple places.
-
God Class:
This is a code smell where one class knows too much or does too much. A God Class often means that your program is not sufficiently modular, which makes it more difficult to maintain and modify.
Addressing the Long Method Smell
Let’s now focus on the Long Method smell and outline how you can approach it:
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Code Review:
The first step in refactoring long methods is to identify them. Review the code to find methods that seem to be too long or complex.
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Extract Method:
The next step is to break the long method into smaller methods. If a method is doing multiple things, each individual task should be a separate method.
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Test:
After breaking down the method, it’s essential to conduct tests. This ensures that the new methods are functioning as expected.
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Re-evaluate:
When breaking down the method, it may still be long or complex. If so, you’ll need to re-evaluate your changes and maybe break it down even further.
Sample Code Evaluation
As an example, let’s take the following code:
java
public void calculateScore() {
// Calculate the score based on various factors
int factor1 = 5;
int factor2 = 10;
int factor3 = 15;
int score = factor1 + factor2 + factor3;
// Apply bonus if applicable
boolean isBonusApplicable = checkBonusApplicable();
if (isBonusApplicable) {
score = applyBonus(score);
}
// Store the score
storeScore(score);
}
This method does three different actions (calculating the score, applying a bonus, storing the score) which makes it long.
By extracting methods, we can improve it as follows:
java
public void calculateScore() {
int score = computeScore();
score = applyBonusIfApplicable(score);
storeScore(score);
}
private int computeScore() {
int factor1 = 5;
int factor2 = 10;
int factor3 = 15;
return factor1 + factor2 + factor3;
}
private int applyBonusIfApplicable(int score) {
boolean isBonusApplicable = checkBonusApplicable();
if (isBonusApplicable) {
score = applyBonus(score);
}
return score;
}
In the refactored code, each method does only one thing, which results in single-purpose, shorter and cleaner methods.
Conclusion
To summarize, code smells and product smells can have damaging effects on the quality of software. As such, they are something to be taken into consideration for any Certified Scrum Developer. By identifying and resolving them early in the development cycle, developers can ensure that software delivered by each sprint is of the highest quality.
Practice Test
True/False: Code smell is a non-technical sign that indicates a deeper problem in the system.
- True
- False
Answer: True
Explanation: Code smells are indications that something might be wrong at a deeper level. They are not bugs, but rather poor design and implementation choices.
True/False: Every code smell should be eliminated at all costs.
- True
- False
Answer: False
Explanation: While having code with fewer smells is generally better, eliminating all code smells might not always be the best approach. Some might not affect the overall operation, and fixing them might lead to unnecessary complexity.
A typical example of a code smell is:
- A) Examples without assertions
- B) Overcomplicated function
- C) Excessive use of global variables
- D) All of the above
Answer: D) All of the above
Explanation: These are all types of code smells. Overcomplicated functions and excessive use of global variables indicate poor software design, while tests without assertions can lead to miss detection of bugs.
What does refactoring refer to in software development?
- A) Breaking down a piece of software to build it again
- B) Copying the source code of another project
- C) The process of modifying the system to improve design
- D) Fixing the identified bugs in the program
Answer: C) The process of modifying the system to improve design
Explanation: Refactoring is a disciplined technique to restructuring an existing body of code by altering its internal structure without changing its external behaviour.
True/False: Product smell is a characteristic of a product that indicates a potential problem in the product itself, outside of the code.
- True
- False
Answer: True
Explanation: Similar to ‘code smell’, ‘product smell’ indicate potential issues not necessarily tied to code, like usability, feature bloat, or documentation.
Duplicated code is an example of:
- A) Code smell
- B) Product smell
- C) Both
- D) Neither
Answer: A) Code smell
Explanation: Duplicated code is a code smell, implying that there might be a deeper design issue at hand. It affects maintainability and can propagate bugs.
Refactoring:
- A) Always improves performance
- B) Aims to improve code readability and reduce complexity
- C) Introduces new functionality
- D) Alters the external behavior of the software
Answer: B) Aims to improve code readability and reduce complexity
Explanation: Refactoring does not introduce new functionality or necessarily improve performance, its purpose is to enhance the design and maintainability of the code.
What is a ‘large class’ code smell?
- A) A class with many instance variables
- B) A class with minimal instance variables
- C) A class with fewer method definitions
- D) A class that encapsulates many functionalities
Answer: A) A class with many instance variables
Explanation: A ‘large class’ code smell suggests that a class is trying to do too much and could potentially be broken down into smaller more focused classes.
Indecisive classes is an example of:
- A) Code smell
- B) Product smell
- C) Both A and B
- D) Neither A nor B
Answer: A) Code smell
Explanation: Indecisive classes is a code smell that indicates the class has too many responsibilities and might not adhere to the Single Responsibility Principle.
A convoluted design is an example of:
- A) A code smell
- B) A product smell
- C) Both A and B
- D) Neither A nor B
Answer: B) A product smell
Explanation: A convoluted design typically indicates a usability or user experience problem, rather than a code-specific issue, making it a ‘product smell’.
Interview Questions
Question 1: What are code smells?
Answer 1: Code smells are specific characteristics in the code that may indicate a deeper problem with the code’s structure or design.
Question 2: What is the God Class smell?
Answer 2: The God Class smell refers to a class that has too many responsibilities or functions, violating the Single Responsibility Principle.
Question 3: What is the Long Method smell?
Answer 3: The Long Method smell refers to a method that is excessively long, making it harder to understand and maintain.
Question 4: What is the Duplicated Code smell?
Answer 4: The Duplicated Code smell occurs when the same or similar code is repeated in multiple places within a codebase, leading to potential maintenance issues.
Question 5: How can you approach refactoring a God Class?
Answer 5: To refactor a God Class, one approach is to identify cohesive groups of methods and fields within the class that can be extracted into separate classes.
Question 6: What are some strategies to address the Long Method smell during refactoring?
Answer 6: Strategies to address the Long Method smell include breaking down the method into smaller, more manageable chunks, extracting repeated code into separate methods, and improving code readability by using meaningful names.
Question 7: How can you refactor code to eliminate the Duplicated Code smell?
Answer 7: To eliminate the Duplicated Code smell, you can create a reusable function or method to replace the duplicated code segments, ensuring that changes need only be made in one place.
Question 8: Why is it important to address code and product smells during the development process?
Answer 8: Addressing code and product smells early in the development process can lead to better-quality software, improved maintainability, and reduced technical debt.
Question 9: Can code and product smells impact the effectiveness of Agile and Scrum practices?
Answer 9: Yes, code and product smells can hinder the effectiveness of Agile and Scrum practices by making it more challenging to adapt to changing requirements and slowing down development cycles.
Question 10: How can the continuous integration and continuous deployment practices help in identifying and addressing code and product smells?
Answer 10: By integrating automated testing, static code analysis tools, and code review processes into the CI/CD pipeline, teams can quickly identify and address code and product smells as part of the development workflow.
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