Benefits of Removing Code Duplication

Oct 13, 2025 by wbrum.org 133 views

Introduction

In software development, code duplication is a common issue that can lead to maintenance problems and make it difficult to modify the codebase. When working on the PADL project, we encountered a situation where two classes, PackageDefault and PackageGhost, shared the same methods with identical implementations. In this article, we will explore ways to remove this code duplication and improve the overall quality of the codebase.

The Issue

While using the GLASS tool on the PADL project, we noticed that both PackageDefault and PackageGhost classes have the following methods with the same implementation:

void addConstituent(IGhost aGhost)
void addConstituent(IPackageGhost aPackageGhost)

These methods are used to add constituents to the package, but they have the same logic and implementation. This code duplication can make it difficult to maintain the codebase and can lead to errors if changes are made to one of the methods without updating the other.

Possible Solutions

There are several possible solutions to remove this code duplication:

1. Make One Class a Subclass of the Other

One possible solution is to make one of the classes a subclass of the other. This would allow us to inherit the methods and avoid code duplication. However, this approach may not be suitable in this case, as it could affect the type hierarchy and make it difficult to understand the relationships between the classes.

2. Use a Pull-Up Refactoring

Another possible solution is to use a pull-up refactoring and add the methods to the Package class. This would allow us to remove the code duplication and make the code more maintainable. However, this approach may not be suitable if the methods are specific to the PackageDefault and PackageGhost classes.

3. Remove the Methods Completely

A third possible solution is to remove the methods completely. If the methods are not essential to the functionality of the classes, we can simply remove them and avoid code duplication. However, this approach requires careful consideration and may not be suitable in all cases.

Benefits of Removing Code Duplication

Removing code duplication has several benefits, including:

Improved maintainability: By removing code duplication, we can make the code more maintainable and easier to understand.
Reduced errors: Code duplication can lead to errors if changes are made to one of the methods without updating the other. By removing code duplication, we can reduce the risk of errors.
Increased productivity: By removing code duplication, we can increase productivity and make it easier to develop new features.

Conclusion

In conclusion, code duplication is a common issue that can lead to maintenance problems and make it difficult to modify the codebase. By exploring possible solutions, such as making one class a subclass of the other, using a pull-up refactoring, or removing the methods completely, we can remove code duplication and improve the overall quality of the codebase. By removing code duplication, we can improve maintainability, reduce errors, and increase productivity.

Recommendations

Based on our analysis, we recommend the following:

Use a pull-up refactoring: We recommend using a pull-up refactoring and adding the methods to the Package class. This would allow us to remove the code duplication and make the code more maintainable.
Remove the methods completely: If the methods are not essential to the functionality of the classes, we recommend removing them completely. This would allow us to avoid code duplication and make the code more maintainable.

Future Work

In the future, we plan to:

Continuously monitor the codebase: We will continuously monitor the codebase for code duplication and take steps to remove it.
Improve the code quality: We will improve the code quality by following best practices and using tools to detect code duplication.
Develop new features: We will develop new features and improve the overall functionality of the codebase.

References

[1] GLASS tool documentation
[2] PADL project documentation
[3] Code duplication removal techniques

Appendix

The following is an example of how to use a pull-up refactoring to remove code duplication:

public class Package {
    // ...

    public void addConstituent(IGhost aGhost) {
        // implementation
    }

    public void addConstituent(IPackageGhost aPackageGhost) {
        // implementation
    }
}

Introduction

In our previous article, we explored ways to remove code duplication between PackageDefault and PackageGhost classes. In this article, we will answer some frequently asked questions (FAQs) related to code duplication and refactoring.

Q&A

Q: What is code duplication?

A: Code duplication is a situation where the same code is repeated in multiple places in a program. This can lead to maintenance problems and make it difficult to modify the codebase.

Q: Why is code duplication a problem?

A: Code duplication is a problem because it can lead to:

Maintenance issues: If changes are made to one instance of the duplicated code, it may not be reflected in the other instances.
Error-prone code: Duplicated code can lead to errors if changes are made to one instance without updating the other.
Increased complexity: Code duplication can make the codebase more complex and difficult to understand.

Q: How can I identify code duplication?

A: You can identify code duplication by:

Using code analysis tools: Tools like SonarQube, CodeCoverage, and CodeDuplication can help you identify duplicated code.
Reviewing code manually: Reviewing code manually can help you identify duplicated code, but it can be time-consuming and error-prone.

Q: What are some common causes of code duplication?

A: Some common causes of code duplication include:

Copy-paste programming: Copying and pasting code from one place to another without modifying it.
Lack of abstraction: Failing to abstract common code into reusable functions or classes.
Inadequate testing: Failing to test code thoroughly, leading to duplicated code.

Q: How can I refactor duplicated code?

A: You can refactor duplicated code by:

Extracting common code: Extracting common code into reusable functions or classes.
Using inheritance: Using inheritance to inherit common code from a parent class.
Using composition: Using composition to compose objects from reusable components.

Q: What are some best practices for avoiding code duplication?

A: Some best practices for avoiding code duplication include:

Writing modular code: Writing code that is modular and reusable.
Using abstraction: Using abstraction to hide common code and make it reusable.
Testing code thoroughly: Testing code thoroughly to ensure it is correct and efficient.

Q: How can I measure the effectiveness of code duplication removal?

A: You can measure the effectiveness of code duplication removal by:

Using metrics: Using metrics such as code coverage, code duplication, and code complexity to measure the effectiveness of code duplication removal.
Reviewing code: Reviewing code manually to ensure that duplicated code has been removed.
Testing code: Testing code thoroughly to ensure that it is correct and efficient.

Conclusion

In conclusion, code duplication is a common problem that can lead to maintenance issues, error-prone code, and increased complexity. By identifying and refactoring duplicated code, we can improve the quality and maintainability of our codebase. By following best practices and using tools to detect code duplication, we can avoid code duplication and make our code more efficient and maintainable.

Recommendations

Based on our analysis, we recommend the following:

Use code analysis tools: Use tools like SonarQube, CodeCoverage, and CodeDuplication to identify duplicated code.
Refactor duplicated code: Refactor duplicated code by extracting common code, using inheritance, and using composition.
Follow best practices: Follow best practices such as writing modular code, using abstraction, and testing code thoroughly.

Future Work

In the future, we plan to:

Continuously monitor the codebase: Continuously monitor the codebase for code duplication and take steps to remove it.
Improve the code quality: Improve the code quality by following best practices and using tools to detect code duplication.
Develop new features: Develop new features and improve the overall functionality of the codebase.

References

[1] GLASS tool documentation
[2] PADL project documentation
[3] Code duplication removal techniques

Appendix

The following is an example of how to use a pull-up refactoring to remove code duplication:

public class Package {
    // ...

    public void addConstituent(IGhost aGhost) {
        // implementation
    }

    public void addConstituent(IPackageGhost aPackageGhost) {
        // implementation
    }
}

In this example, we have removed the code duplication by adding the methods to the Package class. This allows us to avoid code duplication and make the code more maintainable.