Refactoring Legacy Code like a Pro: a Use Case. from Udemy

Master The Art of Refactoring Messy Codebases Into a Software Masterpiece and Become the go-to expert for codebase transformations by learning to take messy code as an opportunity to innovate and grow.

But what is legacy code in the first place?

Legacy code refers to software code or applications that were created in the past and have been in use for a significant period. However, such code often poses challenges because it may be outdated, poorly documented, or not aligned with current coding standards and best practices. These challenges can make it difficult to maintain, update, or extend the software, thereby causing potential problems for developers to refactor to make it easy for future work.

In his Amazing book Working Effectively With Legacy Code, According to Michael Feathers, Legacy Code refers to any code that lacks automated tests: To me, legacy code is simply code without tests.

In this course, we will explore practical ways of dealing with legacy codebases. Our approach covers everything from automated tests to detailed techniques for making codebases flexible and enjoyable to work with.

By the end of the course...

You'll spot refactoring signals.
You'll be able to cover legacy code with tests.
You'll master refactoring principles and best practices.
You'll master techniques to improve the test coverage.
You'll identify common code smells and anti-patterns.
You'll confidently tackle complex legacy codebases.

Before You BUY This Course

If you're new to the world of code refactoring and looking for an affordable starting point, we recommend diving into specific books on the subject. Books (less than 60$) such as Refactoring or Working Effectively with Legacy Code provide a cost-effective way to build a strong foundation in refactoring principles, allowing you to learn at your own pace.

Once you're ready to put your knowledge into action on real legacy code, our comprehensive course guides you through practical application and advanced techniques, ensuring you're fully equipped to tackle complex code bases confidently.

What's the Use case?

In this course, we will refactor a codebase that calculates prayer times provided by Prayer Times Organization. We will address the challenges posed by outdated technologies, inadequate code organization, and the need to improve code readability.

With clear objectives in mind, we'll break down the refactoring process into manageable steps, including:

Code analysis.
Test setup.
Modularization.
Extracting meaningful abstraction.
Reducing the clutter.
Emphasizing best practices.
And much more.

The use case presents a good enough complex code to showcase the difficulties you can face when refactoring a real project. By the end of the course, you'll be well-prepared to take on real-world refactoring projects with confidence and expertise.

You can check the preview up in a video for a full explanation of the domain problem, so if that excites you, join now, and let us refactor a messy codebase.

Language Agnostic

This course is designed to be language-agnostic, meaning you can acquire essential principles and techniques that apply universally across various codebases in different programming languages.

While our use cases in the course choose Kotlin, you can still find on the domain problem website other versions that apply to Java, Python, C#, C++, and PHP; the skills and insights you gain are easily transferable to any other language.

We emphasize Kotlin to provide a practical learning experience, but the knowledge you acquire will empower you to excel in legacy code refactoring, regardless of your chosen programming language.

What's inside

Learning objectives

Learn how to spot refactoring signals.
Learn techniques to improve the test coverage.

Master refactoring principles and best practices.
You'll confidently tackle complex legacy codebases.

Learn how to spot refactoring signals.
Learn techniques to improve the test coverage.
Master refactoring principles and best practices.
You'll confidently tackle complex legacy codebases.

Syllabus

Introduction

Course Introduction

Domain Problem

Extra Resources

Traffic lights

Read about what's good

what should give you pause

and possible dealbreakers

Emphasizes test coverage, which is crucial for maintaining and evolving legacy systems and ensuring code reliability during refactoring

Teaches refactoring principles applicable across different programming languages, making it valuable for developers working in diverse environments

Recommends books as a starting point, suggesting that learners without prior refactoring knowledge may benefit from foundational study first

Uses Kotlin in its use case, but the principles are transferable to Java, Python, C#, C++, and PHP, broadening its applicability

Explores mutation testing, which is an advanced technique for evaluating the effectiveness of test suites and improving code quality

Requires learners to have access to books, which may pose a barrier to entry for some learners who do not have these resources

Reviews summary

Refactoring legacy code: practical, test-driven approach

According to learners, this course offers a practical and actionable approach to dealing with challenging legacy codebases. Students particularly praise the strong emphasis on testing, highlighting how learning to add tests to untested code provides a crucial safety net before attempting complex refactors. The use case application is seen as invaluable for demonstrating concepts, and the principles taught are highly transferable across different programming languages, despite the use of Kotlin in examples. While some found the pace occasionally slow or the single use case perhaps too simple for highly complex real-world scenarios, the course is widely regarded as providing a solid foundation and increasing confidence in tackling legacy code.

Concepts apply across programming languages.

"The Kotlin use case... principles are language-agnostic."

"The skills and insights you gain are easily transferable to any other language."

"The core concepts apply universally."

Demonstrates concepts with a specific example.

"The practical application via the use case is invaluable."

"The use case is a good way to follow along."

"The use case felt a bit too simple compared to the real legacy code I deal with at work."

Crucial module on testing legacy code.

"Learning how to use testing as a safety net before making changes was a game-changer."

"The testing module alone is worth the price of admission."

"The emphasis on testing is crucial and well-taught."

Offers actionable methods for real code.

"This course is fantastic! It demystifies legacy code and provides practical, actionable techniques."

"Absolutely brilliant. The approach to tackling large, messy codebases is exactly what I needed."

"I learned how to use practical tools and strategies that I could apply immediately to my work."

Some found pace slow or wanted more.

"Some parts felt a bit slow..."

"I wish there was more focus on refactoring strategies specific to different languages or code structures beyond the single use case."

"Would have loved to see more diverse examples or case studies."

Activities

Be better prepared before your course. Deepen your understanding during and after it. Supplement your coursework and achieve mastery of the topics covered in Refactoring Legacy Code like a Pro: a Use Case. with these activities:

Read 'Working Effectively with Legacy Code'

Show steps

Solidify your understanding of legacy code challenges and solutions. This book provides a comprehensive guide to the principles and practices covered in the course.

View Brutal Refactoring on Amazon

Show steps

Obtain a copy of 'Working Effectively with Legacy Code'.
Read the book, focusing on chapters related to testing and refactoring techniques.
Take notes on key concepts and strategies.
Relate the book's content to the course's use case and examples.

Practice Writing Unit Tests

Show steps

Sharpen your unit testing skills before diving into legacy code. Writing effective tests is crucial for safely refactoring and improving code quality.

Browse courses on Unit Testing

Show steps

Choose a language and testing framework (e.g., JUnit for Java, pytest for Python, or KotlinTest for Kotlin).
Write unit tests for simple functions or classes.
Practice writing different types of tests (e.g., boundary tests, error handling tests).
Review testing best practices and principles.

Create a Test Suite for an Open-Source Project

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Apply your testing and refactoring skills to a real-world project. This will give you hands-on experience with legacy code and the challenges it presents.

Show steps

Find an open-source project with limited test coverage.
Analyze the codebase and identify areas that need testing.
Write unit tests to improve the project's test coverage.
Submit your tests as a pull request to the project.

Four other activities

Expand to see all activities and additional details

Show all seven activities

Refactor Code Smells

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Hone your ability to identify and refactor common code smells. This will improve your code quality and make it easier to maintain.

Show steps

Find code examples with common code smells (e.g., long methods, duplicated code, large classes).
Refactor the code to remove the code smells.
Compare the original code with the refactored code.
Ensure that the refactored code is more readable and maintainable.

Document Refactoring Steps

Show steps

Reinforce your understanding by documenting the refactoring process. This will help you internalize the steps and principles involved.

Show steps

Choose a refactoring technique covered in the course.
Find a code example that can be refactored using that technique.
Document the steps involved in refactoring the code.
Explain the benefits of the refactoring.

Read 'Refactoring: Improving the Design of Existing Code'

Show steps

Deepen your knowledge of refactoring techniques and patterns. This book provides a comprehensive catalog of refactorings with detailed explanations and examples.

View Melania on Amazon

Show steps

Obtain a copy of 'Refactoring: Improving the Design of Existing Code'.
Read the book, focusing on the refactorings that are most relevant to your work.
Practice applying the refactorings to your own code.
Compare your results with the examples in the book.

Help Others Refactor

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Solidify your understanding by helping others with their refactoring challenges. Teaching is a great way to learn.

Show steps

Offer to help colleagues or friends with their refactoring projects.
Provide guidance and support as they work through the refactoring process.
Share your knowledge and experience with them.
Answer their questions and address their concerns.

Career center

Learners who complete Refactoring Legacy Code like a Pro: a Use Case. will develop knowledge and skills that may be useful to these careers:

Software Maintenance Engineer

A software maintenance engineer specializes in updating and fixing existing software applications. If you are a software maintenance engineer, applying the techniques taught in this course will allow you to tackle messy codebases. You'll master refactoring principles and be able to improve the test coverage. You'll also learn how to spot refactoring signals and learn best practices. By the end of the course, you'll be able to confidently tackle complex legacy codebases.

See salaries and explore the career path for Software Maintenance Engineer

Software Engineer

A software engineer designs, develops, and maintains software systems. This course provides an excellent opportunity for software engineers to enhance their skills in refactoring legacy codebases. By mastering refactoring principles, best practices, and techniques to improve test coverage, a software engineer can significantly improve the maintainability, readability, and flexibility of code they encounter, making them more effective in their role. The course's language-agnostic approach is well-suited for a software engineer who has to work with code written in multiple languages. The techniques for identifying code smells, anti-patterns, and refactoring signals, taught in this course, help a software engineer tackle complex legacy codebases confidently.

See salaries and explore the career path for Software Engineer

Software Developer

A software developer is involved in the coding, testing, and debugging of software. This course directly impacts a software developer's ability to handle legacy codebases effectively. The course emphasizes refactoring principles, best practices, and techniques to improve test coverage, directly helping improve code quality and maintainability. A software developer can use the course's focus on identifying code smells and anti-patterns to write cleaner code from the start. The course will empower the software developer to confidently tackle complex legacy codebases.

See salaries and explore the career path for Software Developer

Full-Stack Developer

A full stack developer works on both the frontend and backend aspects of a software application. For a full stack developer, this course provides techniques to tackle messy codebases. They'll master refactoring principles, best practices, and techniques to improve test coverage, directly impacting code quality and maintainability. The full stack developer will benefit from spotting refactoring signals and confidently tackling complex legacy codebases. The course's hands-on approach is beneficial for a full stack developer involved in diverse projects.

See salaries and explore the career path for Full-Stack Developer

Code Reviewer

A code reviewer examines code changes for quality, style, and adherence to standards. This course provides a code reviewer with the tools to identify code smells, anti-patterns, and areas needing refactoring. By mastering the techniques from the course, the code reviewer can provide more constructive feedback to developers, ensuring codebases remain maintainable and aligned with best practices. The course's emphasis on test coverage and modularization is also valuable for ensuring that changes do not introduce regressions or increase technical debt. A code reviewer can use insights from the course, especially on identifying refactoring signals, to improve the overall code quality.

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Technical Lead

A technical lead guides a team of developers, providing technical direction and ensuring code quality standards are met. A technical lead can leverage the skills from this course to spot refactoring signals and guide their team in improving existing codebases. The course's emphasis on refactoring principles, best practices, and techniques to improve test coverage enables the technical lead in improving the quality, readability, and maintainability of the code. By mastering these techniques from the course, the technical lead can lead their team in modernizing legacy systems and ensure a more robust and reliable software product.

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Application Developer

An application developer designs and builds software applications. This course may equip you with the skills to tackle messy codebases effectively. You'll master refactoring principles and learn techniques to improve test coverage. The course's focus on identifying common code smells and anti-patterns may also help you to write cleaner and more maintainable code from the outset. You'll also learn to spot refactoring signals and apply the best practices. By the end of the course, you'll be able to confidently tackle complex legacy codebases.

See salaries and explore the career path for Application Developer

Software Architect

A software architect is responsible for making high-level design choices and setting technical standards, including coding standards, for software development. This course helps a software architect understand how to guide teams in refactoring legacy systems. It teaches principles and practices that are vital for ensuring codebases remain maintainable and adaptable. The software architect will benefit from the course's focus on test coverage, modularization, and extracting meaningful abstractions, as these are vital for creating robust and scalable systems. By mastering these techniques, a software architect can lead teams more effectively in modernizing and improving existing codebases.

See salaries and explore the career path for Software Architect

Backend Developer

A backend developer specializes in server-side logic and databases. This course may provide critical skills for a backend developer working with existing systems. You may become more aware of refactoring principles, best practices, and techniques to improve test coverage. The ability to identify code smells and anti-patterns could improve the quality and maintainability of backend code. The course's focus on modularization and extracting meaningful abstractions may help the backend developer to manage databases more efficiently.

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Software Consultant

A software consultant advises organizations on technical strategies and solutions, often involving legacy system modernization. This course provides a software consultant with the knowledge and expertise to assess and recommend improvements to existing codebases. By mastering refactoring principles, best practices, and techniques to improve test coverage, a software consultant can provide actionable recommendations to clients. The course's emphasis on modularization and extracting meaningful abstractions is also valuable for architecting more maintainable and scalable systems. This course will help the consultant with confidently tackling complex legacy codebases.

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DevOps Engineer

A DevOps engineer automates and streamlines the software development lifecycle, often dealing with legacy systems. This course provides a DevOps engineer with the skills to better manage and improve the codebases they work with. The course's emphasis on test coverage and refactoring principles enables the DevOps engineer to create more robust and reliable deployment pipelines. By understanding how to tackle complex legacy codebases, a DevOps engineer can reduce the risk of introducing errors during deployments and improve the overall stability of the system. The course helps a DevOps engineer to master techniques for improving test coverage.

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QA Engineer

A quality assurance engineer ensures software meets required standards by designing and executing tests. This course may help a quality assurance engineer understand how to write effective tests for legacy code, improving overall test coverage. By mastering techniques to improve test coverage and identifying common code smells and anti-patterns, a quality assurance engineer can better identify and prevent defects. The course's emphasis on refactoring principles and best practices may also provide a QA Engineer a better understanding of how code changes can impact the overall system.

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System Analyst

A system analyst researches problems and plans solutions for software systems. This course may help a systems analyst understand the challenges of working with legacy code. This course may help a system analyst learn principles, best practices, and techniques to improve test coverage. You'll also learn about modularization and extracting meaningful abstractions. The course's emphasis on identifying common code smells and anti-patterns may help system analyst in recommending more robust and maintainable systems.

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Data Scientist

A data scientist analyzes data, develops statistical models, and implements machine learning algorithms. A data scientist typically requires advanced degrees, such as a master's or a doctorate. While this course may not be directly related to data science, a data scientist may find this course useful to maintain existing codebases. This course may help you to learn techniques to improve the test coverage. The course's emphasis on refactoring principles and best practices may help you to manage data infrastructure more effectively. After this course, you will be prepared to tackle complex legacy codebases.

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Data Engineer

A data engineer designs, builds, and maintains data processing systems and infrastructure. While this course may not be directly related to data engineering, the skills from this course may be useful in maintaining data pipelines and ETL processes. This course may help you to learn techniques to improve the test coverage. The course's emphasis on refactoring principles and best practices may help you to manage data infrastructure more effectively. After this course, you will be prepared to tackle complex legacy codebases.

See salaries and explore the career path for Data Engineer

Refactoring Legacy Code like a Pro

a Use Case.

What's inside

Learning objectives

Syllabus

Traffic lights

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Reviews summary

Refactoring legacy code: practical, test-driven approach

Activities

Career center

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