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Use Case - Refactoring Trigger

publish date: 2026/06/24 21:38:16.991051 UTC

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While adding a new feature, a developer notices the same dozen lines of validation logic copy-pasted in five different files across the codebase. Following standard refactoring guidance, what would be the most appropriate action?

Delete the validation logic entirely from all five files without replacement

Copy the same logic into a sixth file to keep the pattern consistent

Leave all five copies unchanged to avoid touching any existing working code

Extract the duplicated logic into a single shared method and have all five locations call it

Correct Answer

Extract the duplicated logic into a single shared method and have all five locations call it

Explanation

This is the classic 'duplicate code' bad smell. The recommended refactoring response is to apply an extract method transformation, consolidating the duplicated logic into a single reusable method and having all the original locations call it. This reduces future maintenance burden, since a fix or update only needs to be made in one place.

Reference

Software Engineering, Ian Sommerville, 10th edition

Quizzes you can take where this question appears

Software Evolution - Use Case Scenarios