Refactoring Practices: Improving Code Readability, Reducing Duplication, and Enhancing Maintainability

Preface – After a year of production experience the author finally read "Refactoring: Improving the Design of Existing Code" and recommends it to engineers who have begun working with real code, emphasizing that the book helped rebuild a habit of reading and thinking about code quality.

Definition of Refactoring – Refactoring is defined as an internal restructuring of software that does not change its observable behavior, aiming to improve understandability and lower modification cost. The author interprets it as making code cleaner and easier for developers to maintain without altering functionality.

Why Refactor

Increase development efficiency: readable code reduces the time spent on understanding existing logic, especially under tight schedules.

Reduce modification risk: eliminating duplicated code and unclear logic lowers the chance of missed or incorrect changes during future updates.

Refactoring Practices

1. Remove Duplicate Code – Duplicated implementations increase maintenance cost. The author shows two similar methods ( public PhotoHomeInitRes photoHomeInit() { … } and public CheckStorageRes checkStorage() { … } ) and suggests extracting common checks into a shared helper.

2. Improve Readability with Effective Comments – Business‑level comments explain *why* a piece of code exists. Example snippet demonstrates adding a comment before a voucher‑processing loop:

List
voucherMarkList = CommonUtil.batchfetchVoucherMark(voucherList);
if (CollectionUtil.isEmpty(voucherMarkList)) {
    return StringUtil.EMPTY_STRING;
}

3. Simplify Complex Conditional Logic – Move intricate predicates into well‑named methods. The article refactors a large if statement into a private method needUpdateRecMaxCount(...) that returns a boolean, making the calling loop easier to read.

4. Reduce Nested If Statements – Use early returns to flatten the control flow. The original nested checks for cardSaveNotifyDTO are rewritten with guard clauses that log and return immediately when a condition fails.

5. Semanticize Fixed Rules – Replace ad‑hoc string concatenations with enumerations that capture the business meaning, e.g., defining enum constants like CARD_POINT_UPDATE with associated scene strings, thus making the rule explicit and searchable.

Thoughts and Summary – Clean code correlates with high quality and maintainability. Refactoring is not an end in itself but a means to keep code tidy, readable, and easy to evolve. Even small, low‑cost improvements are worthwhile when they enhance clarity.

References – The article lists several external reading links (advertising anti‑fraud models, distributed logging, code cleanliness, etc.) and notes that the content is reproduced with permission from the original author.