Code refactoring: Do’s and don’ts
Code refactoring is great, because who doesn’t like optimized code? Unfortunately, sometimes it leads to hard-to-find errors. So, what’s a dev to do? In this article, Lolita Rogers goes over the do’s and don’ts of code refactoring and share some techniques to save yourself trouble down the line.
Code Refactoring is a process of application’s restructuring which optimizes its internal structure, but leaves its basic functionality untouched. Being a component of framework development, refactoring can cause difficult-to-detect bugs due to incorrect utilization. It is important to adhere to 4 basic rules to narrow down the chances of errors’ occurrence.
- Systemization. In most cases, refactoring is used as an auxiliary tool during the scaling and modification of software, so before starting practicing various refactoring techniques, one should first make a refactoring of the software’s previous version, add new features and only then make a refactoring of updated version’s code.
- Prepared tool set. One must plan a certain set of self-checking tests that will detect errors before the code refactoring. This stage can take plenty of time and requires the skills in testing of both manual and automated software.
- Deliberation and stepping. The code must be debugged after each alteration in code block dedicated to a certain function is made and then the code refactoring can be initiated.
- Accessibility. Correctly executed refactoring makes the code more readable and flexible for the further scaling and restructuring of a certain software.
When do we need code refactoring?
Not all the IT companies need to utilize code refactoring techniques in every project due to the increasing terms of project’s implementation and risk of the occurrence of errors that can only be detected by later testing with the help of white-box technique.
The refactoring is irreplaceable, however, if:
- One needs to make the code more readable and less capacious;
- Similar code blocks are frequently repeated in one’s application;
- One needs to expand the opportunities of existing application;
- There are big blocks featuring conditional operators used in one’s application.
Code refactoring techniques
As of today, IT companies work with quite extensive list of code refactoring techniques. Applied techniques for a code refactoring can, in particular, help increase the abstractness of code, separate it into a few logic parts, correctly rename the variables, classes and functions and implement the optimal code blocks rearrangement.
The most frequently used refactoring technique examples are presented below:
- Encapsulate Field: as the direct access to fields inside a certain class could cause problems, it is strongly recommended to apply getters and setters;
- Extract Class: this and next three techniques are based on the single responsibility method, which contributes to the increased tolerance of changes; make sure your classes adhere to atomicity and, if necessary, extract some functionality into the new one;
- Extract Interface: if different clients use the same class interface part, it is recommended to separate this part into a stand-alone interface;
- Extract Local Variable: this technique is used to simplify the understandability and, as a result, traceability of local expressions;
- Extract Method: break up long methods into self-standing smaller parts;
- Generalize Type: make your classes more general, for example, by moving a child method into a parent class or implementing an interface;
- Inline: a group of techniques opposite to the extraction, based on combining simple pieces of code into one method, unless they used in multiple places; it shortens code removing unnecessary identifiers;
- Introduce Factory: create a factory method to replace default constructors when creating an object;
- Introduce Parameter: in order not to mix parameters, convert them into named ones;
- Pull Up: eliminate code duplication by pulling code parts into a superclass;
- Push Down: the opposite of the previous technique; if the behavior implemented in a superclass is used in few subclasses, move it into these subclasses;
- Replace Conditionals with Polymorphism: get rid of insufficient identical conditionals.
The refactoring procedure can appear difficult due to problematic working-out of self-checking tests and inability of deviation from pre-existing application’s functionality. As a cause, the refactoring process is only trusted to highly skilled experts who are able to fully grasp the basic idea of the prewritten code and possess the advanced skills in its optimization.
When the refactoring is unnecessary?
There is a number of situations where the utilization of refactoring is unnecessary. For example, when the application has to be rewritten due to its totally unreadable code, irrational usage of resources or mere inoperability (when the effort dedicated to correction of errors and further refactoring outweighs the effort dedicated to the application’s full redevelopment). One has to be sure in correct work of the application’s basic functions before applying the aforementioned techniques.
Also, it is not recommended to apply refactoring in projects with an upcoming deadline.
Currently, refactoring is an alternative to conceptual design which provides a gradual transition from out of date cascade scheme of software development to new, more beneficial “agile” scheme. If your project is in need of constructive and integral approach to the code refactoring – waste no time and employ the experts.
let’s get down to business, to defeat the huns