Clean Code: Naming Conventions

A series of blog posts based on Robert C. Martin’s book “Clean code : a handbook of agile software craftsmanship“.

You can find the book here.

As a programmer, we are going to be naming lots of variables, classes, and methods. According to Uncle Bob in Clean Code, we should name a variable with the same care we do in naming a first-born child. After all, we are going to need to be able to call it, know what it’s for, and not confuse it with any other variables in our classes.

When we name with care, we name with “intention-revealing” names. Naming well saves you more time in the long run, saves everyone more time, and prevents a snowball of bad things happening to your precious code. The names we choose should answer the big questions:

Why does it exist?
What does it do?
How is it used?

Good and bad naming examples in code.

We need to be able to tell what the code is doing. In the example picture, it is very easy to see what the purpose is of the last three names versus the first name. Explicit names help immediately see what is going on in the code. If you MUST use a single letter name, it is best practice to use it as a local variable inside a short method. The length of a name should correspond to the size of its scope.

Using a name like h, we would have to mentally map what this variable is doing, translating it in our brain to what it actually does, using much more memory. Clarity is king. Use your powers for good naming practices to write code that everyone can understand. Pretend like the next person who will read your code is a violent psychopath who knows your address. It’s serious business!

Class and Method Names

This is something that needs to be written on your computer or tattooed on your arm or put anywhere you can see it, like an affirmation you are practicing, only programmer edition.

Photo by ThisIsEngineering on Pexels.com

Class names should have a noun or noun phrase. Class names should not be verbs.

Methods should have verb or verb phrases. Accessors, mutators, and predicates should be named for their value and prefixed with get, set, and is according to the javabean standard.
(“Oracle Java Technologies | Oracle,” 2019).

Don’t be cute in naming. Clever names are memorable only to people who share the same humor and some of us are the only ones laughing at our jokes. I know I’m funny, but others may not think so. Clarity is more important than entertainment. Our cleverness only goes so far as our cultural slang. Naming something dirtNap() meaning kill() or wipeout() meaning DeleteItems() is cute, but the latter is understood by all. A consistent lexicon is worth its weight in gold for the programmers who must use your code.

Other Important Naming Concepts

Pick one word for an abstract concept and stick with it. Using fetch, retrieve, and get as similar methods in different classes goes back to using too much mental memory. Ask yourself some questions about what these methods are doing and see if they are all serving the same purpose to choose an appropriate word.

Don’t Pun. Converse to using one word per abstract concept, do not use the same word for two purposes. Doing so would be a pun. Using “one word per concept”, could end up with a lot of classes using an “add” method as described in the book. If we are using the word for consistency rather than intent, it can get very confusing. Ask yourself what the method is actually doing so you know if you need to name it “insert” or “append”.

Use Solution Domain Names. Programmers will be reading your code so go ahead and use terms that other programmers understand like algorithm names, math terms, and pattern names.

Use Problem Domain Names. Problem domains refers to all the information that defines the problem (i.e. the problem you are solving with code). If there are no programming or computer science terms for what the code is doing, use the name from the problem domain. Good programmers and designers have the important task of separating solution and problem domain concepts.

Photo by Startup Stock Photos on Pexels.com

Add Meaningful Context, But Not Gratuitous Context. Most of the time we have successfully added meaningful context by using good naming, separation of concerns, and well-defined classes. As a last resort, you may have to add some prefixing. If you saw firstName, lastName, street, houseNumber, city, state, and zipcode in a method, you would assume it’s an address. If city was used alone in a method, would you assume it’s part of an address? The context can be added by prefixing with addrState, addrCity, etc so it’s explicitly part of an address.

This doesn’t mean to do this always. Adding gratuitous context can be very confusing, like prefixing every method with the acronym of the application. “ABCFirstName, ABCLastName, ABCStreetAddress” are too much. Shorter names are generally better than long ones when they are clear.

Following some of these rules and asking yourself the important questions about your code will help get you thinking about what and why you are naming things and keeping the code understandable for all, saving you many headaches in the future. Happy coding!

References:

Oracle Java Technologies | Oracle. (2019). Retrieved March 29, 2020, from Oracle.com website: https://www.oracle.com/java/technologies/

Martin, R. C. (2009). Clean code: A handbook of agile software craftsmanship. Upper Saddle River, NJ: Prentice Hall.




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