Coding Conventions - Naming Enums

java

naming-conventions

enums

best-practices

byNikita Barsukov·Aug 8, 2024

In Java, enums should follow a UPPER_CASE naming convention just like constants. This reinforces their immutable nature in the eyes of fellow developers and aligns with the Java Language Specification:

public enum Color {
    RED,    // as red as an embarrassed tomato
    GREEN,  // as green as Kermit the Frog
    BLUE;   // as blue as a smurf's bottom
}

For enums with compound names, remember that readability is king. Therefore, you can opt for UPPER_CASE or play with Mixed_Case to make it easy on the eyes:

public enum HttpStatus {
    OK,    // when everything is just fine and dandy
    NOT_FOUND,  // hide and seek champion
    BAD_REQUEST; // smelly requests end up here
}

Using meaningful and descriptive names is better than sticking a dull "Enum" at the end.

Avoid confusion with class naming

Sometimes, enums could share a similar identity with a class, causing a naming clash. To avoid confusion, differentiate with context and usage:

public class NetworkConnection {  // this class is doing all the hard work
    ...
}

public enum NetworkConnectionType { // the VIP list of network connections
    WIFI, ETHERNET, LTE;
}

With distinguishable and clear names, one can easily tell a model or utility (NetworkConnection) apart from a set of predefined options (NetworkConnectionType).

Balancing brevity and clarity

In your pursuit of the perfect enum name, always strike a balance between brevity and descriptiveness:

public enum State {
    NEW,     // fresh out of the oven
    ACTIVE,  // out and about
    INACTIVE, // low energy saving mode
    DELETED;  // guess who saw the grim reaper
}

// Instead of
public enum StateOfObject {
    STATE_NEW, STATE_ACTIVE, STATE_INACTIVE, STATE_DELETED;  // verbosity at its finest
}

State is simple and conveys as much information as the verbose StateOfObject.

Making it chime with methods

Remember that the naming choice for enums can affect their interaction with certain methods like .name(), which returns the enum constant's name as a String:

public enum Fruit {
    APPLE,   // An apple a day...
    BANANA,  // and a banana for breakfast!
    CHERRY;  // save the cherry for last
}

Fruit cherry = Fruit.CHERRY;
System.out.println(cherry.name()); // Prints "CHERRY"