Is It Considered Clean Code to Define Functions Within Enums?

Is it considered good practice to define functions within enumerations in programming?

enum UserRole {
    ADMIN, 
    USER;

    public String getRoleDescription() {
        return this == ADMIN ? "Administrator" : "Regular User";
    }
}

Defining functions within enums is a topic of debate in software engineering. While it can improve encapsulation and readability in some cases, it can also complicate the code structure if overused or misused.

public enum UserRole {
    ADMIN, 
    USER;

    public String getRoleDescription() {
        return this == ADMIN ? "Administrator" : "Regular User";
    }
}

Causes

• Enums are primarily intended to represent a fixed set of constants, not to encapsulate behavior.
• Including methods in enums can lead to confusion about their primary purpose, which is to define a type.

Solutions

• Implement behavior in separate utility classes instead of mixing it with enum definitions.
• Use enums with associated behavior sparingly and only when it enhances readability and maintainability of the code.

Mistake: Overloading enums with too many methods, making them hard to read.

Solution: Keep the number of methods minimal and related directly to the enum's purpose.

Mistake: Using enums for expansive functionality beyond constant definitions.

Solution: Limit enum usage to constant values and small amounts of behavior that don't overshadow their primary role.