Using lombok @Getter annotation with Java enum

Question

I am trying to use an enum as a map to retrieve country names from alpha-2 country codes. I have an enum class like so:

public enum Country {
    AF("Afghanistan");

    @Getter
    private final String fullName;

    private Country(String fullName) {
      this.fullName = fullName;
    }

}

I would expect that if I instantiated a new Country object like so

String country = new Country("AF").getFullName();

The variable country should be set to "Afghanistan", but I am getting an error that the object cannot be Country cannot be instantiated.

try `AF.getFullName()` ;) (enum constructors must all be invoked within the enum... ...without "new" keyword!; ... so `AF("Afghanistan")` is the enum(instance) declaration + constructor invocation) — xerx593, Apr 22 '20 at 18:00
problem is I would ideally like to use a variable in place of the hardcoded string `String country = new Country(countryCode).getFullName();`. — Evan Gertis, Apr 22 '20 at 18:02
Either use `Country.AF`, or `Country.valueOf("AF")`. Also, this has nothing to do with Lombok, you only use that to generate a getter. — Mark Rotteveel, Apr 22 '20 at 18:06
if you want the `AF` Country from the String `"AF"`, you can use: `Country.valueOf("AF")` ..if you need this functionality for full name, you'd have to implement. — xerx593, Apr 22 '20 at 18:08

score 1 · Answer 1 · answered Apr 22 '20 at 17:58

1

check this https://stackoverflow.com/a/16851422/3874879 Enums cannot be instantiated, they are like a constant, you must define them at compile time, I guess

answered Apr 22 '20 at 17:58

Mateus Carvalho

48
6

score 1 · Answer 2 · answered Apr 22 '20 at 18:01

An enum is a special "class" that represents a group of constants (unchangeable variables, like final variables).

You can access enum constants with the dot syntax:

String country = Country.AF.getFullName();

Enum constants are public, static and final. You cannot create enum instances using new.

Enum constants (AF in your case) are the only instances you can use.

a.eugene · Answer 3 · 2020-04-22T18:10:28.850

You cannot create an object.

Check this documentation: https://docs.oracle.com/javase/7/docs/api/java/lang/Enum.html

And try this: String country = Country.AF.getFullName();

EDIT: If you want to use a variable in place of the hardcoded string you can define some method like findByCountryCode(countryCode) in your enum

public Country findByCountryCode(String code) {
    for (Country value : Country.values()) {
        if (value.getFullName().equals(code)) {
            return value;
        }
    }
    return null;
}

Using lombok @Getter annotation with Java enum

3 Answers3