CODEWITHSUNDEEP
javaconstants
lugiank
lugiank

Reputation: 81

Treating class as a constant

abstract class Coin{
    String name;
    String currency;


    class EUR extends Coin{
        EUR() {
        super("EUR", "€");
        }

    }
    class USD extends Coin{
        USD() {
        super("USD", "$");
        }

    }

    private Coin (String name, String currency){
    this.name = name
    this.currency = currency}
    }

class Person{
    ///variables
    Coin coin;

    Person(//Variables, Coin coin){
        //Other assignments
        this.coin = coin
    }

}

Basically i would like to initialize a Person passing EUR as Coin, without creating a new EUR. Something like

static final EUR euro = EUR

and then:

Person person = new Person(... , euro);

I do not need millions of instances of EUR so i don't want to create each time a new EUR

I know i can make something like this using constant Strings, but i actually want to pass a Coin object

I also tried initializing EUR inside Coin class like this

static EUR euro = new EUR();

But IDE is warning me this could cause thread deadlock

Upvotes: 2

Views: 60

Answers (1)

Mureinik
Mureinik

Reputation: 312106

This is a perfect job for an enum:

public enum Coin {
    EUR("EUR", "€"),
    USD("USD", "$");

    private String name;
    private String currency;

    private Coin(String name, String currency) {
        this.name = name;
        this.currency = currency;
    }
}

Once you've defined it, you can use the enum constants:

Person person = new Person(... , Coin.EUR);

Upvotes: 5

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