Associate enum value to integer

Question

I have this enum:

public enum Digits {
    ZERO(0);

private final int number;

    private Digits(int number) {
        this.number = number;
    }

    public int getValue(){
        return number;
    }
}

And I would like to make setter in another class which can me offer following feature: - I will give it integer value (in this case, 0) and that setter will set enum ZERO to my local variable of type Digits Is that possible? Many thanks!

Answer 1

It is possible, but not by invoking the enum's constructor, as it's available only within the enum itself.

What you can do is add a static method in your enum that retrieves the correct instance based on a given value, e.g. ZERO if the given value is 0.

Then you'd invoke that method in your other class when given the int argument.

Self contained example

public class Main {
    static enum Numbers {
        // various instances associated with integers or not
        ZERO(0),ONE(1),FORTY_TWO(42), DEFAULT;
        // int value
        private int value;
        // empty constructor for default value
        Numbers() {}
        // constructor with value
        Numbers(int value) {
            this.value = value;
        }
        // getter for value
        public int getValue() {
            return value;
        }
        // utility method to retrieve instance by int value
        public static Numbers forValue(int value) {
            // iterating values
            for (Numbers n: values()) {
                // matches argument
                if (n.getValue() == value) return n;
            }
            // no match, returning DEFAULT
            return DEFAULT;
        }
    }
    public static void main(String[] args) throws Exception {
        System.out.println(Numbers.forValue(42));
        System.out.println(Numbers.forValue(10));
    }
}

Output

FORTY_TWO
DEFAULT