Kode Java

How do I define a field in enum type?

Category: fundamental, viewed: 699 time(s).

As we know that Java enumeration type is powerful compared to enum implementation in other programming language. Basically enum is class typed so it can have constructors, methods and fields.

In the example below you'll see how a field is defined in an enumeration type. Because each constant value for the Fruit enum is a type of Fruit itself it will have its own price field. The price field holds a unique value for each constant such as APPLE, ORANGE, etc.

In the result you'll see that the constructor will be called for each constant value and initialize it with the value passed to the constructor.

package org.kodejava.example.fundametal;

enum Fruit {
    APPLE(1.5f), ORANGE(2), MANGGO(3.5f), GRAPE(5);

    private float price;

    Fruit(float price) {
        System.out.println("Name: " + this.name() + " initialized.");
        this.price = price;
    }

    public float getPrice() {
        return this.price;
    }
}

public class EnumFieldDemo {
    public static void main(String[] args) {
        //
        // Get the name and price of all enum constant value.
        //
        for (Fruit f : Fruit.values()) {
            System.out.println("Fruit = " + f.name() + "; Price = " + f.getPrice());
        }
    }
}

Our demo result is below:

Name: APPLE initialized.
Name: ORANGE initialized.
Name: MANGGO initialized.
Name: GRAPE initialized.
Fruit = APPLE; Price = 1.5
Fruit = ORANGE; Price = 2.0
Fruit = MANGGO; Price = 3.5
Fruit = GRAPE; Price = 5.0