Java Enum Class with Values: A Comprehensive Guide

In Java programming, an enum class is a special kind of class that allows you to define a fixed set of constant values. These constant values can be used to represent different states, directions, days of the week, colors, and many more. In this article, we will explore the concept of enum classes in Java, their benefits, and how they are implemented.

Defining an Enum Class

An enum class is defined using the `enum` keyword followed by the name of the class. For example, you can define an enum class for contract status with values like 'permanent', 'temp', and 'intern':

```

public enum ContractStatus {

PERMANENT,

TEMP,

INTERN;

}

```

Note that the semicolon at the end of each constant value is optional.

Methods in Enum Class

The Java compiler internally adds three methods to every enum class: `ordinal()`, `valueOf()`, and `values()`. These methods are used to retrieve information about the enum values.

* The `ordinal()` method returns the index of the enum value. For example, if you have an enum class with values 'A', 'B', and 'C', then `ordinal('B')` would return 1.

* The `valueOf()` method returns the value of a given constant enum. For example, if you have an enum class with values 'RED', 'GREEN', and 'BLUE', then `valueOf('GREEN')` would return the value 'GREEN'.

* The `values()` method returns an array containing all the values of the enum.

Fields, Constructors, and Methods in Enum Class

Unlike regular classes, enum classes can have fields, constructors, and methods. You can define a constructor to initialize the enum values, or define methods to perform specific operations.

For example:

```

public enum Color {

RED(255, 0, 0),

GREEN(0, 255, 0),

BLUE(0, 0, 255);

private int red;

private int green;

private int blue;

Color(int red, int green, int blue) {

this.red = red;

this.green = green;

this.blue = blue;

}

public void printColor() {

System.out.println('Red: ' + red);

System.out.println('Green: ' + green);

System.out.println('Blue: ' + blue);

}

```

Benefits of Enum Classes

Enum classes have several benefits over traditional constant values. They provide a way to group related constants together, making it easier to maintain and extend your code. They also provide a way to perform operations on the constants, such as retrieving their index or value.

In addition, enum classes are more powerful than traditional constant values because they can implement interfaces but not extend classes.

In this article, we have seen how to define an enum class in Java and its benefits. We have also explored the methods that the Java compiler adds to every enum class and how you can use them to retrieve information about the enum values. By using enum classes, you can create more robust and maintainable code.

Java enum class with values