How to create enum type in Java

Description

An enumeration is a list of named constants.

Syntax

An enumeration is created using the enum keyword.

For example, here is a simple enumeration:

enum Direction { 
   East, South, West, North
}

The identifiers East, South are called enumeration constants. Enumeration constants is implicitly declared as a public, static final member of Direction.

Enum type variable

Once you have defined an enumeration, you can create a variable of that type.

Even though enumerations define a class type, you do not instantiate an enum using new.

The following code declares ap as a variable of enumeration type Direction:

Direction ap; 

Because ap is of type Direction, the only values that it can be assigned are those defined by the enumeration. For example, this assigns ap the value South:

ap = Direction.South; 

Compare

Two enumeration constants can be compared for equality by using the == relational operator.

// An enumeration of direction varieties. 
enum Direction {
  East, South, West, North// w w w .j  av a2s  . c  o m
}

public class Main {
  public static void main(String args[]) {
    Direction dir = Direction.South;

    System.out.println("Value of dir: " + dir);

    dir = Direction.South;

    if (dir == Direction.South){
      System.out.println("ap contains GoldenDel.\n");
    }
  }
}

The code above generates the following result.

Enum Switch

An enumeration value can also be used to control a switch statement.

enum Direction {/* ww w.jav a2  s.com*/
  East, South, West, North
}

public class Main {
  public static void main(String args[]) {
    Direction dir = Direction.South;
    switch (dir) {
    case South:
      System.out.println("south");
      break;
    case East:
      System.out.println("East");
      break;
    case West:
      System.out.println("West");
      break;
    case North:
      System.out.println("North.");
      break;
    }
  }
}

The code above generates the following result.