enum type with its own method : enum « Data Type « Java Tutorial

public class SizeIterator {

  public static void main(String[] args) {
    Size[] sizes = Size.values();
    for (Size s : sizes) {

enum Size implements Countable {
  S, M, L, XL, XXL, XXXL;
  public Size increase() {
    Size sizes[] = this.values();
    int pos = this.ordinal();
    if (pos < sizes.length - 1)
    return sizes[pos];

interface Countable {
  public Size increase();

2.43.1.Enumeration Fundamentals
2.43.2.How to define an enumeration
2.43.3.Enums in a Class
2.43.4.equals and = operator for enum data type
2.43.5.Comparing Enumeration Values
2.43.6.Two enumeration constants can be compared for equality by using the == relational operator
2.43.7.uses an enum, rather than interface variables, to represent the answers.
2.43.8.enum type with its own method
2.43.9.Enum type field
2.43.10.enum with switch