The Java Language Specification, Third Edition

CLASSES Enums 8.9
Note that the example can easily be refactored to work properly:
enum Color {
RED, GREEN, BLUE;
static final Map colorMap =
new HashMap();
static {
for (Color c : Color.values())
colorMap.put(c.toString(), c);
}
}
The refactored version is clearly correct, as static initialization occurs top to bottom.
DISCUSSION
Here is program with a nested enum declaration that uses an enhanced for loop to iterate
over the constants in the enum:
public class Example1 {
public enum Season { WINTER, SPRING, SUMMER, FALL }
public static void main(String[] args) {
for (Season s : Season.values())
System.out.println(s);
}
}
Running this program produces the following output:
WINTER
SPRING
SUMMER
FALL
Here is a program illustrating the use of EnumSet to work with subranges:
import java.util.*;
DRAFT
public class Example2 {
enum Day { MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATUR-
DAY, SUNDAY }
}
public static void main(String[] args) {
System.out.print("Weekdays: ");
for (Day d : EnumSet.range(Day.MONDAY, Day.FRIDAY))
System.out.print(d + " ");
System.out.println();
}
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