Java Collection: EnumSet

It is a specialized implementation of a Set interface for enumeration data types.

A few important facts about EnumSet are as follows:

1. It is not synchronized.
2. It is much faster than HashSet.
3. All keys must be keys of a single enum type.
4. It doesn't allow a null key, though null values are permitted.

Hierarchy of EnumSet class

It extends AbstractSet and implements Set Interface in Java.

Source code of TestMain.java

package com.t4b.test; import java.util.EnumSet; import java.util.Iterator; public class TestMain { public enum WeekDays { Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday }; public static void main(String[] args) { EnumSet<WeekDays> enumset = EnumSet.of(WeekDays.Sunday, WeekDays.Saturday); enumset.add(WeekDays.Wednesday); enumset.add(WeekDays.Tuesday); Iterator<WeekDays> itr = enumset.iterator(); while (itr.hasNext()) { System.out.println(itr.next()); } } }

Happy Exploring!