Convert an enumeration to set in Java

Write a function toSet, that takes an Enumeration as an argument and return the set as output.

 

Signature

public static <T> Set<T> toSet(Enumeration <T> iterator)

 

Find the below working application

 

EnumerationToSet.java

package com.sample.app.collections;

import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.Vector;

public class EnumerationToSet {

	/**
	 * Convert an {@link Enumeration} to the {@link Set}
	 * 
	 * @param <T>
	 * @param iterator
	 * 
	 * @return empty set, if the Enumeration is null, else return a set that contain
	 *         the elements from Enumeration
	 */
	public static <T> Set<T> toSet(Enumeration<T> enumeration) {

		if (enumeration == null) {
			return Collections.emptySet();
		}

		final Set<T> set = new HashSet<>();

		while (enumeration.hasMoreElements()) {
			set.add(enumeration.nextElement());
		}

		return set;
	}

	public static void main(String[] args) {
		final Vector<Integer> primesVector = new Vector<>();
		primesVector.addAll(Arrays.asList(2, 3, 5, 7, 11));

		final Enumeration<Integer> primesEnumeration = primesVector.elements();
		System.out.println(toSet(primesEnumeration));
	}

}

 

Output

[2, 3, 5, 7, 11]

 

 

  

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