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Java - Enumeration Interface

The Enumeration interface defines the methods by which you can enumerate (obtain one at a time) the elements in a collection of objects.

This legacy interface has been superceded by Iterator. Although not deprecated, Enumeration is considered obsolete for new code. However, it is used by several methods defined by the legacy classes such as Vector and Properties, is used by several other API classes, and is currently in widespread use in application code.

Enumeration Interface Methods

The methods declared by Enumeration are summarized in the following table −

Sr.No. Method & Description
1

boolean hasMoreElements( )

When implemented, it must return true while there are still more elements to extract, and false when all the elements have been enumerated.
2

Object nextElement( )

This returns the next object in the enumeration as a generic Object reference.

Example 1: Enumeration for Vector

Following is an example showing usage of Enumeration for a Vector.

import java.util.Vector;
import java.util.Enumeration;

public class EnumerationTester {

   public static void main(String args[]) {
      Enumeration<String> days;
      Vector<String> dayNames = new Vector<>();
      
      dayNames.add("Sunday");
      dayNames.add("Monday");
      dayNames.add("Tuesday");
      dayNames.add("Wednesday");
      dayNames.add("Thursday");
      dayNames.add("Friday");
      dayNames.add("Saturday");
      days = dayNames.elements();
      
      while (days.hasMoreElements()) {
         System.out.println(days.nextElement()); 
      }
   }
}

Output

Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday

Example 2: Enumeration for properties

Following is an example showing usage of Enumeration for Properties to print the values.

import java.util.Vector;
import java.util.Enumeration;
import java.util.Properties;

public class EnumerationTester {

   public static void main(String args[]) {
      Enumeration<Object> days;
      Properties dayNames = new Properties();
      
      dayNames.put(1, "Sunday");
      dayNames.put(2,"Monday");
      dayNames.put(3,"Tuesday");
      dayNames.put(4,"Wednesday");
      dayNames.put(5,"Thursday");
      dayNames.put(6,"Friday");
      dayNames.put(7,"Saturday");
      days = dayNames.elements();
      
      while (days.hasMoreElements()) {
         System.out.println(days.nextElement()); 
      }
   }
}

Output

Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
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