Collections, Maps and Iterators - Absolute Java - page 928

Display 16.13 An Iterator

1 import java.util.HashSet;
2 import java.util.Iterator;

3 public class HashSetIteratorDemo
4 {
5 public static void main(String[] args)
6 {
7 HashSet<String> s = new HashSet<String>();

8 s.add("health");
9 s.add("love");
10 s.add("money");

11 System.out.println("The set contains:");

12 Iterator<String> i = s.iterator();
13 while (i.hasNext())
14 System.out.println(i.next());

15 i.remove();

16 System.out.println();
17 System.out.println("The set now contains:");

You cannot “reset” an iterator “to the
beginning.” To do a second iteration,
you create another iterator.

18 i = s.iterator();
19 while (i.hasNext())
20 System.out.println(i.next());

21 System.out.println("End of program.");
22 }
23 }

Sample Dialogue

The set contains:
money
love
health
The set now contains:
money
love
End of program.

The HashSet<T> object
does not order the
elements it contains, but
the iterator imposes an
order on the elements.