DataStructure.java

public class DataStructure{
    private final static int SIZE = 15;
    private int[] arrayOfInts = new int[SIZE];

    public DataStructure(){
        for(int i = 0; i < SIZE; i++) arrayOfInts[i] = i;
    }

    public void printEvent(){
        DataStructureIterator iterator = this.new EvenIterator();

        while(iterator.hasNext()) System.out.print(iterator.next() + " ");
        System.out.println();
    }

    interface DataStructureIterator extends java.util.Iterator<Integer>{}

    private class EvenIterator implements DataStructureIterator{
        private int nextIndex = 0;

        public boolean hasNext(){ return (nextIndex <= SIZE - 1); }
        public Integer next(){
            Integer retValue = Integer.valueOf(arrayOfInts[nextIndex]);
    
            nextIndex += 2;
            return retValue;
        }
    }

    public static void main(String s[]){
        DataStructure ds = new DataStructure();
        ds.printEvent();
    }
}