Using Object-Oriented Patterns - Beginning Java Programming: The Object-Oriented Approach - page 606

String name = iterator.next();
System.out.println(name);
if (name.startsWith("A")) {
iterator.remove();
System.out.println(" ... removed");
}
}
}
}
What if you want to create a list returning a backward looping iterator? Just extend the built‐in
List class, extending the iterator() method to return your own iterator. If you want to create a
list that can return both iterators, it's easiest to extend the List class with a separate method, as is
done in the following snippet:
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class IteratorTest {
public static void main(String[] args) {
BackwardsList<String> list = new BackwardsList<>();
list.add("Bart");
list.add("Aimee");
list.add("Seppe");
Iterator<String> iterator = list.getBackwardsIterator();
while (iterator.hasNext()) {
String name = iterator.next();
System.out.println(name);
if (name.startsWith("A")) {
iterator.remove();
System.out.println(" ... removed");
}
}
}
public static class BackwardsList<T> extends ArrayList<T> {
public Iterator<T> getBackwardsIterator() {
final List<T> arrayList = this;
Iterator<T> iterator = new Iterator<T>() {
private int currentIndex = arrayList.size()-1;
@Override
public boolean hasNext() {
return currentIndex >= 0;
}
@Override
public T next() {
return arrayList.get(currentIndex--);
}
@Override
public void remove() {
arrayList.remove(currentIndex+1);
}