OnJava8-Examples/containers/CollectionSequence.java

// containers/CollectionSequence.java
import typeinfo.pets.*;
import java.util.*;

public class CollectionSequence
extends AbstractCollection<Pet> {
  private Pet[] pets = Pets.createArray(8);
  @Override
  public int size() { return pets.length; }
  @Override
  public Iterator<Pet> iterator() {
    return new Iterator<Pet>() {
      private int index = 0;
      @Override
      public boolean hasNext() {
        return index < pets.length;
      }
      @Override
      public Pet next() { return pets[index++]; }
      @Override
      public void remove() { // Not implemented
        throw new UnsupportedOperationException();
      }
    };
  }
  public static void main(String[] args) {
    CollectionSequence c = new CollectionSequence();
    InterfaceVsIterator.display(c);
    InterfaceVsIterator.display(c.iterator());
  }
}
/* Output:
0:Rat 1:Manx 2:Cymric 3:Mutt 4:Pug 5:Cymric 6:Pug 7:Manx
0:Rat 1:Manx 2:Cymric 3:Mutt 4:Pug 5:Cymric 6:Pug 7:Manx
*/