//////////////////////////////////////////////////////////////////////
// Printable

interface Printable {
    public void print();
}

//////////////////////////////////////////////////////////////////////
// INTERFACES
// Without these, clients would not be able to treat named list cells
// as list cells, because NamedListCell does not extend ListCell (see
// below).

interface IListCell<Elem> {
    public Elem getValue();
    public IListCell next();
}

interface INamedListCell<Elem> 
    extends IListCell<Elem>
{
    public INamedListCell<Elem> nextNamed();
}

//////////////////////////////////////////////////////////////////////
// MYTYPE-PARAMETERIZED CLASSES

abstract class PListCell<Elem,
                         MyType extends PListCell<Elem, MyType>>
  implements IListCell<Elem>
{
  protected final Elem value;
  protected final MyType next;

  public PListCell(Elem value, MyType next) {
    this.value = value;
    this.next = next;
  }
  public Elem getValue() { return value; }
  public MyType next() { return next; }
}

abstract class PNamedListCell<Elem extends Printable,
                              MyType extends PNamedListCell<Elem, MyType>>
    extends PListCell<Elem, MyType>
    implements INamedListCell<Elem>
{
  public PNamedListCell(Elem value, MyType next) {
      super(value, next);
  }
  public INamedListCell<Elem> nextNamed() {
    return next;
  }
  public void printAll() {
    this.getValue().print();
    this.next().printAll();
  }
}

//////////////////////////////////////////////////////////////////////
// CONCRETE CLASSES
// Without these, you would not be able to have a finite instantiation
// of the parameterized classes.

class ListCell<Elem>
    extends PListCell<Elem, ListCell<Elem>>
{
    public ListCell(Elem value, ListCell<Elem> next) { super(value, next); }
}

class NamedListCell<Elem extends Printable>
    extends PNamedListCell<Elem, NamedListCell<Elem>>
{
    public NamedListCell(Elem value, NamedListCell<Elem> next) { super(value, next); }
}

//////////////////////////////////////////////////////////////////////
// CLIENT

class C implements Printable {
    public void print() { System.out.println("C"); }
}

public class GJRecursive
{
  public static void main(String[] args) {
      IListCell<C> cell = new NamedListCell<C>(new C(), null);
      INamedListCell<C> cell2 = new NamedListCell<C>(new C(), null);
      INamedListCell<C> cell3 = cell2.nextNamed();
  }
}