/* An instance of this class represents a non-empty list of items.
**
** Author: R. McCloskey, November 2019
*/

public class RecursiveListNonEmpty<T> implements RecursiveList<T> {

   // instance variables
   // ------------------
   private T head;
   private RecursiveList<T> tail;

   // constructors
   // ------------

   public RecursiveListNonEmpty(T item) { 
      this(item, RecursiveListEmpty.emptyListFactory()); }
      //this(item, new RecursiveListEmpty()); }

   public RecursiveListNonEmpty(T item, RecursiveList<T> list) {
      head = item;
      tail = list;
   }

   public boolean isEmpty() { return false; }

   public T headOf() { return head; }

   public RecursiveList<T> tailOf() { return tail; }

   public String toString() {
      return "< " + headOf() + " " + tailOf().toString() + ">";
   }

   public RecursiveList<T> cons(T item) {
      return new RecursiveListNonEmpty<T>(item, this);
   }

   public RecursiveList<T> emptyList() { 
      return RecursiveListEmpty.emptyListFactory();
      //return new RecursiveListEmpty<T>();
   }
}