List.java

//Abstraktni razred seznam
 
public abstract class List {
 
  public abstract void makenull()  ;
  public abstract Object first() ;
  public abstract Object last() ;
  public abstract Object next(Object pos) ;
  public abstract Object previous(Object pos) ;
  public abstract Object end() ;
  public abstract Object retrieve(Object pos) ;
  public abstract Object retrieve(int pos) ;
  public abstract void insert(Object x) ;
  public abstract void insert(Object x, Object pos) ;
  public abstract void delete(Object pos) ;
  public abstract boolean overEnd(Object pos) ;
  public abstract boolean empty() ;
 
  public Object locate(Object x) {
    for (Object iter= first() ;  !overEnd(iter) ; iter=next(iter))
      if (x.equals(retrieve(iter)))
          return iter ;
     return null ;
  }
  public void printList() {
    for (Object iter = first() ; ! overEnd(iter) ; iter=next(iter))
       System.out.print(retrieve(iter)+ ", ") ;
    System.out.println();
  }
  public int len() {
      int n = 0 ;
      for (Object iter = first() ; ! overEnd(iter) ; iter=next(iter))
          n++ ;
      return n ;
    }
  public void copy(List init) {
      makenull() ;
      for (Object iter = init.first() ; ! init.overEnd(iter) ; iter=init.next(iter))
         insert(init.retrieve(iter), last()) ;
  }
}