package util.list;

import java.util.NoSuchElementException;

import util.list.Iterator;

public class ListIterator implements Iterator {

  private List     myList = null;
  private ListLink cursor = null;

  ListIterator(List aList) {
    myList = aList;
    start();
  }

  public void start() {
    cursor = myList.getHead();
  }

  public boolean cont() {
    return cursor != null;
  }

  public void next() {
    cursor = cursor.getNext();
  }

  public Object getCurrent() {
    return cursor.getInfo();
  }

  public Object getNext() throws NoSuchElementException {
    if (!hasNext())
      throw new NoSuchElementException();
    
    return cursor.getNext().getInfo();
  }

  public boolean hasNext() {
    return (cont() && cursor.getNext() != null);
  }

  public void insertNext(Object info) {
    cursor.setNext(new ListLink(info, cursor.getNext()));
  }

  public void removeNext() throws NoSuchElementException {
    if (!hasNext())
      throw new NoSuchElementException();

    cursor.setNext(cursor.getNext().getNext());
  }
}