/**
 * CircularList.java
 *
 * This class implements a circular list using the Vector class
 * note that elements in a vector with n elements are numbered 0 .. (n-1)
 *
 * @author Greg Gagne, Peter Galvin, Avi Silberschatz
 * @version 1.0 - July 15, 1999.
 * Copyright 2000 by Greg Gagne, Peter Galvin, Avi Silberschatz
 * Applied Operating Systems Concepts - John Wiley and Sons, Inc.
 */

import java.util.*;

public class CircularList 
{
   private Vector List;
   private int index;
   
   public CircularList() {
      List = new Vector(10);
      index = 0;
   }
   
   /**
    * this method returns the next element in the list.
    * @return Object
    */
   public Object getNext() {
      Object nextElement = null;
      int lastElement;
      
      if (!List.isEmpty() ) {
         if (index == List.size() )
            index = 0;
         
         nextElement = List.elementAt(index);
         
         ++index;
      }
         
      return nextElement;
   }
   
   /**
    * this method adds an item to the list
    * @return void
    */
   public void addItem(Object t) {
      List.addElement(t);      
   }

}