/** * Represents the empty list. * @author Dung X. Nguyen * @version 1.0 * @since 01/22/02 * @Custom Copyright 2002 -All rights reserved */ public class EmptyList extends AList { /** * Throws an IllegalArgumentException. * @return does not return. * @exception IllegalArgumentException. */ public Object getFirst() { throw new IllegalArgumentException ("EmptyList has no first!"); } /** * Throws an IllegalArgumentException * @return does not return. * @exception IllegalArgumentException. */ public AList getRest() { throw new IllegalArgumentException ("EmptyList has no rest!"); } /** * Returns the null String. * @return "". */ public String toString() { return ""; } }