/*
 * @(#)Stack.java 1.13 98/09/11  
 *
 * Copyright 1998 Elliotte Rusty Harold.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for all purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies.
 */

package java.util;

/**
 * A stack that guarantees its own integrity.
 *
 * @version   1.0, 12/09/96
 * @author  Elliotte Rusty Harold
 */
public class Stack {
 
  Vector theStack;

  public Object push(Object o) {
  
    theStack.addElement(o);
    return o;
    
  }

  public Object pop() {
  
    Object  o;
    
    int len = theStack.size();
    o = peek();
    theStack.removeElementAt(len - 1);
    return o;
    
  }

  public Object peek() {

    Object  o;
    
    int len = theStack.size();
    if (len == 0) throw new EmptyStackException();
     return theStack.elementAt(len - 1);
     
  }

  public boolean empty() {
  
    if (theStack.size() == 0) return true;
    else return false;
    
  }

  public int search(Object o) {
  
    int i = theStack.lastIndexOf(o);

    if (i >= 0) return theStack.size() - i;
    return -1;
    
    }
    
}