out.println("  
" + currentPrimes.elementAt(i));

    }

    out.println("");

    out.println("");

  }

  public void doPost(HttpServletRequest request,

                     HttpServletResponse response)

      throws ServletException, IOException {

    doGet(request, response);

  }

  // See if there is an existing ongoing or completed

  // calculation with the same number of primes and number

  // of digits per prime. If so, return those results instead

  // of starting a new background thread. Keep this list

  // small so that the Web server doesn't use too much memory.

  // Synchronize access to the list since there may be

  // multiple simultaneous requests.

  private PrimeList findPrimeList(Vector primeListVector,

                                  int numPrimes,

                                  int numDigits) {

    synchronized(primeListVector) {

      for(int i=0; i