package hall; import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.util.*; /** * Part of tutorial on servlets and JSP that appears at * http://www.apl.jhu.edu/~hall/java/Servlet-Tutorial/ * 1999 Marty Hall; may be freely used or adapted. */ public class PrimeNumbers extends HttpServlet { private static PrimeList primeList; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { log("Entered PrimeNumbers!"); int numPrimes = ServletUtilities.getIntParameter(request, "numPrimes", 50); int numDigits = ServletUtilities.getIntParameter(request, "numDigits", 120); int numPrimesPrinted = ServletUtilities.getIntParameter(request, "numPrimesPrinted", -1); if (numPrimesPrinted > numPrimes) numPrimesPrinted = 0; if ((numPrimesPrinted == -1) || (primeList == null)) { primeList = new PrimeList(numPrimes, numDigits, true); } Vector currentPrimes = primeList.getPrimes(); int numCurrentPrimes = currentPrimes.size(); if (true || (numPrimesPrinted < numCurrentPrimes)) buildPrimeTable(response, numPrimes, numDigits, currentPrimes, numCurrentPrimes); else { String url = "http://hallmr1/servlet/hall.PrimeNumbers?" + "numPrimes=" + numPrimes + "&numDigits=" + numDigits + "&numPrimesPrinted=" + currentPrimes.size(); response.setHeader("Refresh", "5; URL=" + url); response.setHeader("Retry-After", "5"); response.setHeader("Location", url); response.setStatus(response.SC_NO_CONTENT); //response.setStatus(response.SC_RESET_CONTENT); } } public void buildPrimeTable(HttpServletResponse response, int numPrimes, int numDigits, Vector currentPrimes, int numCurrentPrimes) throws IOException { int numPrimesRemaining = (numPrimes - numCurrentPrimes); boolean isLastResult = (numPrimesRemaining == 0); if (!isLastResult) { // TO DO: How to build URL to self? String url = "http://hallmr1/servlet/hall.PrimeNumbers?" + "numPrimes=" + numPrimes + "&numDigits=" + numDigits + "&numPrimesPrinted=" + currentPrimes.size(); response.setHeader("Refresh", "5; URL=" + url); } response.setContentType("text/html"); PrintWriter out = response.getWriter(); String title = "Some " + numDigits + "-Digit Prime Numbers (back to 204)"; out.println(ServletUtilities.headWithTitle(title) + "\n" + "

" + title + "

\n" + "

Primes found with " + numDigits + " or more digits: " + numCurrentPrimes + ".

"); if (isLastResult) out.println("Done searching."); else out.println("Still looking for " + numPrimesRemaining + " more..."); out.println("
    "); for(int i=0; i" + currentPrimes.elementAt(i)); } out.println("
"); out.println(""); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }