public void init() throws ServletException {
ServletContext ctx = getServletContext();
remoteHost =
ctx.getInitParameter("RMI_SERVER"); // Reads the value from the <context-param> in web.xml
mh = new MessageHandler(); // Instantiate message handler on service start
vmh =
new VigenereRequestManager(
mh.getQueue(),
mh.getMap(),
remoteHost); // Instansiate Request manager at service start with references to same
// queue and map as message handler
executorService.execute(vmh); // Run the Request service daemon
}
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("text/html");
PrintWriter out = resp.getWriter();
int maxKeyLength = Integer.parseInt(req.getParameter("frmMaxKeyLength"));
String cypherText = req.getParameter("frmCypherText");
String taskNumber = req.getParameter("frmStatus");
String plainText = null; // Holder for returned test
out.print("<html><head><title>Distributed Systems Assignment</title>");
out.print("</head>");
out.print("<body>");
if (taskNumber == null) {
jobNumber++;
taskNumber = new String("T" + jobNumber + " Quelength " + q.isEmpty());
// Make message object from input text
final OutMessage message = new OutMessage(jobNumber, cypherText, maxKeyLength);
// pass message to handler and onto queue in its own thread from pool
executorService.execute(
new Runnable() {
public void run() {
mh.add(message);
}
});
} else {
// Check out-queue for finished job
// copy plain text to string cypher2 to appear on page
plainText = mh.get(jobNumber);
}
out.print("<H1>Processing request for Job#: " + taskNumber + "</H1>");
out.print("<div id=\"r\"></div>");
out.print("RMI Server is located at " + remoteHost);
out.print("<P>Maximum Key Length: " + maxKeyLength);
out.print("<P>CypherText: " + cypherText);
out.print("<P>Decoded: " + plainText);
out.print(
"<P>This servlet should only be responsible for handling client request and returning responses. Everything else should be handled by different objects.");
out.print(
"<P>Note that any variables declared inside this doGet() method are thread safe. Anything defined at a class level is shared between HTTP requests.");
out.print("<P> Next Steps:");
out.print("<OL>");
out.print(
"<LI>Generate a big random number to use a a job number, or just increment a static long variable declared at a class level, e.g. jobNumber");
out.print(
"<LI>Create some type of a message request object from the maxKeyLength, cypherText and jobNumber.");
out.print("<LI>Add the message request object to a LinkedList or BlockingQueue (the IN-queue)");
out.print(
"<LI>Return the jobNumber to the client web browser with a wait interval using <meta http-equiv=\"refresh\" content=\"10\">. The content=\"10\" will wait for 10s.");
out.print("<LI>Have some process check the LinkedList or BlockingQueue for message requests ");
out.print(
"<LI>Poll a message request from the front of the queue and make an RMI call to the Vigenere Cypher Service");
out.print(
"<LI>Get the result and add to a Map (the OUT-queue) using the jobNumber and the key and the result as a value");
out.print(
"<LI>Return the cyphertext to the client next time a request for the jobNumber is received and delete the key / value pair from the Map.");
out.print("</OL>");
out.print("<form name=\"frmCracker\">");
out.print("<input name=\"frmMaxKeyLength\" type=\"hidden\" value=\"" + maxKeyLength + "\">");
out.print("<input name=\"frmCypherText\" type=\"hidden\" value=\"" + cypherText + "\">");
out.print("<input name=\"frmStatus\" type=\"hidden\" value=\"" + taskNumber + "\">");
out.print("</form>");
out.print("</body>");
out.print("</html>");
out.print("<script>");
out.print("var wait=setTimeout(\"document.frmCracker.submit();\", 10000);");
out.print("</script>");
/*-----------------------------------------------------------------------
* Next Steps: just in case you removed the above....
*-----------------------------------------------------------------------
* 1) Generate a big random number to use a a job number, or just increment a static long variable declared at a class level, e.g. jobNumber
* 2) Create some type of a "message request" object from the maxKeyLength, cypherText and jobNumber.
* 3) Add the "message request" object to a LinkedList or BlockingQueue (the IN-queue)
* 4) Return the jobNumber to the client web browser with a wait interval using <meta http-equiv="refresh" content="10">. The content="10" will wait for 10s.
* 4) Have some process check the LinkedList or BlockingQueue for "message requests"
* 5) Poll a "message request" from the front of the queue and make an RMI call to the Vigenere Cypher Service
* 6) Get the result and add to a Map (the OUT-queue) using the jobNumber and the key and the result as a value
* 7) Return the cyphertext to the client next time a request for the jobNumber is received and delete the key / value pair from the Map.
*/
// You can use this method to implement the functionality of an RMI client
//
}
