ChatDispatchpublic class ChatDispatch extends HttpServlet
| Methods Summary |
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| public void | doGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)
res.setContentType("text/html");
if (!req.getParameterNames().hasMoreElements()) {
// There were no request parameters. Print a welcome page.
printWelcomePage(req, res);
}
else {
// There was at least one request parameter.
// Print a page containing the applet.
printAppletPage(req, res);
}
| | private void | printAppletPage(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)
PrintWriter out = res.getWriter();
out.println("<HTML>");
out.println("<HEAD><TITLE>An Absurdly Simple Chat</TITLE></HEAD>");
out.println("<BODY>");
out.println("<H1>An Absurdly Simple Chat</H1>");
String method = req.getParameter("method");
String user = req.getRemoteUser();
String applet = null;
if ("http".equals(method)) {
applet = "HttpChatApplet";
}
else if ("socket".equals(method)) {
applet = "SocketChatApplet";
}
else if ("rmi".equals(method)) {
applet = "RMIChatApplet";
}
else {
// No method given, or an invalid method given.
// Explain to the user what we expect.
out.println("Sorry, this servlet requires a <TT>method</TT> " +
"parameter with one of these values: " +
"http, socket, rmi");
return;
}
// Print the HTML code to generate the applet.
// Choose the applet code based on the method parameter.
// Provide a user parameter if we know the remote user.
out.println("<APPLET CODE=" + applet + " CODEBASE=/ " +
"WIDTH=500 HEIGHT=170>");
if (user != null)
out.println("<PARAM NAME=user VALUE=\"" + user + "\">");
out.println("</APPLET>");
out.println("</BODY></HTML>");
| | private void | printWelcomePage(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)
PrintWriter out = res.getWriter();
String me = req.getServletPath();
out.println("<HTML>");
out.println("<HEAD><TITLE>");
out.println("Welcome to an Absurdly Simple Chat");
out.println("</TITLE></HEAD>");
out.println();
out.println("<BODY>");
out.println("<H1>Welcome to an Absurdly Simple Chat</H1>");
out.println();
out.println("Would you like to communicate via:");
out.println("<UL>");
out.println(" <LI><A HREF=\"" + me + "?method=http\">http</A>");
out.println(" <LI><A HREF=\"" + me + "?method=socket\">socket</A>");
out.println(" <LI><A HREF=\"" + me + "?method=rmi\">rmi</A>");
out.println("</UL>");
out.println("</BODY></HTML>");
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