package coreservlets;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
/** Illustrates the value of persistent HTTP connections for
* pages that includes many images, applet classes, or
* other auxiliary content that would otherwise require
* a separate connection to retrieve.
*
* Taken from Core Servlets and JSP,
* http://www.apl.jhu.edu/~hall/csajsp/.
* 1999 Marty Hall; may be freely used or adapted.
*/
public class PersistentFrame extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
ByteArrayOutputStream byteStream =
new ByteArrayOutputStream(2056);
PrintWriter out = new PrintWriter(byteStream, true);
String persistenceFlag =
request.getParameter("usePersistence");
boolean usePersistence =
((persistenceFlag == null) ||
(!persistenceFlag.equals("no")));
String title;
if (usePersistence) {
title = "Using Persistent Connection";
} else {
title = "Not Using Persistent Connection";
}
out.println
("\n" +
"\n" +
"
" + title + "\n" +
"");
if (usePersistence) {
response.setContentLength(byteStream.size());
}
byteStream.writeTo(response.getOutputStream());
}
private String frameRow(int rowNum, boolean usePersistence) {
int cellNum = rowNum * 10;
String baseURL = "/servlet/coreservlets.FrameCell?cellNum=";
String persistenceFlag;
if (usePersistence)
persistenceFlag="";
else
persistenceFlag="&usePersistence=no";
String row =
" ";
return(row);
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}