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package chat;
import javax.servlet.*;
import
javax.servlet.http.*;
import java.io.*;
import java.net.*;
import java.util.*;
import chat.*;
public class
ChatRoomServlet extends HttpServlet
{
public void doGet(HttpServletRequest req, HttpServletResponse
res)
throws IOException, ServletException
{
res.setContentType("text/html");
PrintWriter out = res.getWriter();
ChatRoom room = getRoom(req, res);
if (room == null)
{
return;
}
// Check if it's a request for a message list or a form
String listPar =
req.getParameter("list");
if (listPar != null
&& listPar.equals("true"))
{
writeMessages(out, room, getAvatarName(req));
}
else
{
writeForm(out);
}
out.close();
}
public void doPost(HttpServletRequest req, HttpServletResponse
res)
throws IOException, ServletException
{
res.setContentType("text/html");
PrintWriter out = res.getWriter();
ChatRoom room = getRoom(req, res);
if (room == null)
{
return;
}
String avatarName = getAvatarName(req);
// Save message if any
String msg = req.getParameter("msg");
if (msg != null && msg.length() != 0)
{
room.addChatEntry(new ChatEntry(avatarName, msg));
}
writeFrame(out, room);
out.close();
}
private String getAvatarName(HttpServletRequest req) {
HttpSession session = req.getSession();
String avatarName = (String)
session.getValue("avatarName");
if (avatarName == null)
{
// Entered a room for the first time?
avatarName = req.getParameter("avatarName");
if (avatarName ==
null || avatarName.length() == 0)
{
avatarName = "A spineless spy";
}
session.putValue("avatarName", avatarName);
}
else
{
// Entered a new room with a new name?
String newName =
req.getParameter("avatarName");
if (newName != null && newName.length() > 0
&&
!newName.equals(avatarName))
{
avatarName = newName;
session.putValue("avatarName", avatarName);
}
}
return avatarName;
}
private ChatRoom getRoom(HttpServletRequest req,
HttpServletResponse res)
throws IOException
{
HttpSession session = req.getSession();
PrintWriter out = res.getWriter();
String roomName = (String)
session.getValue("roomName");
if (roomName == null)
{
// Just entered?
roomName = req.getParameter("roomName");
if (roomName == null || roomName.length() == 0)
{
writeError(out, "Room not specified");
return null;
}
session.putValue("roomName", roomName);
}
else {
// Entered a new room?
String newRoom = req.getParameter("roomName");
if (newRoom != null && newRoom.length() > 0
&&
!newRoom.equals(roomName))
{
roomName = newRoom;
session.putValue("roomName", roomName);
}
}
RoomList roomList =
(RoomList) getServletContext().getAttribute("roomList");
ChatRoom room = roomList.getRoom(roomName);
if (room == null)
{
writeError(out, "Room " + roomName + "
not found");
return null;
}
return room;
}
private void writeError(PrintWriter out, String msg)
{
out.println("<HTML>");
out.println("<HEAD><TITLE>Error</TITLE></HEAD>");
out.println("<BODY>");
out.println("<H1>Error</H1>");
out.println(msg);
out.println("</BODY></HTML>");
}
private void writeForm(PrintWriter out)
{
out.println("<HTML>");
out.println("<BODY>");
out.println("<FORM METHOD=POST ACTION=chatRoom
TARGET=_top>");
// Add field for new message
out.println("<P>Enter your
message:<P>");
out.println("<TEXTAREA NAME=msg COLS=50 ROWS=3
WRAP=HARD>");
out.println("</TEXTAREA>");
// Add submit button and hidden field with room name
out.println("<P><INPUT TYPE=SUBMIT
VALUE='Send Message'>");
// Add an Exit button
out.println("</FORM>");
out.println("<FORM ACTION=listRooms METHOD=GET
TARGET=_top>");
out.println("<INPUT TYPE=SUBMIT
VALUE=Exit>");
out.println("</FORM>");
out.println("</BODY></HTML>");
}
private void writeFrame(PrintWriter out, ChatRoom room)
{
out.println("<HTML>");
out.println("<HEAD><TITLE>" +
room.getName() + "</TITLE></HEAD>");
out.println("<FRAMESET
ROWS='60%,30%' BORDER=0 FRAMEBORDER=NO>");
out.println("<FRAME
SRC=chatRoom?list=true NAME=list SCROLLING=AUTO>");
out.println("<FRAME SRC=chatRoom?list=false
NAME=form SCROLLING=AUTO>");
out.println("<NOFRAMES>");
out.println("<BODY>");
out.println("Viewing this page requires a browser
capable of displaying frames.");
out.println("</BODY>");
out.println("</NOFRAMES>");
out.println("</FRAMESET>");
out.println("</HTML>");
}
private void writeMessages(PrintWriter out, ChatRoom room,
String avatarName)
{
out.println("<HTML>");
out.println("<HEAD><META
http-equiv=\"refresh\"
content=\"5\"></HEAD>");
out.println("<BODY>");
out.println("<H1>You're in " +
room.getName() + " as " +
avatarName + "</H1>");
// List all messages in the room
Enumeration entries = room.getChatEntries();
if (!entries.hasMoreElements())
{
out.println("<FONT COLOR=RED>There are no
messages in this room yet</FONT>");
}
while (entries.hasMoreElements())
{
ChatEntry entry = (ChatEntry) entries.nextElement();
String entryName = entry.getAvatarName();
if (entryName.equals(avatarName))
{
out.print("<FONT COLOR=BLUE>");
}
out.println(entryName + " : " + entry.getChatMessage()
+
"<BR>");
if (entryName.equals(avatarName))
{
out.print("</FONT>");
}
}
out.println("</BODY></HTML>");
}
}
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