WebServer.java

/**
* A simple web server: it creates a new WebWorker for each new client
* connection, so all the WebServer object does is listen on the port
* for incoming client connection requests.
*
* This class contains the application "main()" (see below). At startup, 
* main() creates an object of this class (WebServer) and invokes its
* start() method. Since servers run continually, the start() method 
* never returns. It uses socket programming to listen for client network
* connection requests. When one happens, it creates a new object of
* the WebWorker class and hands that client connection off to the WebWorker
* object. The WebServer object then just keeps listening for new client
* connections. See the WebWorker source for more information about it.
* 
**/

import java.net.*;

public class WebServer
{

private ServerSocket socket;
private boolean running;

/**
* Constructor
**/
private WebServer()
{
   running = false;
}

/**
* Web server starting point. This method does not return until
* the server is finished, so perhaps it should be named "runServer"
* or something like that.
* @param port is the TCP port number to accept connections on
**/
private boolean start(int port)
{
   Socket workerSocket;
   WebWorker worker;
   try {
      socket = new ServerSocket(port);
   } catch (Exception e) {
      System.err.println("Error binding to port "+port+": "+e);
      return false;
   }
   while (true) {
      try {
         // wait and listen for new client connection
         workerSocket = socket.accept();
      } catch (Exception e) {
         System.err.println("No longer accepting: "+e);
         break;
      }
      // have new client connection, so fire off a worker on it
      worker = new WebWorker(workerSocket);
      new Thread(worker).start();
   }
   return true;
} // end start

/**
* Does not do anything, since start() never returns.
**/
private boolean stop()
{
   return true;
}

/**
* Application main: process command line and start web server; default
* port number is 8080 if not given on command line.
**/
public static void main(String args[])
{
   int port = 8080;
   if (args.length > 1) {
      System.err.println("Usage: java Webserver <portNumber>");
      return;
   } else if (args.length == 1) {
      try {
         port = Integer.parseInt(args[0]);
      } catch (Exception e) {
         System.err.println("Argument must be an int ("+e+")");
         return;
      }
   }
   WebServer server = new WebServer();
   if (!server.start(port)) {
      System.err.println("Execution failed!");
   }
} // end main

} // end class