import java.net.*; 
import java.io.*; 
import java.util.*;

public class BroadcastServer extends Thread
{ 
 protected static boolean serverContinue = true;
 protected Socket clientSocket;
 protected Shared outputStreamList;

 public static void main(String[] args) throws IOException 
   { 
    ServerSocket serverSocket = null; 
    Shared s = new Shared ();

    try { 
         serverSocket = new ServerSocket(10008); 
         System.out.println ("Connection Socket Created");
         try { 
              while (serverContinue)
                 {
                  serverSocket.setSoTimeout(10000);
                  //System.out.println ("Waiting for Connection");
                  try {
                       new BroadcastServer (serverSocket.accept(), s); 
                      }
                  catch (SocketTimeoutException ste)
                      {
                       //System.out.println ("Timeout Occurred");
                      }
                 }
             } 
         catch (IOException e) 
             { 
              System.err.println("Accept failed."); 
              System.exit(1); 
             } 
        } 
    catch (IOException e) 
        { 
         System.err.println("Could not listen on port: 10008."); 
         System.exit(1); 
        } 
    finally
        {
         try {
              System.out.println ("Closing Server Connection Socket");
              serverSocket.close(); 
             }
         catch (IOException e)
             { 
              System.err.println("Could not close port: 10008."); 
              System.exit(1); 
             } 
        }
   }

 private BroadcastServer (Socket clientSoc, Shared s)
   {
    clientSocket = clientSoc;
    outputStreamList = s;

    start();
   }

 public void run()
   {
    System.out.println ("New Communication Thread Started");

    try { 
         PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), 
                                      true); 
         outputStreamList.addStream (out);

         BufferedReader in = new BufferedReader( 
                 new InputStreamReader( clientSocket.getInputStream())); 

         String inputLine; 

         while ((inputLine = in.readLine()) != null) 
             { 
              System.out.println ("Server: " + inputLine); 

              if (inputLine.equals("?")) 
                  inputLine = new String ("\"Bye.\" ends Client, " +
                      "\"End Server.\" ends Server");

              out.println(inputLine); 
              outputStreamList.sendMessageToStreams(inputLine);

              if (inputLine.equals("Bye.")) 
                  break; 

              if (inputLine.equals("End Server.")) 
                  serverContinue = false; 
             } 

         // remove the stream from the shared data
         outputStreamList.removeStream (out);

         out.close(); 
         in.close(); 
         clientSocket.close(); 
        } 
    catch (IOException e) 
        { 
         System.err.println("Problem with Communication Server");
         System.exit(1); 
        } 
    }
} 

class Shared
{
   private Vector<PrintWriter> outputStreamList;

   public Shared()
   {
      outputStreamList = new Vector();
   }

   synchronized void addStream (PrintWriter outStream)
   {
      if (!(outputStreamList.contains(outStream))) 
        {
         outputStreamList.addElement(outStream);
         System.out.println("Registered new client ");
        } // end if

   }

   synchronized  void sendMessageToStreams (String s)
   {
      // Loop for streams in the vector and write s to each stream
    System.out.println( "**************************************\n"
        + "Broadcast initiated ---");

    for (int i = 0; i < outputStreamList.size(); i++){
      System.out.println("doing "+ i +"-th callback\n");    
      // convert the vector object to a callback object
      PrintWriter outStream = (PrintWriter)outputStreamList.elementAt(i);
      // invoke the callback method
      outStream.println(s);
    }// end for

    System.out.println("********************************\n" +
                       "Server completed Broadcast ---");
   }

   synchronized void removeStream (PrintWriter outStream)
   {
      // remove the stream from the vector
    if (outputStreamList.removeElement(outStream)) 
      {
       System.out.println("Unregistered client ");
      } 
    else 
      {
       System.out.println("Unregister: client wasn't registered.");
      }
   }
}