TCPServer.java

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

public class TCPServer {
	public static void main (String args[]) {
		int serverPort = 7896; // the server port
    	List <Connection> all_connections = new ArrayList<Connection>();
	   	try {
	        InetAddress addr = InetAddress.getLocalHost();
	    
	        // Get IP Address
	        byte[] ipAddr = addr.getAddress();
	    
	        // Get hostname
	        String hostname = addr.getHostName();
	        System.out.println("Server Name: " + hostname + "\nServer Port: " + serverPort);
	    }
	    catch (UnknownHostException e) {
	    }

		try{
			ServerSocket listenSocket = new ServerSocket(serverPort);
			System.out.println("Server is Ready");
			while(true) {
       			System.out.println("listening to client sockets");
				Socket clientSocket = listenSocket.accept();
        		System.out.println("connection found, creating a new connection thread");
				Connection c = new Connection(clientSocket);
        		all_connections.add(c);
        		c.all_connections = all_connections;
			}
		}
		catch(IOException e) {
			while (true)
				System.out.println("IOException Listen socket:"+e.getMessage());
		}
	}
}
class Connection extends Thread {
	ObjectInputStream in;
	ObjectOutputStream out;
	Socket clientSocket;
  	String name;
  	List <Connection> all_connections;
	public Connection (Socket aClientSocket) {
    	System.out.println("creating a new connection for client" );
		try {
			clientSocket = aClientSocket;
			out = new ObjectOutputStream(clientSocket.getOutputStream());
			in = new ObjectInputStream(clientSocket.getInputStream());
			this.start();
		} catch(IOException e) {System.out.println("Connection:"+e.getMessage());}
	}
	public void run(){
    	System.out.println("server thread started");
		boolean stop=false;
		while(stop==false)
		{
			try {			                 // an echo server

			// String data = in.readUTF();	                  // read a line of data from the stream
			// out.writeUTF(data);
      			formatted_msg msg = (formatted_msg) in.readObject();
      			if(msg.toString().equals("SETUP")){
      				//connect client to server
      				name = msg.dest;      				
      			}else if(msg.toString().equals("LOOPBACK")){
      				out.writeObject(msg);
      			}else if(msg.toString().equals("TERMINATE")){
      				try{
      					Thread.sleep(5000);
      				}catch(InterruptedException e){System.out.println("Error: InterruptedException");}
      				break;
      			}else if(msg.toString().equals("BROADCAST")){
      				for (Connection connection : all_connections) {
      					connection.out.writeObject(msg);
      				}
      			}else if(msg.toString().equals("NORMAL")){
      				String dest = msg.dest;
      				boolean found=false;
      				for(Connection connection : all_connections){
      					if(connection.name.equals(dest)){
      						connection.out.writeObject(msg);
      						found=true;
      					}
      				}
      				if(found==false){
      					out.writeObject("Error: No Clients Found");
      				}
      			}else if(msg.toString().equals("GET_ALL_CLIENTS")){
      				String clientList= "";
      				for(Connection connection: all_connections){
      					clientList+=connection.name+", ";
      				}
      				out.writeObject(clientList);
      			}

				System.out.println("Reply: " + msg);
      			out.writeObject(msg);  
      			System.out.println("num connection " + all_connections.size());
			}catch (EOFException e){System.out.println("EOF:"+e.getMessage());
			} catch(IOException e) {//System.out.println("readline:"+e.getMessage());
			} catch(ClassNotFoundException e) {System.out.println("readline:"+e.getMessage());
			}//catch (InterruptedException e){System.out.println("readline:"+e.getMessage());
			//} 
			finally{ 
				try {
      				clientSocket.close();
      				for (int i=0; i< all_connections.size(); i++) {
        				if (this == (Connection) all_connections.get(i)) {
          					System.out.println("Removing connection from the list, for " + name);
          					System.out.println("num connection upon removing " + all_connections.size());
          					all_connections.remove(i);
          					break;
        				}
      				}
    			}catch (IOException e){/*close failed*/}
    		}
		}
		

	}
}