Simple Chat Program

For my final project in networking I created a simple Server/Client Chat Program. This is the final version of the server side code.


//Necessary Libraries
import java.io.*;
import java.net.*;
import java.util.*;


//The Server Class contains all the classes and functions that
//this Chat Server needs to run
//Start this Class by calling the startHostingServer Function
class Server
{
    //Holds the Socket connections with the Clients
    private ArrayList connections;
    
    private ArrayList dirtyWords;
        
    //Class that will Handle the Client Connection
    //This is a thread to allow multiple clients to
    //be handled concurrently
    public class ClientHandler implements Runnable
    {
        //Buffered reader for input from the Client
        BufferedReader reader;
        
        //The socket connection to the Client
        Socket sock;
        
        //The Constructor that will be used when creating a instance
        //of this class.  It takes as a parameter the Socket that
        //has been set up with the Client
        public ClientHandler(Socket clientSocket)
        {
            try
            {
                //Sets up sock and reader
                sock = clientSocket;
                InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
                reader = new BufferedReader(isReader);
            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }
        }
        
        //This is what is run when the Thread is started
        //Gets any messages from the client and lets all the other clients
        //on this server know what the message is
        public void run()
        {
            String message;
            try
            {
                while((message = reader.readLine()) != null)
                {
                    tellEveryone(filterMessage(message));
                }
            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }
        }
    }
    
    //This is what is called to start the server
    //Creates a new StartServer and starts the getConnections
    //function
    //This is called by the StartHosting Class
    public void startHostingServer(int portNumber)
    {
        StartServer server = new StartServer();
        server.setupDirtyWords();
        server.getConnections(portNumber);
    }
    
    //This is the StartServer Class
    //This starts the server and gets connections to the clients
    public class StartServer
    {
        //This Sets up the dictionary that will be used to filter out
        //the dirty words that may be used
        public void setupDirtyWords()
        {
            dirtyWords = new ArrayList();
            try
            {
                //This is the file where the list of dirty words
                //are located at
                File dwFile = new File("dirtyWords.txt");
                FileReader fileReader = new FileReader(dwFile);
                BufferedReader bufReader = new BufferedReader(fileReader);
                
                String word;
                while((word = bufReader.readLine()) != null)
                {
                    dirtyWords.add(word + " ");
                }
                bufReader.close();
                
            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }
        }
        
        //Accepts Client Connections to the Server
        public void getConnections(int portNumber)
        {
            
            try
            {
                //Create the WelcomSocket for the Server to recieve Connections
                ServerSocket welcomeSocket;
                welcomeSocket = new ServerSocket(portNumber);
                
                //Initializes the connections ArrayList
                connections = new ArrayList();
            
                //This is continually run to continue accepting connections for
                //any host that may want to join
                while(true)
                {
                    Socket clientSocket = welcomeSocket.accept();
                    PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
                    connections.add(writer);
                    Thread t = new Thread(new ClientHandler(clientSocket));
                    t.start();
                }
            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }
        }
        
    }
    
    //send the message to everyone
    public void tellEveryone(String message)
    {
        Iterator it = connections.iterator();
        while(it.hasNext())
        {
            try
            {
                PrintWriter writer = (PrintWriter) it.next();
                writer.println(message);
                writer.flush();
            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }
        }
    }
    
    //This is the actual filtering of the message
    //This goes through the list of dirty words and makes sure
    //none of those words are present in the message
    public String filterMessage(String message)
    {
        for (int loop = 0; loop < dirtyWords.size(); loop++)
        {
            message = message.replaceAll(dirtyWords.get(loop).toString(), "*censored*");
        }
        return message;
    }
}


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