Client.java

/**
 * Client.java
 *
 * This class is used to represent the players at the blackjack table. It allows them to enter their username,
 * as well as send and receive messages.
 *
 */

// Import necessary libraries
import java.io.*;
import java.net.Socket;
import java.util.Scanner;

public class Client {
    // Initialize variables needed for clients to identify themselves and interact with others.
    private Socket socket;
    private BufferedReader bufferedReader;
    private BufferedWriter bufferedWriter;
    private String username;

    // Client constructor
    public Client(Socket socket, String username){
        try{
            // Initialize all the attribute variables to the appropriate values.
            this.socket = socket;
            this.bufferedWriter = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
            this.bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            this.username = username;
        }catch (IOException e){
            closeEverything(socket, bufferedReader, bufferedWriter);
        }
    }

    // Function used to allow this client to send messages to other clients and the server
    // Print out who said what to every client
    public void sendMessage(){
        try{
            bufferedWriter.write(username);
            bufferedWriter.newLine();
            bufferedWriter.flush();

            Scanner scanner = new Scanner(System.in);
            while(socket.isConnected()){
                String messageToSend = scanner.nextLine();
                bufferedWriter.write(username + ": " + messageToSend);
                bufferedWriter.newLine();
                bufferedWriter.flush();
            }
        }catch(IOException e){
            closeEverything(socket, bufferedReader, bufferedWriter);
        }
    }

    // Function used to have the client constantly listen for a message so that
    // in case a message is sent out from another client or a server, this client
    // doesn't miss it and is able to read it and print it out
    public void listenForMessage(){
        new Thread(new Runnable(){
            @Override
            public void run(){
                String msgFromGroupChat;

                while(socket.isConnected()){
                    try{
                        msgFromGroupChat = bufferedReader.readLine();
                        System.out.println(msgFromGroupChat);
                    }catch(IOException e){
                        closeEverything(socket, bufferedReader, bufferedWriter);
                    }
                }
            }
        }).start();
    }

    // Function used to close every open attribute of the client when they disconnect
    public void closeEverything(Socket socket, BufferedReader bufferedReader, BufferedWriter bufferedWriter){
        try{
            if(bufferedReader != null){
                bufferedReader.close();
            }
            if(bufferedWriter != null){
                bufferedWriter.close();
            }
            if(socket != null){
                socket.close();
            }
        }catch (IOException e){
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {

        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter your name for the game: ");
        String username = scanner.nextLine();
        Socket socket = new Socket("localhost", 1234);
        Client client = new Client(socket, username);
        client.listenForMessage();
        client.sendMessage();

    }

}