I tried my best to figure out a suitable solution, but it still doesn't pass !!! Please I need you help

Question about the task

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I don't know honesly what is messing. I tried with different approaches but none of them met the requirements. Could you help me

It's time to write the main method of the Handler class, which will call all
the helper methods we wrote earlier. Implement the void run() method in the Handler class.

It must:
1) Display a message indicating that a new connection was established with a remote
address that can be obtained using the getRemoteSocketAddress() method.
2) Create a Connection object using the socket field.
3) Call the method that implements the handshake with the client, and store the name of the new client.
4) Send the name of the new participant (USER_ADDED message) to all chat participants.
Think about which method is most suitable for this.
5) Inform the new participant about the existing participants.
6) Start the server's main message-processing loop.
7) Be sure that the connection is closed if an exception occurs.
8) If any IOExceptions or ClassNotFoundExceptions occur, catch them and display a message indicating
that an error occurred while communicating with the remote address. 9) After handling any exceptions, if step 11.3 has finished and returned a name, we need to remove
from connectionMap the entry for that name and send a USER_REMOVED message containing the name to all other participants.
10) The last thing we need to do in the run() method is display a message
indicating that the connection with the remote address is closed.

Our server is completely ready. Try running it.

Requirements:

The run() method should display a message indicating that a connection has been established with the remote address (use the getRemoteSocketAddress() method).
The run() method should create a new connection using the socket field as an argument.
The run() method should call the serverHandshake() method using the newly created connection as an argument; the return value will be the username (userName).
The run() method should call the sendBroadcastMessage() method using a new message as an argument (MessageType.USER_ADDED, userName).
The run() method should call the notifyUsers() method using connection and userName as arguments.
The run() method should call the serverMainLoop() method using connection and userName as arguments.
Before completing, the run() method must remove from connectionMap the entry that corresponds to userName, and send a message to all chat participants that the current user has been removed.
The run() method should correctly handle IOExceptions and ClassNotFoundExceptions.

package com.codegym.task.task30.task3008; import java.net.*; import java.util.Map; import java.io.*; import java.util.concurrent.ConcurrentHashMap; public class Server { private static Map<String, Connection> connectionMap = new ConcurrentHashMap<String, Connection>(); public static void sendBroadcastMessage(Message message) { for(Map.Entry<String, Connection> pair : connectionMap.entrySet()) { try { ((Connection) pair.getValue()).send(message); } catch(IOException e ) { ConsoleHelper.writeMessage("The message couldn't be sent "); } } } public static void main(String[] args){ ServerSocket serverSocket = null ; try{ int port = ConsoleHelper.readInt(); serverSocket = new ServerSocket(port); ConsoleHelper.writeMessage("The server is running "); while(true){ Socket socket = serverSocket.accept(); Handler handler = new Handler(socket); handler.start(); } } catch(Exception e){ try{ if( serverSocket != null) serverSocket.close(); } catch(IOException ex){ } ConsoleHelper.writeMessage(e.getMessage()); } } private static class Handler extends Thread { private final Socket socket ; public Handler(Socket socket) throws IOException { this.socket = socket; } @Override public void run(){ Connection connection = null ; String userName = null ; SocketAddress address = null; try { connection = new Connection(socket); address = connection.getRemoteSocketAddress(); ConsoleHelper.writeMessage("Connection established with the remote address :" +address.toString() ); } catch(IOException e1) { closeConnection(connection); } try { userName = serverHandshake(connection); } catch(IOException | ClassNotFoundException e2) { ConsoleHelper.writeMessage("An error occurred while communicating with the remote address." + address); closeConnection(connection); } try { sendBroadcastMessage(new Message(MessageType.USER_ADDED, "New user added")); notifyUsers(connection, userName); serverMainLoop(connection, userName); } catch(IOException | ClassNotFoundException e) { ConsoleHelper.writeMessage("An error occurred while communicating with the remote address." + address); closeConnection(connection); } finally { if(connectionMap.containsKey(userName)) { connectionMap.remove(userName); sendBroadcastMessage(new Message(MessageType.USER_REMOVED , userName)); } closeConnection(connection); } ConsoleHelper.writeMessage(" the connection with the remote address: " + address +" is closed" ); } private String serverHandshake(Connection connection) throws IOException,ClassNotFoundException{ while(true) { connection.send(new Message(MessageType.NAME_REQUEST,"Enter your username" )); Message response = connection.receive(); if(!isValidResponse(response)) continue; if(!isValidUsername(response.getData())) continue ; connectionMap.put(response.getData(), connection); connection.send(new Message(MessageType.NAME_ACCEPTED, "Request accepted")); return response.getData(); } } private void notifyUsers(Connection connection, String userName) throws IOException{ for(Map.Entry<String , Connection > pair : connectionMap.entrySet()){ if(pair.getKey().equals(userName)) continue; connection.send(new Message(MessageType.USER_ADDED, pair.getKey())); } } private void serverMainLoop(Connection connection, String userName) throws IOException, ClassNotFoundException{ Message messageReceived = null ; while(true) { if((messageReceived = connection.receive()).getType() == MessageType.TEXT) { Message messageToBeSent = new Message(MessageType.TEXT, userName + ": "+ messageReceived.getData()); sendBroadcastMessage(messageToBeSent); } else ConsoleHelper.writeMessage("message couldn't get sent"); } } private boolean isValidResponse(Message response) { return !(response == null || response.getType() != MessageType.USER_NAME ); } private boolean isValidUsername(String username) { return !(username.isEmpty() || connectionMap.containsKey(username)); } private void closeConnection(Connection connection) { if(connection != null) { try { connection.close(); } catch(IOException ex) { } } } } }

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Dave Andrea

Level 41 , Canada

18 September 2020, 14:45

Call getRemoteSocketAddress() on the socket field, not the connection. You can do that before creating the Connection object. Use a try with resources so the connection will auto close if there is an error. Put all your method calls (up to and including serverMainLoop) inside the same try block so you can catch all the exceptions in one shot instead of dealing with each one individually.