fixed #49

clean up

client/src/main/java/ch/zhaw/pm2/multichat/client/ChatWindowController.java

@@ -1,7 +1,9 @@
 package ch.zhaw.pm2.multichat.client;
 
+import ch.zhaw.pm2.multichat.protocol.ConnectionHandler;
 import ch.zhaw.pm2.multichat.protocol.ConnectionHandler.State;
 import ch.zhaw.pm2.multichat.protocol.ChatProtocolException;
+import ch.zhaw.pm2.multichat.protocol.Message;
 import javafx.application.Platform;
 import javafx.beans.value.ChangeListener;
 import javafx.beans.value.ObservableValue;
@@ -17,28 +19,51 @@ import java.io.IOException;
 
 import static ch.zhaw.pm2.multichat.protocol.ConnectionHandler.State.*;
 
+/**
+ * Class Representing the Controller Element of the Window, also Contains the Elements that contacts the View Elements via
+ * Listeners and Observable Objects.
+ * To Contact the Model Elements needed it also holds references to message and the Connectionhandler.
+ */
 public class ChatWindowController {
     private ClientConnectionHandler connectionHandler;
     private ClientMessageList messages;
-
     private final WindowCloseHandler windowCloseHandler = new WindowCloseHandler();
 
-    @FXML private Pane rootPane;
-    @FXML private TextField serverAddressField;
-    @FXML private TextField serverPortField;
-    @FXML private TextField userNameField;
-    @FXML private TextField messageField;
-    @FXML private TextArea messageArea;
-    @FXML private Button connectButton;
-    @FXML private Button sendButton;
-    @FXML private TextField filterValue;
+    @FXML
+    private Pane rootPane;
+    @FXML
+    private TextField serverAddressField;
+    @FXML
+    private TextField serverPortField;
+    @FXML
+    private TextField userNameField;
+    @FXML
+    private TextField messageField;
+    @FXML
+    private TextArea messageArea;
+    @FXML
+    private Button connectButton;
+    @FXML
+    private TextField filterValue;
+    @FXML
+    private Button sendButton;
 
 
+    /**
+     * Takes a message object and stores it used as Model and also starts message Listener via messageListener method.
+     *
+     * @param messages Object that will be set for use as Model
+     */
     public void setMessages(ClientMessageList messages) {
         this.messages = messages;
         messageListener();
     }
 
+    /**
+     * Takes a Connection handler object and stores it used as Model and also starts a Listener for it.
+     *
+     * @param connectionHandler that will be set and used as Model.
+     */
     public void setConnectionHandler(ClientConnectionHandler connectionHandler) {
         this.connectionHandler = connectionHandler;
         startConnectionHandlerListener();
@@ -46,10 +71,17 @@ public class ChatWindowController {
         serverPortField.setText(String.valueOf(connectionHandler.getServerPortProperty().get()));
     }
 
+    /**
+     * Method which closes the Application via use of the disconnect Method.
+     */
     private void applicationClose() {
         disconnect();
     }
 
+    /**
+     * Method that handles the Connect Button and Initiates connect when connectionHandler is not Connected or
+     * a disconnect when it is connected.
+     */
     @FXML
     private void toggleConnection() {
         if (connectionHandler == null || connectionHandler.getStateProperty().get() != CONNECTED) {
@@ -59,16 +91,22 @@ public class ChatWindowController {
         }
     }
 
+    /**
+     * Initiates a connection by starting Connection Handler and telling, the Handler to start a connection.
+     */
     private void connect() {
         try {
             messages.clear(); // clear message list
             startConnectionHandler();
             connectionHandler.connect();
         } catch (ChatProtocolException | IOException e) {
-            addError(e.getMessage());
+            addError("Error while starting Connection Handler and connect" + e);
         }
     }
 
+    /**
+     * Initiates disconnecting of the connectionHandler, also checks if connectionHandler is available.
+     */
     private void disconnect() {
         if (connectionHandler == null) {
             addError("No connection handler");
@@ -81,6 +119,9 @@ public class ChatWindowController {
         }
     }
 
+    /**
+     * Method which is used when the send button is pressed and handing over a message to the Connection Handler
+     */
     @FXML
     private void message() {
         String messageString = messageField.getText().strip();
@@ -97,11 +138,20 @@ public class ChatWindowController {
         }
     }
 
+    /**
+     * Method which is used when a Filter is applied
+     * Setting the Text in the message area after sending it through the filter.
+     */
     @FXML
     private void applyFilter() {
         Platform.runLater(() -> this.messageArea.setText(messages.getFilteredMessages(filterValue.getText().strip())));
     }
 
+    /**
+     * Starts the ConnectionHandler setting the username and Checking if the name follows the valid format of no spaces.
+     *
+     * @throws IOException for error that may occur during initialization of connectionHandler.
+     */
     private void startConnectionHandler() throws IOException {
         String userName = userNameField.getText();
         if (!userName.contains(" ")) {
@@ -110,16 +160,18 @@ public class ChatWindowController {
             connectionHandler.initialize(serverAddress, serverPort, userName);
             new Thread(connectionHandler).start();
 
-            //register Listener
-            //startConnectionHandlerListener();
-
-            // register window close handler
             rootPane.getScene().getWindow().addEventHandler(WindowEvent.WINDOW_CLOSE_REQUEST, windowCloseHandler);
         } else {
             addError("It is not allowed to have spaces in username!");
         }
     }
 
+    /**
+     * Sets the state shown according to the state the method receives, if state indicates disconnected it will also inform the
+     * Connection Handler and tell it to stop Receiving more messages.
+     *
+     * @param newState is the state that it should be set to.
+     */
     public void stateChanged(State newState) {
         // update UI (need to be run in UI thread: see Platform.runLater())
         Platform.runLater(new Runnable() {
@@ -133,6 +185,11 @@ public class ChatWindowController {
         }
     }
 
+    /**
+     * Sets displayed username according to the String provided.
+     *
+     * @param userName provided String that is set as name.
+     */
     public void setUserName(String userName) {
         Platform.runLater(new Runnable() {
             @Override
@@ -142,6 +199,11 @@ public class ChatWindowController {
         });
     }
 
+    /**
+     * Sets displayed Server Address.
+     *
+     * @param serverAddress provided String that is set as server address.
+     */
     public void setServerAddress(String serverAddress) {
         Platform.runLater(new Runnable() {
             @Override
@@ -151,6 +213,11 @@ public class ChatWindowController {
         });
     }
 
+    /**
+     * Sets displayed Server port.
+     *
+     * @param serverPort provided String that is set as server port.
+     */
     public void setServerPort(int serverPort) {
         Platform.runLater(new Runnable() {
             @Override
@@ -160,16 +227,31 @@ public class ChatWindowController {
         });
     }
 
+    /**
+     * Method which adds an incoming String as an Error Message.
+     *
+     * @param message String to be added as Error
+     */
     public void addError(String message) {
-        messages.addMessage(new Message(Message.MessageType.ERROR, null, null, message));
+        messages.addMessage(new Message(ConnectionHandler.DATA_TYPE.DATA_TYPE_ERROR, null, null, message));
     }
 
+    /**
+     * Nested Class in charge of Closing the window
+     */
     class WindowCloseHandler implements EventHandler<WindowEvent> {
+
+        /**
+         * @param event the event which occurred when Windows is closed
+         */
         public void handle(WindowEvent event) {
             applicationClose();
         }
     }
 
+    /**
+     * Starts several new Listener for Connection Handler changes by using several observable properties.
+     */
     public void startConnectionHandlerListener() {
         connectionHandler.getStateProperty().addListener(new ChangeListener<State>() {
             @Override
@@ -200,6 +282,9 @@ public class ChatWindowController {
         });
     }
 
+    /**
+     * Starts a new Listener for messages by using the observable Boolean.
+     */
     private void messageListener() {
         messages.getChangedProperty().addListener(new ChangeListener<Boolean>() {
             @Override

client/src/main/java/ch/zhaw/pm2/multichat/client/Client.java

@@ -2,8 +2,16 @@ package ch.zhaw.pm2.multichat.client;
 
 import javafx.application.Application;
 
+/**
+ * Client Main Class in charge of starting the UI only contains main method.
+ */
 public class Client {
 
+    /**
+     * Main method which launches the Client UI
+     *
+     * @param args no arguments needed
+     */
     public static void main(String[] args) {
         // Start UI
         System.out.println("Starting Client Application");

client/src/main/java/ch/zhaw/pm2/multichat/client/ClientConnectionHandler.java

@@ -2,6 +2,7 @@ package ch.zhaw.pm2.multichat.client;
 
 import ch.zhaw.pm2.multichat.protocol.ChatProtocolException;
 import ch.zhaw.pm2.multichat.protocol.ConnectionHandler;
+import ch.zhaw.pm2.multichat.protocol.Message;
 import ch.zhaw.pm2.multichat.protocol.NetworkHandler;
 import javafx.beans.property.SimpleIntegerProperty;
 import javafx.beans.property.SimpleObjectProperty;
@@ -13,18 +14,29 @@ import java.net.SocketException;
 import java.util.Scanner;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+
 import static ch.zhaw.pm2.multichat.protocol.ConnectionHandler.State.*;
 
+/**
+ * Client Connection Handler Class is used for the connection of the Client to a server
+ * it is used part as a Model storing properties like userName, state, serverAddress and Port.
+ * Also holds methods to
+ */
 public class ClientConnectionHandler extends ConnectionHandler implements Runnable {
 
     private final Pattern messagePattern = Pattern.compile("^(?:@(\\S*))?\\s*(.*)$");
 
-    private SimpleStringProperty userName;
-    private SimpleObjectProperty<State> state;
-    private ClientMessageList messages;
-    private SimpleStringProperty serverAddress;
-    private SimpleIntegerProperty serverPort;
+    private final SimpleStringProperty userName;
+    private final SimpleObjectProperty<State> state;
+    private final ClientMessageList messages;
+    private final SimpleStringProperty serverAddress;
+    private final SimpleIntegerProperty serverPort;
 
+    /**
+     * Constructor initializes ConnectionHandler by Setting default values for the fields and stores the given messages itself.
+     *
+     * @param messages
+     */
     public ClientConnectionHandler(ClientMessageList messages) {
         super();
         this.messages = messages;
@@ -34,6 +46,14 @@ public class ClientConnectionHandler extends ConnectionHandler implements Runnab
         this.userName = new SimpleStringProperty(null);
     }
 
+    /**
+     * Called to initialize the ClientConnectionHandler when trying to start a connection
+     *
+     * @param serverAddress to connect to
+     * @param serverPort    to connect to
+     * @param userName      to connect as
+     * @throws IOException if connection to Server not possible
+     */
     public void initialize(String serverAddress, int serverPort, String userName) throws IOException {
         state.set(NEW);
         this.serverAddress.set(serverAddress);
@@ -42,33 +62,71 @@ public class ClientConnectionHandler extends ConnectionHandler implements Runnab
         this.userName.set((userName == null || userName.isBlank()) ? USER_NONE : userName);
     }
 
-    public SimpleStringProperty getServerAddressProperty() { return serverAddress; }
+    /**
+     * Observable getter Method for the stored serverAddress
+     *
+     * @return the stored serverAddress
+     */
+    public SimpleStringProperty getServerAddressProperty() {
+        return serverAddress;
+    }
 
-    public SimpleIntegerProperty getServerPortProperty() { return serverPort; }
+    /**
+     * Observable getter Method for the stored serverPort
+     *
+     * @return the stored serverPort
+     */
+    public SimpleIntegerProperty getServerPortProperty() {
+        return serverPort;
+    }
 
+    /**
+     * Observable getter Method for the stored state
+     *
+     * @return the stored state
+     */
     public SimpleObjectProperty<State> getStateProperty() {
         return this.state;
     }
 
-    public SimpleStringProperty getUserNameProperty() { return userName; }
+    /**
+     * Observable getter Method for the stored userName
+     *
+     * @return the stored userName
+     */
+    public SimpleStringProperty getUserNameProperty() {
+        return userName;
+    }
 
+    /**
+     * Method which sets a new State.
+     *
+     * @param newState the state that will be set
+     */
     public void setState(State newState) {
         state.set(newState);
     }
 
+    /**
+     * Standard run method which will directly start the startReceiving method.
+     */
     public void run() {
         startReceiving();
     }
 
+    /**
+     * Method that is started by the run method, starts a connection handler.
+     * Figures out if connection is available if not determines the error cause and gives an error accordingly.
+     */
     private void startReceiving() {
         System.out.println("Starting Connection Handler");
         try {
             System.out.println("Start receiving data...");
             while (getConnection().isAvailable()) {
-                String data = getConnection().receive();
+                Message data = getConnection().receive();
                 processData(data);
             }
-            System.out.println("Stopped recieving data");
+            System.out.println("Stopped receiving data");
         } catch (SocketException e) {
             System.out.println("Connection terminated locally");
             this.setState(DISCONNECTED);
@@ -85,6 +143,9 @@ public class ClientConnectionHandler extends ConnectionHandler implements Runnab
         System.out.println("Stopped Connection Handler");
     }
 
+    /**
+     * Method which is used to stop receiving data, gets the current connection and closes it.
+     */
     public void stopReceiving() {
         System.out.println("Closing Connection Handler to Server");
         try {
@@ -97,88 +158,114 @@ public class ClientConnectionHandler extends ConnectionHandler implements Runnab
         System.out.println("Closed Connection Handler to Server");
     }
 
-    private void processData(String data) {
-        try {
-            Scanner scanner = new Scanner(data);
-            StringBuilder sender = new StringBuilder();
-            StringBuilder reciever = new StringBuilder();
-            StringBuilder type = new StringBuilder();
-            StringBuilder payload = new StringBuilder();
-            super.processData(scanner,sender,reciever,type,payload);
-
+    /**
+     * Method which processes data and determines its type then uses the corresponding method to process it.
+     *
+     * @param data that is received in a form of a String and then used depending on its determined cause.
+     */
+    private void processData(Message data) {
         // dispatch operation based on type parameter
-            if (type.toString().equals(getDataTypeConnect())) {
+        if (data.getType() == DATA_TYPE.DATA_TYPE_CONNECT) {
             System.err.println("Illegal connect request from server");
-            } else if (type.toString().equals(getDataTypeConfirm())) {
-                caseConfirm(sender.toString(), reciever.toString(), payload.toString());
-            } else if (type.toString().equals(getDataTypeDisconnect())) {
-                caseDisconnect(sender.toString(),reciever.toString(),payload.toString());
-            } else if (type.toString().equals(getDataTypeMessage())) {
-                caseMessage(sender.toString(),reciever.toString(),payload.toString());
-            } else if (type.toString().equals(getDataTypeError())) {
-                caseError(sender.toString(), reciever.toString(), payload.toString());
+        } else if (data.getType() == DATA_TYPE.DATA_TYPE_CONFIRM) {
+            caseConfirm(data);
+        } else if (data.getType() == DATA_TYPE.DATA_TYPE_DISCONNECT) {
+            caseDisconnect(data);
+        } else if (data.getType() == DATA_TYPE.DATA_TYPE_MESSAGE) {
+            caseMessage(data);
+        } else if (data.getType() == DATA_TYPE.DATA_TYPE_ERROR) {
+            caseError(data);
         } else {
-                System.out.println("Unknown data type received: " + type);
-            }
-        } catch (ChatProtocolException e) {
-            System.err.println("Error while processing data: " + e.getMessage());
-            sendData(USER_NONE, userName.get(), getDataTypeError(), e.getMessage());
+            System.out.println("Unknown data type received: " + data.getType());
         }
     }
 
-    private void caseConfirm(String sender, String reciever, String payload) {
+    private void caseConfirm(Message data) {
         if (state.get() == CONFIRM_CONNECT) {
-            this.userName.set(reciever);
+            this.userName.set(data.getReceiver());
             this.serverPort.set(getConnection().getRemotePort());
             this.serverAddress.set(getConnection().getRemoteHost());
-            messages.addMessage(new Message(Message.MessageType.INFO,sender,reciever,payload));
-            System.out.println("CONFIRM: " + payload);
+            messages.addMessage(data);
+            System.out.println("CONFIRM: " + data.getText());
             this.setState(CONNECTED);
         } else if (state.get() == CONFIRM_DISCONNECT) {
-            messages.addMessage(new Message(Message.MessageType.INFO,sender,reciever,payload));
-            System.out.println("CONFIRM: " + payload);
+            messages.addMessage(data);
+            System.out.println("CONFIRM: " + data.getText());
             this.setState(DISCONNECTED);
         } else {
-            System.err.println("Got unexpected confirm message: " + payload);
+            System.err.println("Got unexpected confirm message: " + data.getText());
         }
     }
 
-    private void caseDisconnect(String sender, String reciever, String payload) {
+    /**
+     * Initiates the disconnect sequence and sends the message with all its info.
+     *
+     * @param data Data which has been transmitted
+     */
+    private void caseDisconnect(Message data) {
         if (state.get() == DISCONNECTED) {
-            System.out.println("DISCONNECT: Already in disconnected: " + payload);
+            System.out.println("DISCONNECT: Already in disconnected: " + data.getText());
             return;
         }
-        messages.addMessage(new Message(Message.MessageType.INFO,sender,reciever,payload));
-        System.out.println("DISCONNECT: " + payload);
+        messages.addMessage(data);
+        System.out.println("DISCONNECT: " + data.getText());
         this.setState(DISCONNECTED);
     }
 
-    private void caseMessage(String sender, String reciever, String payload) {
+    /**
+     * Initiates the procedure to send a new message and sends one as such.
+     *
+     * @param data Data which has been transmitted
+     */
+    private void caseMessage(Message data) {
         if (state.get() != CONNECTED) {
-            System.out.println("MESSAGE: Illegal state " + state + " for message: " + payload);
+            System.out.println("MESSAGE: Illegal state " + state + " for message: " + data.getText());
             return;
         }
-        messages.addMessage(new Message(Message.MessageType.MESSAGE,sender,reciever,payload));
-        System.out.println("MESSAGE: From " + sender + " to " + reciever + ": "+  payload);
+        messages.addMessage(data);
+        System.out.println("MESSAGE: From " + data.getSender() + " to " + data.getReceiver() + ": " + data.getText());
     }
 
-    private void caseError(String sender, String reciever, String payload) {
-        messages.addMessage(new Message(Message.MessageType.ERROR,sender,reciever,payload));
-        System.out.println("ERROR: " + payload);
+    /**
+     * Stores the message as an error message and displays it as such as well.
+     *
+     * @param data Data which has been transmitted
+     */
+    private void caseError(Message data) {
+        messages.addMessage(data);
+        System.out.println("ERROR: " + data.getText());
     }
 
+    /**
+     * Send connect attempt to Server
+     *
+     * @throws ChatProtocolException Error that is thrown if the state is not set to NEW
+     */
     public void connect() throws ChatProtocolException {
         if (state.get() != NEW) throw new ChatProtocolException("Illegal state for connect: " + state);
         this.sendData(userName.get(), USER_NONE, getDataTypeConnect(), null);
         this.setState(CONFIRM_CONNECT);
     }
 
+    /**
+     * Send Disconnect attempt to server
+     *
+     * @throws ChatProtocolException Error tha si thrown if state is invalid
+     */
     public void disconnect() throws ChatProtocolException {
-        if (state.get() != NEW && state.get() != CONNECTED) throw new ChatProtocolException("Illegal state for disconnect: " + state);
+        if (state.get() != NEW && state.get() != CONNECTED)
+            throw new ChatProtocolException("Illegal state for disconnect: " + state);
         this.sendData(userName.get(), USER_NONE, getDataTypeDisconnect(), null);
         this.setState(CONFIRM_DISCONNECT);
     }
 
+    /**
+     * Sends message to Server
+     *
+     * @param messageString The message the user wants to send
+     * @return true if message is valid else false
+     * @throws ChatProtocolException if illegal connection state
+     */
     public boolean message(String messageString) throws ChatProtocolException {
         if (state.get() != CONNECTED) throw new ChatProtocolException("Illegal state for message: " + state);
 

client/src/main/java/ch/zhaw/pm2/multichat/client/ClientMessageList.java

@@ -1,29 +1,46 @@
 package ch.zhaw.pm2.multichat.client;
 
+import ch.zhaw.pm2.multichat.protocol.ConnectionHandler;
+import ch.zhaw.pm2.multichat.protocol.Message;
 import javafx.beans.property.SimpleBooleanProperty;
 
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Class that is used to store the messages in an ArrayList
+ * And also as a Model that informs the controller via Listeners that can be initialized
+ */
 public class ClientMessageList {
     private List<Message> messages = new ArrayList<>();
-    private SimpleBooleanProperty changed = new SimpleBooleanProperty(false);
+    private final SimpleBooleanProperty changed = new SimpleBooleanProperty(false);
 
+    /**
+     * Adds a new message to ArrayList and also informs Listener.
+     *
+     * @param message that should be added
+     */
     public void addMessage(Message message) {
         messages.add(message);
         changed.set(!changed.get());
     }
 
+    /**
+     * Applies a given filter over all messages and returns the result as a new String.
+     * Method is also in charge of applying the correct prefix to the message according to its type.
+     *
+     * @param filter is the applied filter on all the messages that are stored.
+     * @return String that matches the given filter.
+     */
     public String getFilteredMessages(String filter) {
         StringBuilder result = new StringBuilder();
         boolean showAll = filter == null || filter.isBlank();
         for (Message message : messages) {
-			if(showAll || message.matchesFilter(filter))
-			{
+            if (showAll || message.matchesFilter(filter)) {
                 switch (message.getType()) {
-                    case MESSAGE -> result.append(String.format("[%s -> %s] %s\n", message.getSender(), message.getReceiver(), message.getText()));
-                    case ERROR -> result.append(String.format("[ERROR] %s\n", message.getText()));
-                    case INFO -> result.append(String.format("[INFO] %s\n", message.getText()));
+                    case DATA_TYPE_MESSAGE -> result.append(String.format("[%s -> %s] %s\n", message.getSender(), message.getReceiver(), message.getText()));
+                    case DATA_TYPE_ERROR -> result.append(String.format("[ERROR] %s\n", message.getText()));
+                    case DATA_TYPE_CONFIRM, DATA_TYPE_DISCONNECT, DATA_TYPE_CONNECT -> result.append(String.format("[INFO] %s\n", message.getText()));
                     default -> result.append(String.format("[ERROR] %s\n", "Unexpected message type: " + message.getType()));
                 }
             }
@@ -31,11 +48,21 @@ public class ClientMessageList {
         return result.toString();
     }
 
+    /**
+     * Overwrites the Arraylist of messages, clearing it, also informs all Listeners.
+     */
     public void clear() {
         messages = new ArrayList<>();
         changed.set(!changed.get());
     }
 
-    public SimpleBooleanProperty getChangedProperty() { return changed; }
+    /**
+     * Getter Method to check the current value of SimpleBooleanProperty changed.
+     *
+     * @return the current value of changed
+     */
+    public SimpleBooleanProperty getChangedProperty() {
+        return changed;
+    }
 
 }

client/src/main/java/ch/zhaw/pm2/multichat/client/ClientUI.java

@@ -6,15 +6,32 @@ import javafx.scene.Scene;
 import javafx.scene.layout.Pane;
 import javafx.stage.Stage;
 
+/**
+ * Class in charge of initializing and loading elements needed for the GUI.
+ * Also Launching the chat window with pre-given parameters
+ */
 public class ClientUI extends Application {
-    private ClientMessageList clientMessageList = new ClientMessageList();
-    private ClientConnectionHandler connectionHandler = new ClientConnectionHandler(clientMessageList);
+    private final ClientMessageList clientMessageList = new ClientMessageList();
+    private final ClientConnectionHandler connectionHandler = new ClientConnectionHandler(clientMessageList);
 
+    /**
+     * Start method will only run the chatWindow method.
+     *
+     * @param primaryStage the primary stage for this application, onto which
+     *                     the application scene can be set.
+     *                     Applications may create other stages, if needed, but they will not be
+     *                     primary stages.
+     */
     @Override
     public void start(Stage primaryStage) {
         chatWindow(primaryStage);
     }
 
+    /**
+     * Method is in charge of loading the FXML file and then initializing the controllers and setting some parameters for the stage.
+     *
+     * @param primaryStage of the Application onto which the Scene is set.
+     */
     private void chatWindow(Stage primaryStage) {
         try {
             FXMLLoader loader = new FXMLLoader(getClass().getResource("ChatWindow.fxml"));

client/src/main/java/ch/zhaw/pm2/multichat/client/Message.java

@@ -1,71 +0,0 @@
-package ch.zhaw.pm2.multichat.client;
-
-/**
-A Message object represents one Message of a client. Can be stored in ClientMessageList.
- */
-public class Message {
-    private MessageType type;
-    private String sender;
-    private String receiver;
-    private String text;
-
-    /**
-     * Constructor of Message. Needs all Information about a Message to save them.
-     * @param type Message (if it's a message typed by a user), Error or Information (if it is generated automatically, in this case sender and reciever will be null)
-     * @param sender The User who has sent the message.
-     * @param receiver The User who should recieve the message.
-     * @param text The Text of the message.
-     */
-    public Message(MessageType type, String sender, String receiver, String text) {
-        this.type = type;
-        this.sender = sender;
-        this.receiver = receiver;
-        this.text = text;
-    }
-
-    /**
-     * Checks if the Filter String is contained in one of the datafields sender, receiver or text
-     * @param filter The Filter String
-     * @return true if it the Filter String is contained in a datafield.
-     */
-    public boolean matchesFilter(String filter){
-        return (sender != null && sender.contains(filter)) ||
-            (receiver != null && receiver.contains(filter)) ||
-            (text != null && text.contains(filter));
-    }
-
-    /**
-     * @return The type of the message.
-     */
-    public MessageType getType() {
-        return type;
-    }
-
-    /**
-     * @return The User who has sent the Message.
-     */
-    public String getSender() {
-        return sender;
-    }
-
-    /**
-     * @return The Reciever who recieves the Message.
-     */
-    public String getReceiver() {
-        return receiver;
-    }
-
-    /**
-     * @return The Text of the Message.
-     */
-    public String getText() {
-        return text;
-    }
-
-    /**
-     * Enummeration of Message Types.
-     */
-    public enum MessageType {
-        INFO, MESSAGE, ERROR;
-    }
-}

client/src/main/resources/ch/zhaw/pm2/multichat/client/ChatWindow.fxml

@@ -12,7 +12,9 @@
 <?import javafx.scene.layout.HBox?>
 <?import javafx.scene.layout.VBox?>
 
-<BorderPane fx:id="rootPane" minWidth="-Infinity" prefHeight="500.0" prefWidth="420.0" xmlns="http://javafx.com/javafx/18" xmlns:fx="http://javafx.com/fxml/1" fx:controller="ch.zhaw.pm2.multichat.client.ChatWindowController">
+<BorderPane xmlns:fx="http://javafx.com/fxml/1" fx:id="rootPane" minWidth="-Infinity" prefHeight="500.0"
+            prefWidth="420.0" xmlns="http://javafx.com/javafx/18"
+            fx:controller="ch.zhaw.pm2.multichat.client.ChatWindowController">
     <top>
         <VBox BorderPane.alignment="CENTER">
             <children>
@@ -31,20 +33,25 @@
                 </MenuBar>
                 <HBox fillHeight="false" spacing="5.0">
                     <children>
-	            <TextField fx:id="userNameField" alignment="CENTER_RIGHT" maxWidth="1.7976931348623157E308" minWidth="110.0" promptText="Username" HBox.hgrow="SOMETIMES" />
-	            <Label alignment="CENTER" contentDisplay="CENTER" text="\@" textAlignment="CENTER" textOverrun="CLIP" HBox.hgrow="NEVER">
+                        <TextField fx:id="userNameField" alignment="CENTER_RIGHT" maxWidth="1.7976931348623157E308"
+                                   minWidth="110.0" promptText="Username" HBox.hgrow="SOMETIMES"/>
+                        <Label alignment="CENTER" contentDisplay="CENTER" text="\@" textAlignment="CENTER"
+                               textOverrun="CLIP" HBox.hgrow="NEVER">
                             <HBox.margin>
                                 <Insets bottom="5.0" top="5.0"/>
                             </HBox.margin>
                         </Label>
-	            <TextField fx:id="serverAddressField" alignment="CENTER_RIGHT" minWidth="110.0" promptText="Host" HBox.hgrow="SOMETIMES" />
+                        <TextField fx:id="serverAddressField" alignment="CENTER_RIGHT" minWidth="110.0"
+                                   promptText="Host" HBox.hgrow="SOMETIMES"/>
                         <Label text=":" HBox.hgrow="NEVER">
                             <HBox.margin>
                                 <Insets bottom="5.0" top="5.0"/>
                             </HBox.margin>
                         </Label>
-	            <TextField fx:id="serverPortField" minWidth="-Infinity" prefWidth="60.0" promptText="Port" HBox.hgrow="NEVER" />
-	            <Button fx:id="connectButton" maxWidth="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#toggleConnection" prefWidth="80.0" text="Connect" HBox.hgrow="NEVER">
+                        <TextField fx:id="serverPortField" minWidth="-Infinity" prefWidth="60.0" promptText="Port"
+                                   HBox.hgrow="NEVER"/>
+                        <Button fx:id="connectButton" maxWidth="-Infinity" minWidth="-Infinity" mnemonicParsing="false"
+                                onAction="#toggleConnection" prefWidth="80.0" text="Connect" HBox.hgrow="NEVER">
                             <HBox.margin>
                                 <Insets left="5.0"/>
                             </HBox.margin>
@@ -64,7 +71,8 @@
         <HBox spacing="5.0">
             <children>
                 <TextField fx:id="messageField" onAction="#message" HBox.hgrow="ALWAYS"/>
-            <Button fx:id="sendButton" alignment="CENTER" maxWidth="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#message" prefWidth="50.0" text="Send" textAlignment="CENTER">
+                <Button fx:id="sendButton" alignment="CENTER" maxWidth="-Infinity" minWidth="-Infinity"
+                        mnemonicParsing="false" onAction="#message" prefWidth="50.0" text="Send" textAlignment="CENTER">
                     <HBox.margin>
                         <Insets left="5.0"/>
                     </HBox.margin>

protocol/src/main/java/ch/zhaw/pm2/multichat/protocol/ConnectionHandler.java

@@ -3,86 +3,92 @@ package ch.zhaw.pm2.multichat.protocol;
 import java.io.EOFException;
 import java.io.IOException;
 import java.net.SocketException;
-import java.util.Scanner;
 
+/**
+ * This abstract class is the superclass for ClientConnectionHandler and ServerConnectionHandler
+ * It offers the DATA_TYPE for message and a {@link State} enum for all valid connection states.
+ * Shared methods are implemented in this class as well {@link ConnectionHandler#sendData(String, String, DATA_TYPE, String)}
+ */
 public abstract class ConnectionHandler {
     private NetworkHandler.NetworkConnection<String> connection;
 
-    // Data types used for the Chat Protocol
-    private static final String DATA_TYPE_CONNECT = "CONNECT";
-    private static final String DATA_TYPE_CONFIRM = "CONFIRM";
-    private static final String DATA_TYPE_DISCONNECT = "DISCONNECT";
-    private static final String DATA_TYPE_MESSAGE = "MESSAGE";
-    private static final String DATA_TYPE_ERROR = "ERROR";
-
     public static final String USER_NONE = "";
     public static final String USER_ALL = "*";
 
+    // State of the connection
     public enum State {
         NEW, CONFIRM_CONNECT, CONNECTED, CONFIRM_DISCONNECT, DISCONNECTED, ERROR;
     }
 
-    public static String getDataTypeConnect() {
-        return DATA_TYPE_CONNECT;
+    // DATA_TYPE of the messages
+    public enum DATA_TYPE {
+        DATA_TYPE_CONNECT, DATA_TYPE_CONFIRM, DATA_TYPE_DISCONNECT, DATA_TYPE_MESSAGE, DATA_TYPE_ERROR
     }
 
-    public static String getDataTypeConfirm() {
-        return DATA_TYPE_CONFIRM;
+    /**
+     * @return {@link DATA_TYPE}
+     */
+    public static DATA_TYPE getDataTypeConnect() {
+        return DATA_TYPE.DATA_TYPE_CONNECT;
     }
 
-    public static String getDataTypeDisconnect() {
-        return DATA_TYPE_DISCONNECT;
+    /**
+     * @return {@link DATA_TYPE}
+     */
+    public static DATA_TYPE getDataTypeConfirm() {
+        return DATA_TYPE.DATA_TYPE_CONFIRM;
     }
 
-    public static String getDataTypeMessage() {
-        return DATA_TYPE_MESSAGE;
+    /**
+     * @return {@link DATA_TYPE}
+     */
+    public static DATA_TYPE getDataTypeDisconnect() {
+        return DATA_TYPE.DATA_TYPE_DISCONNECT;
     }
 
-    public static String getDataTypeError() {
-        return DATA_TYPE_ERROR;
+    /**
+     * @return {@link DATA_TYPE}
+     */
+    public static DATA_TYPE getDataTypeMessage() {
+        return DATA_TYPE.DATA_TYPE_MESSAGE;
     }
 
+    /**
+     * @return {@link DATA_TYPE}
+     */
+    public static DATA_TYPE getDataTypeError() {
+        return DATA_TYPE.DATA_TYPE_ERROR;
+    }
+
+    /**
+     * @return {@link NetworkHandler.NetworkConnection}
+     */
     public NetworkHandler.NetworkConnection<String> getConnection() {
         return connection;
     }
 
+    /**
+     * This method sets the NetworkConnection used for the server <-> client connection
+     *
+     * @param connection NetworkConnection used for the server <-> client connection
+     */
     protected void setConnection(NetworkHandler.NetworkConnection<String> connection) {
         this.connection = connection;
     }
 
-    protected void processData(Scanner scanner, StringBuilder sender, StringBuilder reciever, StringBuilder type, StringBuilder payload) throws ChatProtocolException {
-        // parse data content
-        if (scanner.hasNextLine()) {
-            sender.append(scanner.nextLine());
-        } else {
-            throw new ChatProtocolException("No Sender found");
-        }
-        if (scanner.hasNextLine()) {
-            reciever.append(scanner.nextLine());
-        } else {
-            throw new ChatProtocolException("No Reciever found");
-        }
-        if (scanner.hasNextLine()) {
-            type.append(scanner.nextLine());
-        } else {
-            throw new ChatProtocolException("No Type found");
-        }
-        if (scanner.hasNextLine()) {
-            payload.append(scanner.nextLine());
-        }
-    }
 
-    protected void sendData(String sender, String receiver, String type, String payload) {
+    /**
+     * This method gets called to send data via the socket defined in the {@link NetworkHandler.NetworkConnection}
+     *
+     * @param sender   of the data
+     * @param receiver of the data
+     * @param type     of the data
+     * @param payload  of the data
+     */
+    protected void sendData(String sender, String receiver, DATA_TYPE type, String payload) {
         if (connection.isAvailable()) {
-            new StringBuilder();
-            String data = new StringBuilder()
-                    .append(sender+"\n")
-                    .append(receiver+"\n")
-                    .append(type+"\n")
-                    .append(payload+"\n")
-                    .toString();
             try {
-                getConnection().send(data);
+                connection.send(new Message(type, sender, receiver, payload));
             } catch (SocketException e) {
                 System.err.println("Connection closed: " + e.getMessage());
             } catch (EOFException e) {

protocol/src/main/java/ch/zhaw/pm2/multichat/protocol/Message.java

@@ -0,0 +1,69 @@
+package ch.zhaw.pm2.multichat.protocol;
+
+import java.io.Serializable;
+
+/**
+ * A Message object represents one Message of a client. Can be stored in ClientMessageList.
+ */
+public class Message implements Serializable {
+    private final ConnectionHandler.DATA_TYPE type;
+    private final String sender;
+    private final String receiver;
+    private final String text;
+
+    /**
+     * Constructor of Message. Needs all Information about a Message to save them.
+     *
+     * @param type     Message (if it's a message typed by a user), Error or Information (if it is generated automatically, in this case sender and receiver will be null)
+     * @param sender   The User who has sent the message.
+     * @param receiver The User who should receive the message.
+     * @param text     The Text of the message.
+     */
+    public Message(ConnectionHandler.DATA_TYPE type, String sender, String receiver, String text) {
+        this.type = type;
+        this.sender = sender;
+        this.receiver = receiver;
+        this.text = text;
+    }
+
+    /**
+     * Checks if the Filter String is contained in one of the data fields sender, receiver or text
+     *
+     * @param filter The Filter String
+     * @return true if it is the Filter String is contained in a data field.
+     */
+    public boolean matchesFilter(String filter) {
+        return (sender != null && sender.contains(filter)) ||
+                (receiver != null && receiver.contains(filter)) ||
+                (text != null && text.contains(filter));
+    }
+
+    /**
+     * @return The type of the message.
+     */
+    public ConnectionHandler.DATA_TYPE getType() {
+        return type;
+    }
+
+    /**
+     * @return The User who has sent the Message.
+     */
+    public String getSender() {
+        return sender;
+    }
+
+    /**
+     * @return The Receiver who receives the Message.
+     */
+    public String getReceiver() {
+        return receiver;
+    }
+
+    /**
+     * @return The Text of the Message.
+     */
+    public String getText() {
+        return text;
+    }
+
+}

protocol/src/main/java/ch/zhaw/pm2/multichat/protocol/NetworkHandler.java

@@ -38,7 +38,7 @@ import java.util.Objects;
  *             on the client side, usually the result is displayed to the user). After processing is finished the
  *             process calls {@link NetworkConnection#receive()} again to wait for the next request.
  *             </li>
- *             <li>sending data: call {@link NetworkConnection#send(Serializable data)}, which sends the given data
+ *             <li>sending data: call {@link NetworkConnection#send(Message)}, which sends the given data
  *             object to the remote side. The method returns as soon the object has been transmitted.
  *             <b>Important: {@link NetworkConnection} is not thread safe</b>, therefore make sure that only one thread
  *             at a time is sending data.</li>
@@ -270,7 +270,7 @@ public class NetworkHandler {
      *         on the client side, usually the result is displayed to the user). After processing is finished the
      *         process calls {@link NetworkConnection#receive()} again to wait for the next request.
      *     </li>
-     *     <li>sending data: call {@link NetworkConnection#send(Serializable data)}, which sends the given data
+     *     <li>sending data: call {@link NetworkConnection#send(Message)}, which sends the given data
      *         object to the remote side. The method returns as soon the object has been transmitted.
      *         <b>Important: {@link NetworkConnection} is not thread safe</b>, therefore make sure that only one thread
      *         at a time is sending data.
@@ -305,7 +305,7 @@ public class NetworkHandler {
          * @param data  data object of type T to be submitted through the connection.
          * @throws IOException if an error occurs (e.g. connection interrupted while sending, ...)
          */
-        public synchronized void send(T data) throws IOException {
+        public synchronized void send(Message data) throws IOException {
             ObjectOutputStream outputStream = new ObjectOutputStream(socket.getOutputStream());
             outputStream.writeObject(data);
         }
@@ -320,9 +320,9 @@ public class NetworkHandler {
          * @throws IOException if an error occours. (e.g. terminated locally/remotely) see above.
          * @throws ClassNotFoundException if the data object received does not match any class in the local classpath
          */
-        public T receive() throws IOException, ClassNotFoundException {
+        public Message receive() throws IOException, ClassNotFoundException {
             ObjectInputStream inputStream = new ObjectInputStream(this.socket.getInputStream());
-            return (T) inputStream.readObject();
+            return (Message) inputStream.readObject();
         }
 
         /**

server/src/main/java/ch/zhaw/pm2/multichat/server/Server.java

@@ -1,14 +1,12 @@
 package ch.zhaw.pm2.multichat.server;
 
-import ch.zhaw.pm2.multichat.protocol.ConnectionHandler;
 import ch.zhaw.pm2.multichat.protocol.NetworkHandler;
 
 import java.io.IOException;
 import java.net.SocketException;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.concurrent.locks.Condition;
-import java.util.concurrent.locks.ReentrantLock;
+
 
 /**
  * This Class represents a Server. The user can start the programm with the port number as a argument.
@@ -16,17 +14,32 @@ import java.util.concurrent.locks.ReentrantLock;
  * After initialising the server:
  * 1. Starts a Socketserver using the logic given in {@link NetworkHandler.NetworkServer#createServer()}
  * 2. The server starts to listen for incoming connection using the Logic given in {@link NetworkHandler.NetworkServer#waitForConnection()}
- * 3. New conections will be atached to a Connectionhandler: {@link ServerConnectionHandler} and placed in a Map containing all active connections {@link Server#connections}
- *
+ * 3. New connections will be attached to a Connection handler: {@link ServerConnectionHandler} and placed in a Map containing all active connections {@link Server#connections}
  */
 public class Server {
 
     // Server connection
-    private NetworkHandler.NetworkServer<String> networkServer;
+    private final NetworkHandler.NetworkServer<String> networkServer;
 
     // Connection registry
-    private Map<String,ServerConnectionHandler> connections = new HashMap<>();
+    private final Map<String, ServerConnectionHandler> connections = new HashMap<>();
 
+    /**
+     * The Constructor to create a new instance.
+     *
+     * @param serverPort to listen for incoming connections.
+     * @throws IOException thrown if an I/O error occurs when opening the socket.
+     */
+    public Server(int serverPort) throws IOException {
+        // Open server connection
+        System.out.println("Create server connection");
+        networkServer = NetworkHandler.createServer(serverPort);
+        System.out.println("Listening on " + networkServer.getHostAddress() + ":" + networkServer.getHostPort());
+    }
+
+    /**
+     * @param args
+     */
     public static void main(String[] args) {
         // Parse arguments for server port.
         try {
@@ -65,30 +78,16 @@ public class Server {
         }
     }
 
-    /**
-     * The Constructor to create a new instance.
-     * @param serverPort to listen for incoming connections.
-     * @throws IOException thrown if an I/O error occurs when opening the socket.
-     */
-    public Server(int serverPort) throws IOException {
-        // Open server connection
-        System.out.println("Create server connection");
-        networkServer = NetworkHandler.createServer(serverPort);
-        System.out.println("Listening on " + networkServer.getHostAddress() + ":" + networkServer.getHostPort());
-    }
-
     /**
      * With this methode the instance waits for incoming connections. If a client tries to connect to the server.
      * The connection will be registered in the connection registry if successful.
      */
     private void start() {
-        ReentrantLock mutex = new ReentrantLock();
-        Condition nameComplete = mutex.newCondition();
         System.out.println("Server started.");
         try {
-            while (true) {
+            while (networkServer.isAvailable()) {
                 NetworkHandler.NetworkConnection<String> connection = networkServer.waitForConnection();
-                 ServerConnectionHandler connectionHandler = new ServerConnectionHandler(connection, connections, mutex, nameComplete);
+                ServerConnectionHandler connectionHandler = new ServerConnectionHandler(connection, connections);
                 new Thread(connectionHandler).start();
             }
         } catch (SocketException e) {

server/src/main/java/ch/zhaw/pm2/multichat/server/ServerConnectionHandler.java

@@ -2,7 +2,10 @@ package ch.zhaw.pm2.multichat.server;
 
 import ch.zhaw.pm2.multichat.protocol.ChatProtocolException;
 import ch.zhaw.pm2.multichat.protocol.ConnectionHandler;
+
 import static ch.zhaw.pm2.multichat.protocol.ConnectionHandler.State.*;
+
+import ch.zhaw.pm2.multichat.protocol.Message;
 import ch.zhaw.pm2.multichat.protocol.NetworkHandler;
 
 import java.io.EOFException;
@@ -12,44 +15,39 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.Scanner;
 import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.ReentrantLock;
 
 
 /**
  * This class represents the connection between the server and a client and offers the serverside logic.
  * The ServerConnectionHandler receives data send from the client as well as sends data to the client.
- *
+ * <p>
  * The ServeConnectionHandler offers following functionality:
- *
+ * <p>
  * Evaluating connection attempts from a client by:
  * 1. Checks if Username is valid (Not used)
  * 2. Saves Username in {@link ServerConnectionHandler#userName}
  * 3. Saves the connection in the {@link ServerConnectionHandler#connectionRegistry}
- *
+ * <p>
  * Processes disconnections from a client by:
  * 1. Removing the connection from the {@link ServerConnectionHandler#connectionRegistry}
  * 2. Terminates the socket by calling {@link NetworkHandler.NetworkConnection#close()}
- *
- * Processes Messages send from a client by:
- * 1. Evaluating the reciever by differentiating between broadcast or unicast.
+ * <p>
+ * Process Messages send from a client by:
+ * 1. Evaluating the receiver by differentiating between broadcast or unicast.
  * 2. Sending the message accordingly.
- *
+ * <p>
  * To use this class, start a new instance and start it in a thread.
  * To constructor needs following parameter:
  * 1. {@link ch.zhaw.pm2.multichat.protocol.NetworkHandler.NetworkConnection} representing the socket connection between server and client
  * 2. {@link Map<String,ServerConnectionHandler>} registry to check for all active connections
  * 3. {@link ReentrantLock @link Condition} to lock server thread to evaluate connection.
- * */
+ */
 public class ServerConnectionHandler extends ConnectionHandler implements Runnable {
     private static final AtomicInteger connectionCounter = new AtomicInteger(0);
     private final int connectionId = connectionCounter.incrementAndGet();
     private final Map<String, ServerConnectionHandler> connectionRegistry;
 
-    private ReentrantLock mutex;
-
-    private Condition nameComplete;
-
     private String userName = "Anonymous-" + connectionId;
     private State state = NEW;
 
@@ -62,41 +60,22 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
     }
 
     /**
-     * Constructor to intitialize the connection
-     * @param connection representing the socket connection between server and clinet
+     * Constructor to initialize the connection
+     *
+     * @param connection representing the socket connection between server and client
      * @param registry   map containing all active connections between server and clients
-     * @param mutex to lock thread
-     * @param nameComplete condition to call threads
      */
     public ServerConnectionHandler(NetworkHandler.NetworkConnection<String> connection,
-                                   Map<String,ServerConnectionHandler> registry, ReentrantLock mutex, Condition nameComplete) {
+                                   Map<String, ServerConnectionHandler> registry) {
         super();
         setConnection(connection);
         Objects.requireNonNull(connection, "Connection must not be null");
         Objects.requireNonNull(registry, "Registry must not be null");
         this.connectionRegistry = registry;
-        this.mutex = mutex;
-        this.nameComplete = nameComplete;
     }
 
     /**
-     *
-     * @return the username of the connected client
-     */
-    public String getUserName() {
-        return this.userName;
-    }
-
-    /**
-     *
-     * @return state of the connection. Poosible states are see {@link ch.zhaw.pm2.multichat.protocol.ConnectionHandler.State}
-     */
-    public State getState() {
-        return state;
-    }
-
-    /**
-     * This methods runs in a whileloop as long as the socket between server and client is available
+     * These methods runs in a while-loop as long as the socket between server and client is available
      * and the connection State is not ERROR.
      */
     private void startReceiving() {
@@ -104,10 +83,10 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
         try {
             System.out.println("Start receiving data...");
             while (getConnection().isAvailable() && !(state == ERROR)) {
-                    String data = getConnection().receive();
+                Message data = getConnection().receive();
                 processData(data);
             }
-                System.out.println("Stopped recieving data");
+            System.out.println("Stopped receiving data");
         } catch (SocketException e) {
             System.out.println("Connection terminated locally");
             connectionRegistry.remove(userName);
@@ -145,38 +124,32 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
     }
 
     /**
-     * This method gets called when socket recieves data. The method checks for the data type and reacts accordingly
+     * This method gets called when socket receives data. The method checks for the data type and reacts accordingly
      * If data type:
      * 1. Connect => checks if username is valid. if valid sends response to client with confirmation.
      * If username not valid quits connection by changing status to ERROR.
-     * 2. Confirm => Server should not recieve this kind of message. STDOUT informs about it.
+     * 2. Confirm => Server should not receive this kind of message. STDOUT informs about it.
      * 3. Disconnect => Disconnects connection by removing connection from registry and calling method to terminate socket.
      * 4. Message => Checks if broadcast or unicast. Sends data accordingly
      * 5. Error => STDERR message
-     * @param data recieved by the server
+     *
+     * @param data received by the server
      */
-    private void processData(String data)  {
+    private void processData(Message data) {
         try {
-            Scanner scanner = new Scanner(data);
-            StringBuilder sender = new StringBuilder();
-            StringBuilder reciever = new StringBuilder();
-            StringBuilder type = new StringBuilder();
-            StringBuilder payload = new StringBuilder();
-            super.processData(scanner,sender,reciever,type,payload);
-
             // dispatch operation based on type parameter
-            if (type.toString().equals(getDataTypeConnect())) {
-                caseConnect(sender.toString());
-            } else if (type.toString().equals(getDataTypeConfirm())) {
+            if (data.getType() == DATA_TYPE.DATA_TYPE_CONNECT) {
+                caseConnect(data);
+            } else if (data.getType() == DATA_TYPE.DATA_TYPE_CONFIRM) {
                 System.out.println("Not expecting to receive a CONFIRM request from client");
-            } else if (type.toString().equals(getDataTypeDisconnect())) {
+            } else if (data.getType() == DATA_TYPE.DATA_TYPE_DISCONNECT) {
                 caseDisconnect();
-            } else if (type.toString().equals(getDataTypeMessage())) {
-                caseMessage(sender.toString(), reciever.toString(), type.toString(), payload.toString());
-            } else if (type.toString().equals(getDataTypeError())) {
-                System.err.println("Received error from client (" + sender + "): " + payload);
+            } else if (data.getType() == DATA_TYPE.DATA_TYPE_MESSAGE) {
+                caseMessage(data);
+            } else if (data.getType() == DATA_TYPE.DATA_TYPE_ERROR) {
+                System.err.println("Received error from client (" + data.getSender() + "): " + data.getText());
             } else {
-                System.err.println("Unknown data type received: " + type);
+                System.err.println("Unknown data type received: " + data.getType());
 
             }
         } catch (ChatProtocolException e) {
@@ -186,26 +159,28 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
     }
 
     /**
-     * This method is called by method {@link ServerConnectionHandler#processData(String)}
+     * This method is called by method {@link ServerConnectionHandler#processData(Message)}
      * Checks if username is valid. if valid sends response to client with confirmation.
-     * @param sender of the payload
+     *
+     * @param data sent
      * @throws ChatProtocolException if username not valid
      */
-    private void caseConnect(String sender) throws ChatProtocolException {
+    private void caseConnect(Message data) throws ChatProtocolException {
         if (this.state != NEW) throw new ChatProtocolException("Illegal state for connect request: " + state);
-        if (sender.isBlank()) sender = this.userName;
         //if username not valid
-        if (connectionRegistry.containsKey(sender)) {
+        if (connectionRegistry.containsKey(data.getSender())) {
             state = ERROR;
             System.out.println(String.format("Connecting failed for new Client with IP:Port <%s:%d>.\nReason: Name already taken.",
                     getConnection().getRemoteHost(),
                     getConnection().getRemotePort()));
-            throw new ChatProtocolException("User name already taken: " + sender);
+            throw new ChatProtocolException("User name already taken: " + data.getSender());
         }
         //if username valid
-        this.userName = sender;
+        if (!data.getSender().isBlank()) {
+            this.userName = data.getSender();
+        }
         connectionRegistry.put(userName, this);
-        sendData(USER_NONE, userName, getDataTypeConfirm(), "Registration successfull for " + userName);
+        sendData(USER_NONE, userName, getDataTypeConfirm(), "Registration successful for " + userName);
         this.state = CONNECTED;
         System.out.println(String.format("Connected new Client %s with IP:Port <%s:%d>",
                 userName,
@@ -214,9 +189,10 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
     }
 
     /**
-     * This method is called by method {@link ServerConnectionHandler#processData(String)}
+     * This method is called by method {@link ServerConnectionHandler#processData(Message)}
      * Disconnects connection by removing connection from registry and calling method {@link ServerConnectionHandler#stopReceiving()} to terminate socket.
-     * @throws ChatProtocolException if state allready DISCONNECTED.
+     *
+     * @throws ChatProtocolException if state already DISCONNECTED.
      */
     private void caseDisconnect() throws ChatProtocolException {
         if (state == DISCONNECTED)
@@ -230,29 +206,27 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
     }
 
     /**
-     * This method is called by method {@link ServerConnectionHandler#processData(String)}
+     * This method is called by method {@link ServerConnectionHandler#processData(Message)}
      * Checks if broadcast or unicast. Sends data accordingly
-     * @param sender who sent data
-     * @param reciever to recieve data
-     * @param type of message
-     * @param payload data to transmit
+     *
+     * @param data to transmit
      * @throws ChatProtocolException if state not equal to CONNECT
      */
-    private void caseMessage(String sender, String reciever, String type, String payload) throws ChatProtocolException{
+    private void caseMessage(Message data) throws ChatProtocolException {
         if (state != CONNECTED) throw new ChatProtocolException("Illegal state for message request: " + state);
-        if (USER_ALL.equals(reciever)) {
+        if (USER_ALL.equals(data.getReceiver())) {
             for (ServerConnectionHandler handler : connectionRegistry.values()) {
-                handler.sendData(sender, reciever, type, payload);
+                handler.sendData(data.getSender(), data.getReceiver(), data.getType(), data.getText());
             }
         } else {
-            ServerConnectionHandler handler = connectionRegistry.get(reciever);
+            ServerConnectionHandler handler = connectionRegistry.get(data.getReceiver());
             if (handler != null) {
-                handler.sendData(sender, reciever, type, payload);
-                if(!reciever.equals(sender)){
-                    sendData(sender, reciever, type, payload); //send message to sender if it's a direct message and sender is not receiver.
+                handler.sendData(data.getSender(), data.getReceiver(), data.getType(), data.getText());
+                if (!data.getReceiver().equals(data.getSender())) {
+                    sendData(data.getSender(), data.getReceiver(), data.getType(), data.getText()); //send message to sender if it's a direct message and sender is not receiver.
                 }
             } else {
-                this.sendData(USER_NONE, userName, getDataTypeError(), "Unknown User: " + reciever);
+                this.sendData(USER_NONE, userName, getDataTypeError(), "Unknown User: " + data.getReceiver());
             }
         }
     }