Merge pull request #87 from informatik-ag-ngl/standalone_server_integration

Standalone server integration

.classpath

@@ -28,11 +28,5 @@
 			<attribute name="maven.pomderived" value="true"/>
 		</attributes>
 	</classpathentry>
-	<classpathentry excluding="**" kind="src" output="target/test-classes" path="src/test/resources">
-		<attributes>
-			<attribute name="maven.pomderived" value="true"/>
-			<attribute name="test" value="true"/>
-		</attributes>
-	</classpathentry>
 	<classpathentry kind="output" path="target/classes"/>
 </classpath>

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>informatik-ag-ngl</groupId>
 	<artifactId>envoy-client</artifactId>
-	<version>0.0.1-SNAPSHOT</version>
+	<version>0.3-alpha</version>
 
 	<name>Envoy Client</name>
 	<url>https://github.com/informatik-ag-ngl/envoy-client</url>
@@ -18,20 +18,10 @@
 	</properties>
 
 	<dependencies>
-		<dependency>
-			<groupId>org.jboss.resteasy</groupId>
-			<artifactId>resteasy-client</artifactId>
-			<version>4.1.1.Final</version>
-		</dependency>
-		<dependency>
-			<groupId>org.jboss.resteasy</groupId>
-			<artifactId>resteasy-jaxb-provider</artifactId>
-			<version>4.3.1.Final</version>
-		</dependency>
 		<dependency>
 			<groupId>informatik-ag-ngl</groupId>
 			<artifactId>envoy-common</artifactId>
-			<version>0.0.1-SNAPSHOT</version>
+			<version>0.2-alpha</version>
 		</dependency>
 	</dependencies>
 

src/main/java/envoy/client/Chat.java

@@ -4,8 +4,8 @@ import java.io.Serializable;
 
 import javax.swing.DefaultListModel;
 
-import envoy.schema.Message;
+import envoy.data.Message;
-import envoy.schema.User;
+import envoy.data.User;
 
 /**
  * Represents a chat between two {@link User}s <br>

src/main/java/envoy/client/Client.java

@@ -1,23 +1,17 @@
 package envoy.client;
 
-import java.io.StringWriter;
+import java.io.Closeable;
+import java.io.IOException;
+import java.net.Socket;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.logging.Logger;
 
-import javax.ws.rs.client.ClientBuilder;
+import javax.naming.TimeLimitExceededException;
-import javax.ws.rs.client.Entity;
-import javax.ws.rs.client.WebTarget;
-import javax.ws.rs.core.Response;
-import javax.xml.bind.JAXBContext;
-import javax.xml.bind.JAXBException;
-import javax.xml.bind.Marshaller;
 
 import envoy.client.util.EnvoyLog;
-import envoy.exception.EnvoyException;
+import envoy.data.*;
-import envoy.schema.ObjectFactory;
+import envoy.util.SerializationUtils;
-import envoy.schema.Sync;
-import envoy.schema.User;
 
 /**
  * Project: <strong>envoy-client</strong><br>
@@ -29,46 +23,80 @@ import envoy.schema.User;
  * @author Leon Hofmeister
  * @since Envoy v0.1-alpha
  */
-public class Client {
+public class Client implements Closeable {
 
-	private ObjectFactory	objectFactory	= new ObjectFactory();
+	private Socket		socket;
-	private Config			config;
+	private Receiver	receiver;
-	private User			sender, recipient;
+	private boolean		online;
-	private boolean			online			= false;
+
+	private volatile User	sender;
+	private User			recipient;
+
+	private volatile Contacts contacts;
+
+	private Config config = Config.getInstance();
 
 	private static final Logger logger = EnvoyLog.getLogger(Client.class.getSimpleName());
 
 	/**
-	 * Initializes the client. At this state, the client user has yet to be
+	 * Enters the online mode by acquiring a user ID from the server. As a
-	 * initialized, which can be done by calling {@link Client#onlineInit(String)}.
+	 * connection has to be established and a handshake has to be made, this method
+	 * will block for up to 5 seconds. If the handshake does exceed this time limit,
+	 * an exception is thrown.
 	 *
-	 * @param config The {@link Config} instance to use in this client
+	 * @param credentials the login credentials of the user
+	 * @throws Exception if the online mode could not be entered or the request
+	 *                   failed for some other reason
 	 * @since Envoy v0.2-alpha
 	 */
-	public Client(Config config) { this.config = config; }
+	public void onlineInit(LoginCredentials credentials) throws Exception {
+		// Establish TCP connection
+		logger.info(String.format("Attempting connection to server %s:%d...", config.getServer(), config.getPort()));
+		socket = new Socket(config.getServer(), config.getPort());
+		logger.info("Successfully connected to server.");
 
-	/**
+		// Create message receiver
-	 * Enters the online mode by acquiring a user ID from the server.
+		receiver = new Receiver(socket.getInputStream());
-	 *
+
-	 * @param userName the name of the client user
+		// Register user creation processor
-	 * @throws EnvoyException if the online mode could not be entered or the request
+		receiver.registerProcessor(User.class, sender -> { logger.info("Acquired user object " + sender); this.sender = sender; });
-	 *                        failed for some other reason
+		receiver.registerProcessor(Contacts.class, contacts -> { logger.info("Acquired contacts object " + contacts); this.contacts = contacts; });
-	 * @since Envoy v0.2-alpha
+
-	 */
+		// Start receiver
-	public void onlineInit(String userName) throws EnvoyException {
+		new Thread(receiver).start();
-		sender	= getUser(userName);
+
-		online	= true;
+		// Write login credentials
+		logger.finest("Sending login credentials...");
+		SerializationUtils.writeBytesWithLength(credentials, socket.getOutputStream());
+
+		// Wait for a maximum of five seconds to acquire the sender object
+		long start = System.currentTimeMillis();
+		while (sender == null || contacts == null) {
+			if (System.currentTimeMillis() - start > 5000) throw new TimeLimitExceededException("Did not log in after 5 seconds");
+			Thread.sleep(500);
+		}
+
+		logger.info("Handshake completed.");
+		online = true;
+
+		// Remove user creation processor
+		receiver.removeAllProcessors();
+
+		// Register processors for message and status handling
+		receiver.registerProcessor(Message.class, new ReceivedMessageProcessor());
 	}
 
-	private <T, R> R post(String uri, T body, Class<R> responseBodyClass) {
+	/**
-		javax.ws.rs.client.Client	client			= ClientBuilder.newClient();
+	 * Sends a message to the server.
-		WebTarget					target			= client.target(uri);
+	 * 
-		Response					response		= target.request().post(Entity.entity(body, "application/xml"));
+	 * @param message the message to send
-		R							responseBody	= response.readEntity(responseBodyClass);
+	 * @throws IOException if the message does not reach the server
-		response.close();
+	 * @since Envoy v0.3-alpha
-		client.close();
+	 */
-
+	public void sendMessage(Message message) throws IOException {
-		return responseBody;
+		checkOnline();
+		SerializationUtils.writeBytesWithLength(message, socket.getOutputStream());
+		message.nextStatus();
 	}
 
 	/**
@@ -77,107 +105,16 @@ public class Client {
 	 * @since Envoy v0.2-alpha
 	 */
 	public Map<String, User> getUsers() {
-		Sync	sendSync	= objectFactory.createSync();
+		checkOnline();
-		User	user		= objectFactory.createUser();
-		user.setID(-1);
-		sendSync.getUsers().add(user);
-
-		Sync returnSync = post(String.format("%s:%d/envoy-server/rest/sync/syncData?userId=%d", config.getServer(), config.getPort(), 0),
-				sendSync,
-				Sync.class);
-
 		Map<String, User> users = new HashMap<>();
-		returnSync.getUsers().forEach(u -> users.put(u.getName(), u));
+		contacts.getContacts().forEach(u -> users.put(u.getName(), u));
 		return users;
 	}
 
-	/**
+	@Override
-	 * Returns a {@link User} with a specific id by name.
+	public void close() throws IOException { if (online) socket.close(); }
-	 *
-	 * @param name - the name of the {@link User}
-	 * @return a {@link User} with the specified name
-	 * @throws EnvoyException if the server does not return the requested ID
-	 * @since Envoy v0.1-alpha
-	 */
-	private User getUser(String name) throws EnvoyException {
-		// Create a sync with only a user with the requested name
-		Sync	senderSync	= objectFactory.createSync();
-		User	user		= objectFactory.createUser();
-		user.setName(name);
-		senderSync.getUsers().add(user);
 
-		try {
+	private void checkOnline() { if (!online) throw new IllegalStateException("Client is not online"); }
-			Sync sync = post(String.format("%s:%d/envoy-server/rest/sync/syncData?userId=%d", config.getServer(), config.getPort(), 0),
-					senderSync,
-					Sync.class);
-
-			// Expecting a single user with an ID
-			if (sync.getUsers().size() == 1) {
-				online = true;
-				return sync.getUsers().get(0);
-			} else throw new EnvoyException("Unexpected response from Envoy Server");
-		} catch (Exception e) {
-			throw new EnvoyException("Could not connect to server", e);
-		}
-	}
-
-	/**
-	 * Sends the "sync" Sync Object to the server and gets a "returnSync" Sync
-	 * Object as response. <br>
-	 * It is also used to get the own sender at the start of the client
-	 * (Client sends "sync" Sync Object with single user in it(name: the name
-	 * entered at login, id: 0, UserStatus:null))<br>
-	 * and to get a complete list of all users saved on the server.
-	 * (Client sends "sync" Sync Object with single user in it(name: "" (empty), id:
-	 * -1, UserStatus:null)) <br>
-	 * This method also processes the response Sync Object. <br>
-	 * It sorts its users and messages by specific variables and does certain things
-	 * with them. <br>
-	 * <br>
-	 * Messages: <br>
-	 * -State SENT: Update Local message(s) with State WAITING (add Message ID and
-	 * change State to SENT). (server sends these informations to the client if
-	 * message(s) with State WAITING were successfully sent to the server)<br>
-	 * -State RECEIVED, SenderID != 0: Adds the unread Messages returned from the
-	 * server in the latest sync to the "unreadMessagesSync" Sync Object. <br>
-	 * -State RECEIVED, SenderID == 0: Update message(s) in localDB to state
-	 * RECEIVED.
-	 * (server sends these informations to the client if the other client received
-	 * the message(s).) <br>
-	 * -State READ: Update message(s) in the LocalDB to state READ. (server sends
-	 * these informations to the client if the other client read
-	 * the message(s).) <br>
-	 * <br>
-	 * Users: <br>
-	 * Updating UserStatus of all users in LocalDB. (Server sends all users with
-	 * their updated UserStatus to the client.) <br>
-	 *
-	 * @param userId the id of the {@link Client} who sends the {@link Sync}
-	 * @param sync   the sync object (yet to be converted from java class to
-	 *               sync.xml)
-	 * @return a returnSync.xml file
-	 * @throws EnvoyException if the client is not in online mode
-	 * @since Envoy v0.1-alpha
-	 */
-	public Sync sendSync(long userId, Sync sync) throws EnvoyException {
-		if(!isOnline())
-			throw new EnvoyException("Client is not in online mode");
-		// Print sync XML to console
-		JAXBContext jc;
-		try {
-			jc = JAXBContext.newInstance("envoy.schema");
-			Marshaller m = jc.createMarshaller();
-			m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
-			StringWriter stringWriter = new StringWriter();
-			m.marshal(sync, stringWriter);
-			logger.fine("Sending sync:\n" + stringWriter.toString());
-		} catch (JAXBException e) {
-			e.printStackTrace();
-		}
-
-		// Send sync
-		return post(String.format("%s:%d/envoy-server/rest/sync/syncData?userId=%d", config.getServer(), config.getPort(), userId), sync, Sync.class);
-	}
 
 	/**
 	 * @return the sender object that represents this client.
@@ -213,6 +150,11 @@ public class Client {
 	 */
 	public boolean hasRecipient() { return recipient != null; }
 
+	/**
+	 * @return the {@link Receiver} used by this {@link Client}
+	 */
+	public Receiver getReceiver() { return receiver; }
+
 	/**
 	 * @return {@code true} if a connection to the server could be established
 	 * @since Envoy v0.2-alpha

src/main/java/envoy/client/LocalDB.java

@@ -2,20 +2,10 @@ package envoy.client;
 
 import java.io.File;
 import java.io.IOException;
-import java.time.Instant;
 import java.util.*;
-import java.util.logging.Logger;
 
-import javax.xml.datatype.DatatypeConfigurationException;
+import envoy.data.User;
-import javax.xml.datatype.DatatypeFactory;
+import envoy.util.SerializationUtils;
-
-import envoy.client.event.EventBus;
-import envoy.client.event.MessageCreationEvent;
-import envoy.client.util.EnvoyLog;
-import envoy.client.util.SerializationUtils;
-import envoy.exception.EnvoyException;
-import envoy.schema.*;
-import envoy.schema.Message.Metadata.MessageState;
 
 /**
  * Project: <strong>envoy-client</strong><br>
@@ -33,15 +23,6 @@ public class LocalDB {
 	private Map<String, User>	users	= new HashMap<>();
 	private List<Chat>			chats	= new ArrayList<>();
 
-	private ObjectFactory	objectFactory	= new ObjectFactory();
-	private DatatypeFactory	datatypeFactory;
-
-	private Sync	unreadMessagesSync	= objectFactory.createSync();
-	private Sync	sync				= objectFactory.createSync();
-	private Sync	readMessages		= objectFactory.createSync();
-
-	private static final Logger logger = EnvoyLog.getLogger(LocalDB.class.getSimpleName());
-
 	/**
 	 * Constructs an empty local database. To serialize any chats to the file
 	 * system, call {@link LocalDB#initializeDBFile()}.
@@ -53,12 +34,6 @@ public class LocalDB {
 	public LocalDB(File localDBDir) throws IOException {
 		this.localDBDir = localDBDir;
 
-		try {
-			datatypeFactory = DatatypeFactory.newInstance();
-		} catch (DatatypeConfigurationException e) {
-			e.printStackTrace();
-		}
-
 		// Initialize local database directory
 		if (localDBDir.exists() && !localDBDir.isDirectory())
 			throw new IOException(String.format("LocalDBDir '%s' is not a directory!", localDBDir.getAbsolutePath()));
@@ -73,7 +48,7 @@ public class LocalDB {
 	 */
 	public void initializeDBFile() {
 		if (user == null) throw new NullPointerException("Client user is null");
-		localDBFile = new File(localDBDir, user.getID() + ".db");
+		localDBFile = new File(localDBDir, user.getId() + ".db");
 	}
 
 	/**
@@ -94,187 +69,20 @@ public class LocalDB {
 	/**
 	 * Loads all users that are stored in the local database.
 	 * 
-	 * @throws EnvoyException if the loading process failed
+	 * @throws IOException            if the loading process failed
+	 * @throws ClassNotFoundException if the loading process failed
 	 * @since Envoy v0.2-alpha
 	 */
-	public void loadUsers() throws EnvoyException { users = SerializationUtils.read(usersFile, HashMap.class); }
+	public void loadUsers() throws ClassNotFoundException, IOException { users = SerializationUtils.read(usersFile, HashMap.class); }
 
 	/**
 	 * Loads all chats saved by Envoy for the client user.
 	 * 
-	 * @throws EnvoyException if the loading process failed
+	 * @throws IOException            if the loading process failed
+	 * @throws ClassNotFoundException if the loading process failed
 	 * @since Envoy v0.1-alpha
 	 */
-	public void loadChats() throws EnvoyException { chats = SerializationUtils.read(localDBFile, ArrayList.class); }
+	public void loadChats() throws ClassNotFoundException, IOException { chats = SerializationUtils.read(localDBFile, ArrayList.class); }
-
-	/**
-	 * Creates a {@link Message} object serializable to XML.
-	 *
-	 * @param textContent The content (text) of the message
-	 * @param recipientID The recipient of the message
-	 * @return prepared {@link Message} object
-	 * @since Envoy v0.1-alpha
-	 */
-	public Message createMessage(String textContent, long recipientID) {
-		Message.Metadata metaData = objectFactory.createMessageMetadata();
-		metaData.setSender(user.getID());
-		metaData.setRecipient(recipientID);
-		metaData.setState(MessageState.WAITING);
-		metaData.setDate(datatypeFactory.newXMLGregorianCalendar(Instant.now().toString()));
-
-		Message.Content content = objectFactory.createMessageContent();
-		content.setType("text");
-		content.setText(textContent);
-
-		Message message = objectFactory.createMessage();
-		message.setMetadata(metaData);
-		message.getContent().add(content);
-
-		return message;
-	}
-
-	/**
-	 * Creates a {@link Sync} object filled with the changes that occurred to the
-	 * local database since the last synchronization.
-	 *
-	 * @param userId the ID of the user that is synchronized by this client
-	 * @return {@link Sync} object filled with the current changes
-	 * @since Envoy v0.1-alpha
-	 */
-	public Sync fillSync(long userId) {
-		addWaitingMessagesToSync();
-
-		sync.getMessages().addAll(readMessages.getMessages());
-		readMessages.getMessages().clear();
-
-		logger.finest(String.format("Filled sync with %d messages.", sync.getMessages().size()));
-		return sync;
-	}
-
-	/**
-	 * Applies the changes carried by a {@link Sync} object to the local database
-	 *
-	 * @param returnSync the {@link Sync} object to apply
-	 * @since Envoy v0.1-alpha
-	 */
-	public void applySync(Sync returnSync) {
-		for (int i = 0; i < returnSync.getMessages().size(); i++) {
-
-			// The message has an ID
-			if (returnSync.getMessages().get(i).getMetadata().getMessageId() != 0) {
-
-				// Messages are processes differently corresponding to their state
-				switch (returnSync.getMessages().get(i).getMetadata().getState()) {
-					case SENT:
-						// Update previously waiting and now sent messages that were assigned an ID by
-						// the server
-						sync.getMessages().get(i).getMetadata().setMessageId(returnSync.getMessages().get(i).getMetadata().getMessageId());
-						sync.getMessages().get(i).getMetadata().setState(returnSync.getMessages().get(i).getMetadata().getState());
-						break;
-					case RECEIVED:
-						if (returnSync.getMessages().get(i).getMetadata().getSender() != 0) {
-							// these are the unread Messages from the server
-							unreadMessagesSync.getMessages().add(returnSync.getMessages().get(i));
-
-							// Create and dispatch message creation event
-							EventBus.getInstance().dispatch(new MessageCreationEvent(returnSync.getMessages().get(i)));
-						} else {
-							// Update Messages in localDB to state RECEIVED
-							for (Chat chat : getChats())
-								if (chat.getRecipient().getID() == returnSync.getMessages().get(i).getMetadata().getRecipient())
-									for (int j = 0; j < chat.getModel().getSize(); j++)
-									if (chat.getModel().get(j).getMetadata().getMessageId() == returnSync.getMessages()
-										.get(i)
-										.getMetadata()
-										.getMessageId())
-										chat.getModel().get(j).getMetadata().setState(returnSync.getMessages().get(i).getMetadata().getState());
-						}
-						break;
-					case READ:
-						// Update local Messages to state READ
-						logger.info("Message with ID: " + returnSync.getMessages().get(i).getMetadata().getMessageId()
-								+ "was initialized to be set to READ in localDB.");
-						for (Chat chat : getChats())
-							if (chat.getRecipient().getID() == returnSync.getMessages().get(i).getMetadata().getRecipient()) {
-								logger.info("Chat with: " + chat.getRecipient().getID() + "was selected.");
-								for (int k = 0; k < chat.getModel().getSize(); k++)
-									if (chat.getModel().get(k).getMetadata().getMessageId() == returnSync.getMessages()
-										.get(i)
-										.getMetadata()
-										.getMessageId()) {
-										logger.info("Message with ID: " + chat.getModel().get(k).getMetadata().getMessageId() + "was selected.");
-										chat.getModel().get(k).getMetadata().setState(returnSync.getMessages().get(i).getMetadata().getState());
-										logger.info("Message State is now: " + chat.getModel().get(k).getMetadata().getState());
-									}
-							}
-						break;
-				}
-			}
-		}
-
-		// Updating UserStatus of all users in LocalDB
-		for (User user : returnSync.getUsers())
-			for (Chat chat : getChats())
-				if (user.getID() == chat.getRecipient().getID()) chat.getRecipient().setStatus(user.getStatus());
-
-		sync.getMessages().clear();
-		sync.getUsers().clear();
-	}
-
-	/**
-	 * Adds the unread messages returned from the server in the latest sync to the
-	 * right chats in the LocalDB.
-	 *
-	 * @since Envoy v0.1-alpha
-	 */
-	public void addUnreadMessagesToLocalDB() {
-		for (Message message : unreadMessagesSync.getMessages())
-			for (Chat chat : getChats())
-				if (message.getMetadata().getSender() == chat.getRecipient().getID()) {
-					chat.appendMessage(message);
-					break;
-				}
-	}
-
-	/**
-	 * Changes all messages with state {@code RECEIVED} of a specific chat to state
-	 * {@code READ}.
-	 * <br>
-	 * Adds these messages to the {@code readMessages} {@link Sync} object.
-	 *
-	 * @param currentChat the {@link Chat} that was just opened
-	 * @since Envoy v0.1-alpha
-	 */
-	public void setMessagesToRead(Chat currentChat) {
-		for (int i = currentChat.getModel().size() - 1; i >= 0; --i)
-			if (currentChat.getModel().get(i).getMetadata().getRecipient() != currentChat.getRecipient().getID())
-				if (currentChat.getModel().get(i).getMetadata().getState() == MessageState.RECEIVED) {
-					currentChat.getModel().get(i).getMetadata().setState(MessageState.READ);
-					readMessages.getMessages().add(currentChat.getModel().get(i));
-				} else break;
-	}
-
-	/**
-	 * Adds all messages with state {@code WAITING} from the {@link LocalDB} to the
-	 * {@link Sync} object.
-	 *
-	 * @since Envoy v0.1-alpha
-	 */
-	private void addWaitingMessagesToSync() {
-		for (Chat chat : getChats())
-			for (int i = 0; i < chat.getModel().size(); i++)
-				if (chat.getModel().get(i).getMetadata().getState() == MessageState.WAITING) {
-					logger.info("Got Waiting Message");
-					sync.getMessages().add(chat.getModel().get(i));
-				}
-	}
-
-	/**
-	 * Clears the {@code unreadMessagesSync} {@link Sync} object.
-	 *
-	 * @since Envoy v0.1-alpha
-	 */
-	public void clearUnreadMessagesSync() { unreadMessagesSync.getMessages().clear(); }
 
 	/**
 	 * @return a {@code Map<String, User>} of all users stored locally with their

src/main/java/envoy/client/ReceivedMessageProcessor.java

@@ -0,0 +1,32 @@
+package envoy.client;
+
+import java.util.function.Consumer;
+import java.util.logging.Logger;
+
+import envoy.client.event.MessageCreationEvent;
+import envoy.client.util.EnvoyLog;
+import envoy.data.Message;
+import envoy.data.Message.MessageStatus;
+import envoy.event.EventBus;
+
+/**
+ * Project: <strong>envoy-client</strong><br>
+ * File: <strong>ReceivedMessageProcessor.java</strong><br>
+ * Created: <strong>31.12.2019</strong><br>
+ * 
+ * @author Kai S. K. Engelbart
+ * @since Envoy v0.3-alpha
+ */
+public class ReceivedMessageProcessor implements Consumer<Message> {
+
+	private static final Logger logger = EnvoyLog.getLogger(ReceivedMessageProcessor.class.getSimpleName());
+
+	@Override
+	public void accept(Message message) {
+		logger.info("Received message object " + message);
+		if (message.getStatus() != MessageStatus.SENT) logger.warning("The message has the unexpected status " + message.getStatus());
+		else
+			// Dispatch event
+			EventBus.getInstance().dispatch(new MessageCreationEvent(message));
+	}
+}

src/main/java/envoy/client/Receiver.java

@@ -0,0 +1,86 @@
+package envoy.client;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.io.ObjectInputStream;
+import java.net.SocketException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Consumer;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import envoy.client.util.EnvoyLog;
+import envoy.util.SerializationUtils;
+
+/**
+ * Project: <strong>envoy-client</strong><br>
+ * File: <strong>Receiver.java</strong><br>
+ * Created: <strong>30.12.2019</strong><br>
+ *
+ * @author Kai S. K. Engelbart
+ * @since Envoy v0.3-alpha
+ */
+public class Receiver implements Runnable {
+
+	private final InputStream					in;
+	private final Map<Class<?>, Consumer<?>>	processors	= new HashMap<>();
+
+	private static final Logger logger = EnvoyLog.getLogger(Receiver.class.getSimpleName());
+
+	/**
+	 * Creates an instance of {@link Receiver}.
+	 *
+	 * @param in the {@link InputStream} to parse objects from
+	 */
+	public Receiver(InputStream in) { this.in = in; }
+
+	@SuppressWarnings("unchecked")
+	@Override
+	public void run() {
+
+		try {
+			while (true) {
+				// Read object length
+				byte[] lenBytes = new byte[4];
+				in.read(lenBytes);
+				int len = SerializationUtils.bytesToInt(lenBytes, 0);
+
+				// Read object into byte array
+				byte[] objBytes = new byte[len];
+				in.read(objBytes);
+
+				try (ObjectInputStream oin = new ObjectInputStream(new ByteArrayInputStream(objBytes))) {
+					Object obj = oin.readObject();
+					logger.finest("Received object " + obj);
+
+					// Get appropriate processor
+					@SuppressWarnings("rawtypes")
+					Consumer processor = processors.get(obj.getClass());
+					if (processor == null)
+						logger.severe(String.format("The received object has the class %s for which no processor is defined.", obj.getClass()));
+					else processor.accept(obj);
+				}
+			}
+		} catch (SocketException e) {
+			logger.info("Connection probably closed by client. Exiting receiver thread...");
+		} catch (Exception e) {
+			logger.log(Level.SEVERE, "Error on receiver thread", e);
+			e.printStackTrace();
+		}
+	}
+
+	/**
+	 * Adds an object processor to this {@link Receiver}. It will be called once an
+	 * object of the accepted class has been received.
+	 *
+	 * @param processorClass the object class accepted by the processor
+	 * @param processor      the object processor
+	 */
+	public <T> void registerProcessor(Class<T> processorClass, Consumer<T> processor) { processors.put(processorClass, processor); }
+
+	/**
+	 * Removes all object processors registered at this {@link Receiver}.
+	 */
+	public void removeAllProcessors() { processors.clear(); }
+}

src/main/java/envoy/client/Settings.java

@@ -1,14 +1,14 @@
 package envoy.client;
 
-import java.io.*;
+import java.io.File;
+import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.prefs.Preferences;
 
 import envoy.client.ui.Color;
 import envoy.client.ui.Theme;
-import envoy.client.util.SerializationUtils;
+import envoy.util.SerializationUtils;
-import envoy.exception.EnvoyException;
 
 /**
  * Manages all application settings, which are different objects that can be
@@ -55,7 +55,7 @@ public class Settings {
 		// Load settings from settings file
 		try {
 			items = SerializationUtils.read(settingsFile, HashMap.class);
-		} catch (EnvoyException e) {
+		} catch (ClassNotFoundException | IOException e) {
 			items = new HashMap<>();
 		}
 		supplementDefaults();
@@ -63,7 +63,7 @@ public class Settings {
 		// Load themes from theme file
 		try {
 			themes = SerializationUtils.read(themeFile, HashMap.class);
-		} catch (EnvoyException e1) {
+		} catch (ClassNotFoundException | IOException e1) {
 			themes = new HashMap<>();
 			setCurrentTheme("dark");
 		}

src/main/java/envoy/client/event/Event.java

@@ -1,19 +0,0 @@
-package envoy.client.event;
-
-/**
- * Project: <strong>envoy-client</strong><br>
- * File: <strong>Event.java</strong><br>
- * Created: <strong>04.12.2019</strong><br>
- *
- * @author Kai S. K. Engelbart
- * @param <T> the type of the Event
- * @since Envoy v0.2-alpha
- */
-public interface Event<T> {
-
-	/**
-	 * @return the data associated with this event
-	 */
-	T get();
-}
-

src/main/java/envoy/client/event/EventBus.java

@@ -1,81 +0,0 @@
-package envoy.client.event;
-
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
-/**
- * This class handles events by allowing {@link EventHandler} object to register
- * themselves and then be notified about certain events dispatched by the event
- * bus.<br>
- * <br>
- * The event bus is a singleton and can be used across the entire application to
- * guarantee the propagation of events.<br>
- *
- * Project: <strong>envoy-client</strong><br>
- * File: <strong>EventBus.java</strong><br>
- * Created: <strong>04.12.2019</strong><br>
- *
- * @author Kai S. K. Engelbart
- * @since Envoy v0.2-alpha
- */
-public class EventBus {
-
-	/**
-	 * Contains all {@link EventHandler} instances registered at this
-	 * {@link EventBus} as values mapped to by their supported {@link Event}
-	 * classes.
-	 */
-	private Map<Class<? extends Event<?>>, List<EventHandler>> handlers = new HashMap<>();
-
-	/**
-	 * The singleton instance of this {@link EventBus} that is used across the
-	 * entire application.
-	 */
-	private static EventBus eventBus = new EventBus();
-
-	/**
-	 * This constructor is not accessible from outside this class because a
-	 * singleton instance of it is provided by the {@link EventBus#getInstance()}
-	 * method.
-	 */
-	private EventBus() {}
-
-	/**
-	 * @return the singleton instance of the {@link EventBus}
-	 * @since Envoy v0.2-alpha
-	 */
-	public static EventBus getInstance() { return eventBus; }
-
-	/**
-	 * Registers an {@link EventHandler} to be notified when a
-	 * {@link Event} of a certain type is dispatched.
-	 *
-	 * @param eventClass the class which the {@link EventHandler} is subscribed to
-	 * @param handler    the {@link EventHandler} to register
-	 * @since Envoy v0.2-alpha
-	 */
-	public void register(Class<? extends Event<?>> eventClass, EventHandler handler) {
-		if (!handlers.containsKey(eventClass)) handlers.put(eventClass, new ArrayList<>());
-		handlers.get(eventClass).add(handler);
-	}
-
-	/**
-	 * Dispatches a {@link Event} to every {@link EventHandler} subscribed to it.
-	 *
-	 * @param event the {@link Event} to dispatch
-	 * @since Envoy v0.2-alpha
-	 */
-	public void dispatch(Event<?> event) {
-		handlers.keySet().stream().filter(event.getClass()::isAssignableFrom).map(handlers::get).flatMap(List::stream).forEach(h -> h.handle(event));
-	}
-
-	/**
-	 * @return a map of all {@link EventHandler} instances currently registered at
-	 *         this {@link EventBus} with the {@link Event} classes they are
-	 *         subscribed to as keys
-	 * @since Envoy v0.2-alpha
-	 */
-	public Map<Class<? extends Event<?>>, List<EventHandler>> getHandlers() { return handlers; }
-}

src/main/java/envoy/client/event/EventHandler.java

@@ -1,18 +0,0 @@
-package envoy.client.event;
-
-/**
- * Project: <strong>envoy-clientChess</strong><br>
- * File: <strong>EventHandler.javaEvent.java</strong><br>
- * Created: <strong>04.12.2019</strong><br>
- *
- * @author Kai S. K. Engelbart
- */
-public interface EventHandler {
-
-	/**
-	 * Consumes an event dispatched by the event bus.
-	 *
-	 * @param event The event dispatched by the event bus, only of supported type
-	 */
-	void handle(Event<?> event);
-}

src/main/java/envoy/client/event/MessageCreationEvent.java

@@ -1,6 +1,7 @@
 package envoy.client.event;
 
-import envoy.schema.Message;
+import envoy.data.Message;
+import envoy.event.MessageEvent;
 
 /**
  * Project: <strong>envoy-client</strong><br>

src/main/java/envoy/client/event/MessageEvent.java

@@ -1,27 +0,0 @@
-package envoy.client.event;
-
-import envoy.schema.Message;
-
-/**
- * Project: <strong>envoy-client</strong><br>
- * File: <strong>MessageCreationEvent.java</strong><br>
- * Created: <strong>4 Dec 2019</strong><br>
- *
- * @author Kai S. K. Engelbart
- */
-public class MessageEvent implements Event<Message> {
-
-	protected final Message message;
-
-	/**
-	 * Initializes a {@link MessageEvent} conveying information about a
-	 * {@link Message} object.
-	 *
-	 * @param message the {@link Message} object to attach to this event
-	 * @since Envoy v0.2-alpha
-	 */
-	public MessageEvent(Message message) { this.message = message; }
-
-	@Override
-	public Message get() { return message; }
-}

src/main/java/envoy/client/event/MessageModificationEvent.java

@@ -1,6 +1,7 @@
 package envoy.client.event;
 
-import envoy.schema.Message;
+import envoy.data.Message;
+import envoy.event.MessageEvent;
 
 /**
  * Project: <strong>envoy-client</strong><br>

src/main/java/envoy/client/event/ThemeChangeEvent.java

@@ -1,6 +1,7 @@
 package envoy.client.event;
 
 import envoy.client.ui.Theme;
+import envoy.event.Event;
 
 /**
  * Project: <strong>envoy-client</strong><br>

src/main/java/envoy/client/ui/ChatWindow.java

@@ -10,12 +10,13 @@ import javax.swing.*;
 import javax.swing.border.EmptyBorder;
 
 import envoy.client.*;
-import envoy.client.event.EventBus;
 import envoy.client.event.ThemeChangeEvent;
 import envoy.client.ui.settings.SettingsScreen;
 import envoy.client.util.EnvoyLog;
-import envoy.schema.Message;
+import envoy.data.Message;
-import envoy.schema.User;
+import envoy.data.MessageBuilder;
+import envoy.data.User;
+import envoy.event.EventBus;
 
 /**
  * Project: <strong>envoy-client</strong><br>
@@ -164,7 +165,7 @@ public class ChatWindow extends JFrame {
 				final JList<User>	selectedUserList	= (JList<User>) listSelectionEvent.getSource();
 				final User			user				= selectedUserList.getSelectedValue();
 
-				currentChat = localDB.getChats().stream().filter(chat -> chat.getRecipient().getID() == user.getID()).findFirst().get();
+				currentChat = localDB.getChats().stream().filter(chat -> chat.getRecipient().getId() == user.getId()).findFirst().get();
 
 				// Set all unread messages in the chat to read
 				readCurrentChat();
@@ -245,8 +246,15 @@ public class ChatWindow extends JFrame {
 
 		if (!messageEnterTextArea.getText().isEmpty()) try {
 
-			// Create and send message object
+			// Create message
-			final Message message = localDB.createMessage(messageEnterTextArea.getText(), currentChat.getRecipient().getID());
+			final Message message = new MessageBuilder(localDB.getUser().getId(), currentChat.getRecipient().getId())
+				.setText(messageEnterTextArea.getText())
+				.build();
+
+			// Send message
+			client.sendMessage(message);
+
+			// Add message to LocalDB and update UI
 			currentChat.appendMessage(message);
 			messageList.setModel(currentChat.getModel());
 
@@ -275,7 +283,7 @@ public class ChatWindow extends JFrame {
 				userListModel.addElement(user);
 
 				// Check if user exists in local DB
-				if (localDB.getChats().stream().filter(c -> c.getRecipient().getID() == user.getID()).count() == 0)
+				if (localDB.getChats().stream().filter(c -> c.getRecipient().getId() == user.getId()).count() == 0)
 					localDB.getChats().add(new Chat(user));
 			});
 			SwingUtilities.invokeLater(() -> userList.setModel(userListModel));
@@ -296,14 +304,15 @@ public class ChatWindow extends JFrame {
 
 				// Synchronize
 				try {
-					localDB.applySync(client.sendSync(client.getSender().getID(), localDB.fillSync(client.getSender().getID())));
+					// localDB.applySync(client.sendSync(client.getSender().getId(),
+					// localDB.fillSync(client.getSender().getId())));
 				} catch (Exception e) {
 					logger.log(Level.SEVERE, "Could not perform sync", e);
 				}
 
-				// Process unread messages
+				// TODO: Process unread messages
-				localDB.addUnreadMessagesToLocalDB();
+				// localDB.addUnreadMessagesToLocalDB();
-				localDB.clearUnreadMessagesSync();
+				// localDB.clearUnreadMessagesSync();
 
 				// Mark unread messages as read when they are in the current chat
 				readCurrentChat();
@@ -317,14 +326,18 @@ public class ChatWindow extends JFrame {
 	private void updateUserStates() {
 		for (int i = 0; i < userList.getModel().getSize(); i++)
 			for (int j = 0; j < localDB.getChats().size(); j++)
-				if (userList.getModel().getElementAt(i).getID() == localDB.getChats().get(j).getRecipient().getID())
+				if (userList.getModel().getElementAt(i).getId() == localDB.getChats().get(j).getRecipient().getId())
 					userList.getModel().getElementAt(i).setStatus(localDB.getChats().get(j).getRecipient().getStatus());
 	}
 
 	/**
 	 * Marks messages in the current chat as {@code READ}.
 	 */
-	private void readCurrentChat() { if (currentChat != null) { localDB.setMessagesToRead(currentChat); } }
+	private void readCurrentChat() {
+		if (currentChat != null) {
+			// TODO: localDB.setMessagesToRead(currentChat);
+		}
+	}
 
 	/**
 	 * Sets the {@link Client} used by this {@link ChatWindow}. If the client is

src/main/java/envoy/client/ui/LoginDialog.java

@@ -0,0 +1,118 @@
+package envoy.client.ui;
+
+import java.awt.*;
+import java.security.NoSuchAlgorithmException;
+
+import javax.swing.*;
+import javax.swing.border.EmptyBorder;
+
+import envoy.data.LoginCredentials;
+
+/**
+ * Project: <strong>envoy-client</strong><br>
+ * File: <strong>LoginDialog.java</strong><br>
+ * Created: <strong>01.01.2020</strong><br>
+ * 
+ * @author Kai S. K. Engelbart
+ * @since Envoy v0.3-alpha
+ */
+public class LoginDialog extends JDialog {
+
+	private final JPanel contentPanel = new JPanel();
+
+	private static final long	serialVersionUID	= 352021600833907468L;
+	private JTextField			textField;
+	private JPasswordField		passwordField;
+
+	private LoginCredentials credentials;
+
+	/**
+	 * Displays a dialog enabling the user to enter their user name and password.
+	 * 
+	 * @since Envoy v0.3-alpha
+	 */
+	public LoginDialog() {
+		setSize(338, 123);
+		setLocationRelativeTo(null);
+		getContentPane().setLayout(new BorderLayout());
+		contentPanel.setBorder(new EmptyBorder(5, 5, 5, 5));
+		getContentPane().add(contentPanel, BorderLayout.CENTER);
+		GridBagLayout gbl_contentPanel = new GridBagLayout();
+		gbl_contentPanel.columnWidths	= new int[] { 0, 0, 0 };
+		gbl_contentPanel.rowHeights		= new int[] { 0, 0, 0 };
+		gbl_contentPanel.columnWeights	= new double[] { 0.0, 1.0, Double.MIN_VALUE };
+		gbl_contentPanel.rowWeights		= new double[] { 0.0, 0.0, Double.MIN_VALUE };
+		contentPanel.setLayout(gbl_contentPanel);
+		{
+			JLabel				lblUserName		= new JLabel("User name:");
+			GridBagConstraints	gbc_lblUserName	= new GridBagConstraints();
+			gbc_lblUserName.anchor	= GridBagConstraints.EAST;
+			gbc_lblUserName.insets	= new Insets(0, 0, 5, 5);
+			gbc_lblUserName.gridx	= 0;
+			gbc_lblUserName.gridy	= 0;
+			contentPanel.add(lblUserName, gbc_lblUserName);
+		}
+		{
+			textField = new JTextField();
+			GridBagConstraints gbc_textField = new GridBagConstraints();
+			gbc_textField.insets	= new Insets(0, 0, 5, 0);
+			gbc_textField.fill		= GridBagConstraints.HORIZONTAL;
+			gbc_textField.gridx		= 1;
+			gbc_textField.gridy		= 0;
+			contentPanel.add(textField, gbc_textField);
+			textField.setColumns(10);
+		}
+		{
+			JLabel				lblPassword		= new JLabel("Password:");
+			GridBagConstraints	gbc_lblPassword	= new GridBagConstraints();
+			gbc_lblPassword.anchor	= GridBagConstraints.EAST;
+			gbc_lblPassword.insets	= new Insets(0, 0, 0, 5);
+			gbc_lblPassword.gridx	= 0;
+			gbc_lblPassword.gridy	= 1;
+			contentPanel.add(lblPassword, gbc_lblPassword);
+		}
+		{
+			passwordField = new JPasswordField();
+			GridBagConstraints gbc_passwordField = new GridBagConstraints();
+			gbc_passwordField.fill	= GridBagConstraints.HORIZONTAL;
+			gbc_passwordField.gridx	= 1;
+			gbc_passwordField.gridy	= 1;
+			contentPanel.add(passwordField, gbc_passwordField);
+		}
+		{
+			JPanel buttonPane = new JPanel();
+			buttonPane.setLayout(new FlowLayout(FlowLayout.RIGHT));
+			getContentPane().add(buttonPane, BorderLayout.SOUTH);
+			{
+				JButton okButton = new JButton("OK");
+				okButton.addActionListener((evt) -> {
+					try {
+						credentials = new LoginCredentials(textField.getText(), passwordField.getPassword());
+						dispose();
+					} catch (NoSuchAlgorithmException e) {
+						e.printStackTrace();
+					}
+				});
+				okButton.setActionCommand("OK");
+				buttonPane.add(okButton);
+				getRootPane().setDefaultButton(okButton);
+			}
+			{
+				JButton cancelButton = new JButton("Cancel");
+				cancelButton.addActionListener((evt) -> dispose());
+				cancelButton.setActionCommand("Cancel");
+				buttonPane.add(cancelButton);
+			}
+		}
+
+		setModal(true);
+		setVisible(true);
+	}
+
+	/**
+	 * @return the {@link LoginCredentials} entered by the user, or {@code null} if
+	 *         the dialog has been cancelled
+	 * @since Envoy v0.3-alpha
+	 */
+	public LoginCredentials getCredentials() { return credentials; }
+}

src/main/java/envoy/client/ui/MessageListRenderer.java

@@ -8,7 +8,7 @@ import javax.swing.JList;
 import javax.swing.ListCellRenderer;
 
 import envoy.client.Settings;
-import envoy.schema.Message;
+import envoy.data.Message;
 
 /**
  * Defines how a message is displayed.<br>
@@ -37,19 +37,17 @@ public class MessageListRenderer extends JLabel implements ListCellRenderer<Mess
 
 		setOpaque(true);
 
-		final String	text	= value.getContent().get(0).getText();
+		// TODO: Handle message attachments
-		final String	state	= value.getMetadata().getState().toString();
+
-		final String	date	= value.getMetadata().getDate() == null ? ""
+		final String	text	= value.getText();
-				: new SimpleDateFormat("dd.MM.yyyy HH:mm ").format(value.getMetadata().getDate().toGregorianCalendar().getTime());
+		final String	state	= value.getStatus().toString();
+		final String	date	= new SimpleDateFormat("dd.MM.yyyy HH.mm").format(value.getDate());
 
 		// Getting the MessageColor in the Chat of the current theme
-		String textColor = null;
+		String textColor = Settings.getInstance().getThemes().get(Settings.getInstance().getCurrentTheme()).getMessageColorChat().toHex();
-
-		textColor = Settings.getInstance().getThemes().get(Settings.getInstance().getCurrentTheme()).getMessageColorChat().toHex();
 
 		// Getting the DateColor in the Chat of the current theme
-		String dateColor = null;
+		String dateColor = Settings.getInstance().getThemes().get(Settings.getInstance().getCurrentTheme()).getDateColorChat().toHex();
-		dateColor = Settings.getInstance().getThemes().get(Settings.getInstance().getCurrentTheme()).getDateColorChat().toHex();
 
 		setText(String.format("<html><p style=\"color:%s\"><b><small>%s</b></small><br><p style=\"color:%s\">%s :%s</html>",
 				dateColor,

src/main/java/envoy/client/ui/Startup.java

@@ -2,6 +2,7 @@ package envoy.client.ui;
 
 import java.awt.EventQueue;
 import java.io.File;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -12,8 +13,9 @@ import javax.swing.SwingUtilities;
 
 import envoy.client.*;
 import envoy.client.util.EnvoyLog;
+import envoy.data.LoginCredentials;
+import envoy.data.User;
 import envoy.exception.EnvoyException;
-import envoy.schema.User;
 
 /**
  * Starts the Envoy client and prompts the user to enter their name.<br>
@@ -69,11 +71,12 @@ public class Startup {
 		EnvoyLog.setFileLevelBarrier(config.getFileLevelBarrier());
 		EnvoyLog.setConsoleLevelBarrier(config.getConsoleLevelBarrier());
 
-		// Ask the user for their user name
+		// Ask the user for their user name and password
-		String userName = JOptionPane.showInputDialog("Please enter your username");
+		LoginCredentials credentials = new LoginDialog().getCredentials();
-		if (userName == null || userName.isEmpty()) {
+
-			logger.severe("User name is not set or empty. Exiting...");
+		if (credentials == null) {
-			System.exit(1);
+			logger.info("The login process has been aborted by the user. Exiting...");
+			System.exit(0);
 		}
 
 		// Initialize the local database
@@ -91,20 +94,21 @@ public class Startup {
 
 		// Acquire the client user (with ID) either from the server or from the local
 		// database, which triggers offline mode
-		Client client = new Client(config);
+		Client client = new Client();
 		try {
 			// Try entering online mode first
-			client.onlineInit(userName);
+			client.onlineInit(credentials);
 		} catch (Exception e1) {
 			logger.warning("Could not connect to server. Trying offline mode...");
+			e1.printStackTrace();
 			try {
 				// Try entering offline mode
 				localDB.loadUsers();
-				User clientUser = localDB.getUsers().get(userName);
+				User clientUser = localDB.getUsers().get(credentials.getName());
 				if (clientUser == null) throw new EnvoyException("Could not enter offline mode: user name unknown");
 				client.setSender(clientUser);
 				JOptionPane.showMessageDialog(null,
-						"A connection to the server could not be established. Starting in offline mode.",
+						"A connection to the server could not be established. Starting in offline mode.\n" + e1,
 						"Connection error",
 						JOptionPane.WARNING_MESSAGE);
 			} catch (Exception e2) {
@@ -121,16 +125,16 @@ public class Startup {
 		try {
 			localDB.initializeDBFile();
 			localDB.loadChats();
-		} catch (EnvoyException e) {
+		} catch (FileNotFoundException e) {
+			// The local database file has not yet been created, probably first login
+		} catch (Exception e) {
 			e.printStackTrace();
 			JOptionPane.showMessageDialog(null,
-					"Error while loading local database: " + e.toString() + "\nChats will not be stored locally.",
+					"Error while loading local database: " + e + "\nChats might not be stored locally.",
 					"Local DB error",
 					JOptionPane.WARNING_MESSAGE);
 		}
 
-		logger.info("Client user ID: " + client.getSender().getID());
-
 		// Save all users to the local database
 		if (client.isOnline()) localDB.setUsers(client.getUsers());
 
@@ -142,8 +146,13 @@ public class Startup {
 				try {
 					new StatusTrayIcon(chatWindow).show();
 
-					// If the tray icon is supported and corresponding settings is set, hide the chat window on close
+					// If the tray icon is supported and corresponding settings is set, hide the
-					Settings.getInstance().getItems().get("onCloseMode").setChangeHandler((onCloseMode) -> chatWindow.setDefaultCloseOperation((boolean) onCloseMode ? JFrame.HIDE_ON_CLOSE : JFrame.EXIT_ON_CLOSE)); 
+					// chat window on close
+					Settings.getInstance()
+						.getItems()
+						.get("onCloseMode")
+						.setChangeHandler((onCloseMode) -> chatWindow
+							.setDefaultCloseOperation((boolean) onCloseMode ? JFrame.HIDE_ON_CLOSE : JFrame.EXIT_ON_CLOSE));
 				} catch (EnvoyException e) {
 					logger.warning("The StatusTrayIcon is not supported on this platform!");
 				}
@@ -155,13 +164,14 @@ public class Startup {
 		// Save Settings and LocalDB on shutdown
 		Runtime.getRuntime().addShutdownHook(new Thread(() -> {
 			try {
-				logger.info("Saving local database...");
+				logger.info("Closing connection...");
+				client.close();
+
+				logger.info("Saving local database and settings...");
 				localDB.save();
-				logger.info("Saving settings...");
 				Settings.getInstance().save();
-			} catch (IOException e1) {
+			} catch (IOException e) {
-				e1.printStackTrace();
+				logger.log(Level.SEVERE, "Unable to save local files", e);
-				logger.log(Level.WARNING, "Unable to save the messages", e1);
 			}
 		}));
 	}

src/main/java/envoy/client/ui/StatusTrayIcon.java

@@ -1,21 +1,14 @@
 package envoy.client.ui;
 
-import java.awt.AWTException;
+import java.awt.*;
-import java.awt.Image;
-import java.awt.MenuItem;
-import java.awt.PopupMenu;
-import java.awt.SystemTray;
-import java.awt.Toolkit;
-import java.awt.TrayIcon;
 import java.awt.TrayIcon.MessageType;
-import java.awt.Window;
 import java.awt.event.WindowAdapter;
 import java.awt.event.WindowEvent;
 
-import envoy.client.event.EventBus;
 import envoy.client.event.MessageCreationEvent;
+import envoy.data.Message;
+import envoy.event.EventBus;
 import envoy.exception.EnvoyException;
-import envoy.schema.Message;
 
 /**
  * Project: <strong>envoy-client</strong><br>
@@ -81,10 +74,13 @@ public class StatusTrayIcon {
 		trayIcon.addActionListener((evt) -> { focusTarget.setVisible(true); focusTarget.requestFocus(); });
 
 		// Start processing message events
-		EventBus.getInstance().register(MessageCreationEvent.class, (evt) -> {
+		EventBus.getInstance()
-			if (displayMessages)
+			.register(MessageCreationEvent.class,
-				trayIcon.displayMessage("New message received", ((MessageCreationEvent) evt).get().getContent().get(0).getText(), MessageType.INFO);
+					(evt) -> {
-		});
+						// TODO: Handle other message types
+						if (displayMessages)
+							trayIcon.displayMessage("New message received", ((MessageCreationEvent) evt).get().getText(), MessageType.INFO);
+					});
 	}
 
 	/**

src/main/java/envoy/client/ui/UserListRenderer.java

@@ -7,8 +7,8 @@ import javax.swing.JList;
 import javax.swing.ListCellRenderer;
 
 import envoy.client.Settings;
-import envoy.schema.User;
+import envoy.data.User;
-import envoy.schema.User.UserStatus;
+import envoy.data.User.UserStatus;
 
 /**
  * Defines how the {@code UserList} is displayed.<br>

src/main/java/envoy/client/ui/settings/SettingsScreen.java

@@ -10,11 +10,11 @@ import java.util.logging.Logger;
 import javax.swing.*;
 
 import envoy.client.Settings;
-import envoy.client.event.EventBus;
 import envoy.client.event.ThemeChangeEvent;
 import envoy.client.ui.PrimaryButton;
 import envoy.client.ui.Theme;
 import envoy.client.util.EnvoyLog;
+import envoy.event.EventBus;
 
 /**
  * This class provides the GUI to change the user specific settings.<br>

src/main/java/envoy/client/ui/settings/ThemeCustomizationPanel.java

@@ -10,11 +10,11 @@ import java.util.logging.Logger;
 import javax.swing.*;
 
 import envoy.client.Settings;
-import envoy.client.event.EventBus;
 import envoy.client.event.ThemeChangeEvent;
 import envoy.client.ui.Color;
 import envoy.client.ui.Theme;
 import envoy.client.util.EnvoyLog;
+import envoy.event.EventBus;
 
 /**
  * Displays GUI components that allow changing the current {@Theme} and creating

src/main/java/envoy/client/util/SerializationUtils.java

@@ -1,57 +0,0 @@
-package envoy.client.util;
-
-import java.io.*;
-
-import envoy.exception.EnvoyException;
-
-/**
- * Project: <strong>envoy-clientChess</strong><br>
- * File: <strong>SerializationUtils.javaEvent.java</strong><br>
- * Created: <strong>23.12.2019</strong><br>
- * 
- * @author Kai S. K. Engelbart
- * @since Envoy v0.3-alpha
- */
-public class SerializationUtils {
-
-	private SerializationUtils() {}
-
-	/**
-	 * Deserializes an arbitrary {@link Serializable} object from a file.
-	 * 
-	 * @param <T>             the type of the object to deserialize
-	 * @param file            the file deserialize from
-	 * @param serializedClass the class of the object to deserialize
-	 * @return the deserialized object
-	 * @throws EnvoyException if an error occurred during deserialization
-	 * @since Envoy v0.3-alpha
-	 */
-	public static <T extends Serializable> T read(File file, Class<T> serializedClass) throws EnvoyException {
-		if (file == null) throw new NullPointerException("File is null");
-		try (ObjectInputStream in = new ObjectInputStream(new FileInputStream(file))) {
-			return serializedClass.cast(in.readObject());
-		} catch (ClassNotFoundException | IOException e) {
-			throw new EnvoyException("Could not load serialized object", e);
-		}
-	}
-
-	/**
-	 * Serializes an arbitrary object to a file.
-	 * 
-	 * @param file the file to serialize to
-	 * @param obj  the object to serialize
-	 * @throws IOException if an error occurred during serialization
-	 * @since Envoy v0.3-alpha
-	 */
-	public static void write(File file, Object obj) throws IOException {
-		if (file == null) throw new NullPointerException("File is null");
-		if (obj == null) throw new NullPointerException("Object to serialize is null");
-		if (!file.exists()) {
-			file.getParentFile().mkdirs();
-			file.createNewFile();
-		}
-		try (ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(file))) {
-			out.writeObject(obj);
-		}
-	}
-}