Merge branch 'develop' into f/groupMessages

Conflicts:
	src/main/java/envoy/client/ui/controller/ChatScene.java

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @CyB3RC0nN0R

README.md

@@ -1,6 +1,6 @@
 # Envoy Client
 
-<a href="https://github.com/informatik-ag-ngl/envoy-client"><img src="https://raw.githubusercontent.com/informatik-ag-ngl/envoy-client/develop/src/main/resources/envoy_logo.png" align="left" width="200" height="200"></a>
+<a href="https://github.com/informatik-ag-ngl/envoy-client"><img src="https://raw.githubusercontent.com/informatik-ag-ngl/envoy-client/develop/src/main/resources/icons/envoy_logo.png" align="left" width="200" height="200"></a>
 
 **Envoy Client** is one of two repositories needed to use the messenger Envoy.<br>
 The other one is <a href="https://github.com/informatik-ag-ngl/envoy-common">**Envoy Common**</a>.

src/main/java/envoy/client/data/Cache.java

@@ -4,13 +4,14 @@ import java.io.Serializable;
 import java.util.LinkedList;
 import java.util.Queue;
 import java.util.function.Consumer;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import envoy.util.EnvoyLog;
 
 /**
- * Stores elements in a queue to process them later.<br>
+ * Stores elements in a queue to process them later.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>Cache.java</strong><br>
  * Created: <strong>6 Feb 2020</strong><br>
@@ -35,10 +36,13 @@ public class Cache<T> implements Consumer<T>, Serializable {
 	 */
 	@Override
 	public void accept(T element) {
-		logger.fine(String.format("Adding element %s to cache", element));
+		logger.log(Level.FINE, String.format("Adding element %s to cache", element));
 		elements.offer(element);
 	}
 
+	@Override
+	public String toString() { return String.format("Cache[elements=" + elements + "]"); }
+
 	/**
 	 * Sets the processor to which cached elements are relayed.
 	 *

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

@@ -4,16 +4,17 @@ import java.io.IOException;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 import envoy.client.net.WriteProxy;
 import envoy.data.*;
 import envoy.data.Message.MessageStatus;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 
 /**
- * Represents a chat between two {@link User}s <br>
+ * Represents a chat between two {@link User}s
  * as a list of {@link Message} objects.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>Chat.java</strong><br>
  * Created: <strong>19 Oct 2019</strong><br>
@@ -31,7 +32,7 @@ public final class Chat implements Serializable {
 	private static final long serialVersionUID = 1L;
 
 	/**
-	 * Provides the list of messages that the recipient receives.<br>
+	 * Provides the list of messages that the recipient receives.<p>
 	 * Saves the Messages in the corresponding chat at that Point.
 	 *
 	 * @param recipient the user who receives the messages
@@ -42,6 +43,27 @@ public final class Chat implements Serializable {
 	@Override
 	public String toString() { return String.format("Chat[recipient=%s,messages=%d]", recipient, messages.size()); }
 
+	/**
+	 * Generates a hash code based on the recipient.
+	 * 
+	 * @since Envoy Client v0.1-beta
+	 */
+	@Override
+	public int hashCode() { return Objects.hash(recipient); }
+
+	/**
+	 * Tests equality to another object based on the recipient.
+	 * 
+	 * @since Envoy Client v0.1-beta
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) return true;
+		if (!(obj instanceof Chat)) return false;
+		Chat other = (Chat) obj;
+		return Objects.equals(recipient, other.recipient);
+	}
+
 	/**
 	 * Sets the status of all chat messages received from the recipient to
 	 * {@code READ} starting from the bottom and stopping once a read message is
@@ -49,7 +71,7 @@ public final class Chat implements Serializable {
 	 *
 	 * @param writeProxy the write proxy instance used to notify the server about
 	 *                   the message status changes
-	 * @throws IOException if a {@link MessageStatusChangeEvent} could not be
+	 * @throws IOException if a {@link MessageStatusChange} could not be
 	 *                     delivered to the server
 	 * @since Envoy Client v0.3-alpha
 	 */
@@ -59,7 +81,7 @@ public final class Chat implements Serializable {
 			if (m.getSenderID() == recipient.getID()) if (m.getStatus() == MessageStatus.READ) break;
 			else {
 				m.setStatus(MessageStatus.READ);
-				writeProxy.writeMessageStatusChangeEvent(new MessageStatusChangeEvent(m));
+				writeProxy.writeMessageStatusChange(new MessageStatusChange(m));
 			}
 		}
 	}

src/main/java/envoy/client/data/ClientConfig.java

@@ -4,14 +4,15 @@ import java.io.File;
 import java.util.function.Function;
 import java.util.logging.Level;
 
+import envoy.client.ui.Startup;
 import envoy.data.Config;
 import envoy.data.ConfigItem;
 import envoy.data.LoginCredentials;
 
 /**
  * Implements a configuration specific to the Envoy Client with default values
- * and convenience methods.<br>
+ * and convenience methods.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>ClientConfig.java</strong><br>
  * Created: <strong>01.03.2020</strong><br>
@@ -109,5 +110,5 @@ public class ClientConfig extends Config {
 	 *         the registration option
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public LoginCredentials getLoginCredentials() { return new LoginCredentials(getUser(), getPassword(), false); }
+	public LoginCredentials getLoginCredentials() { return new LoginCredentials(getUser(), getPassword(), false, Startup.VERSION); }
 }

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

@@ -3,14 +3,14 @@ package envoy.client.data;
 import java.util.*;
 
 import envoy.data.*;
-import envoy.event.GroupResizeEvent;
+import envoy.event.GroupResize;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
-import envoy.event.NameChangeEvent;
+import envoy.event.NameChange;
 
 /**
  * Stores information about the current {@link User} and their {@link Chat}s.
- * For message ID generation a {@link IDGenerator} is stored as well.<br>
+ * For message ID generation a {@link IDGenerator} is stored as well.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>LocalDB.java</strong><br>
  * Created: <strong>3 Feb 2020</strong><br>
@@ -25,7 +25,7 @@ public abstract class LocalDB {
 	protected List<Chat>					chats			= new ArrayList<>();
 	protected IDGenerator					idGenerator;
 	protected Cache<Message>				messageCache	= new Cache<>();
-	protected Cache<MessageStatusChangeEvent>	statusCache		= new Cache<>();
+	protected Cache<MessageStatusChange>	statusCache		= new Cache<>();
 
 	/**
 	 * Initializes a storage space for a user-specific list of chats.
@@ -66,6 +66,25 @@ public abstract class LocalDB {
 	 */
 	public void loadIDGenerator() {}
 
+	/**
+	 * Synchronizes the contact list of the client user with the chat and user
+	 * storage.
+	 * 
+	 * @since Envoy Client v0.1-beta
+	 */
+	public void synchronize() {
+		user.getContacts().stream().filter(u -> u instanceof User && !users.containsKey(u.getName())).forEach(u -> users.put(u.getName(), u));
+		users.put(user.getName(), user);
+
+		// Synchronize user status data
+		for (Contact contact : users.values())
+			if (contact instanceof User)
+				getChat(contact.getID()).ifPresent(chat -> { ((User) chat.getRecipient()).setStatus(((User) contact).getStatus()); });
+
+		// Create missing chats
+		user.getContacts().stream().filter(u -> !u.equals(user) && getChat(u.getID()).isEmpty()).map(Chat::new).forEach(chats::add);
+	}
+
 	/**
 	 * @return a {@code Map<String, User>} of all users stored locally with their
 	 *         user names as keys
@@ -73,11 +92,6 @@ public abstract class LocalDB {
 	 */
 	public Map<String, Contact> getUsers() { return users; }
 
-	/**
-	 * @param users the users to set
-	 */
-	public void setUsers(Map<String, Contact> users) { this.users = users; }
-
 	/**
 	 * @return all saved {@link Chat} objects that list the client user as the
 	 *         sender
@@ -136,13 +150,13 @@ public abstract class LocalDB {
 	 * @return the offline status cache
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public Cache<MessageStatusChangeEvent> getStatusCache() { return statusCache; }
+	public Cache<MessageStatusChange> getStatusCache() { return statusCache; }
 
 	/**
 	 * @param statusCache the offline status cache to set
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public void setStatusCache(Cache<MessageStatusChangeEvent> statusCache) { this.statusCache = statusCache; }
+	public void setStatusCache(Cache<MessageStatusChange> statusCache) { this.statusCache = statusCache; }
 
 	/**
 	 * Searches for a message by ID.
@@ -162,27 +176,25 @@ public abstract class LocalDB {
 	 * @return an optional containing the chat
 	 * @since Envoy Client v0.1-beta
 	 */
-	public Optional<Chat> getChat(long recipientID) {
+	public Optional<Chat> getChat(long recipientID) { return chats.stream().filter(c -> c.getRecipient().getID() == recipientID).findAny(); }
-		return chats.stream().filter(c -> c.getRecipient().getID() == recipientID).findAny();
-	}
 
 	/**
 	 * Performs a contact name change if the corresponding contact is present.
 	 *
-	 * @param event the {@link NameChangeEvent} to process
+	 * @param event the {@link NameChange} to process
 	 * @since Envoy Client v0.1-beta
 	 */
-	public void replaceContactName(NameChangeEvent event) {
+	public void replaceContactName(NameChange event) {
 		chats.stream().map(Chat::getRecipient).filter(c -> c.getID() == event.getID()).findAny().ifPresent(c -> c.setName(event.get()));
 	}
 
 	/**
 	 * Performs a group resize operation if the corresponding group is present.
 	 *
-	 * @param event the {@link GroupResizeEvent} to process
+	 * @param event the {@link GroupResize} to process
 	 * @since Envoy Client v0.1-beta
 	 */
-	public void updateGroup(GroupResizeEvent event) {
+	public void updateGroup(GroupResize event) {
 		chats.stream()
 			.map(Chat::getRecipient)
 			.filter(Group.class::isInstance)
@@ -200,13 +212,4 @@ public abstract class LocalDB {
 				}
 			});
 	}
-	
-	/**
-	 * Creates a new {@link Chat} for all {@link Contact}s that do not have a chat.
-	 * 
-	 * @since Envoy Client v0.1-beta
-	 */
-	public void createMissingChats() {
-		users.values().stream().filter(u -> !u.equals(user) && getChat(u.getID()).isEmpty()).map(Chat::new).forEach(chats::add);
-	}
 }

src/main/java/envoy/client/data/PersistentLocalDB.java

@@ -1,18 +1,18 @@
 package envoy.client.data;
 
-import java.io.File;
+import java.io.*;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
 
-import envoy.data.ConfigItem;
 import envoy.data.IDGenerator;
+import envoy.data.Message;
+import envoy.event.MessageStatusChange;
 import envoy.util.SerializationUtils;
 
 /**
  * Implements a {@link LocalDB} in a way that stores all information inside a
- * folder on the local file system.<br>
+ * folder on the local file system.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>PersistentLocalDB.java</strong><br>
  * Created: <strong>27.10.2019</strong><br>
@@ -21,92 +21,67 @@ import envoy.util.SerializationUtils;
  * @author Maximilian K&auml;fer
  * @since Envoy Client v0.1-alpha
  */
-public class PersistentLocalDB extends LocalDB {
+public final class PersistentLocalDB extends LocalDB {
 
-	private File localDBDir, localDBFile, usersFile, idGeneratorFile, messageCacheFile, statusCacheFile;
+	private File dbDir, userFile, idGeneratorFile, usersFile;
 
 	/**
-	 * Initializes an empty local database without a directory. All changes made to
+	 * Constructs an empty local database. To serialize any user-specific data to
-	 * this instance cannot be saved to the file system.<br>
+	 * the file system, call {@link PersistentLocalDB#initializeUserStorage()} first
-	 * <br>
+	 * and then {@link PersistentLocalDB#save()}.
-	 * This constructor shall be used in conjunction with the {@code ignoreLocalDB}
-	 * {@link ConfigItem}.
 	 *
-	 * @since Envoy Client v0.3-alpha
+	 * @param dbDir the directory in which to persist data
-	 */
+	 * @throws IOException if {@code dbDir} is a file (and not a directory)
-	public PersistentLocalDB() {}
-
-	/**
-	 * Constructs an empty local database. To serialize any chats to the file
-	 * system, call {@link PersistentLocalDB#initializeUserStorage()}.
-	 *
-	 * @param localDBDir the directory in which to store users and chats
-	 * @throws IOException if the PersistentLocalDB could not be initialized
 	 * @since Envoy Client v0.1-alpha
 	 */
-	public PersistentLocalDB(File localDBDir) throws IOException {
+	public PersistentLocalDB(File dbDir) throws IOException {
-		this.localDBDir = localDBDir;
+		this.dbDir = dbDir;
 
-		// Initialize local database directory
+		// Test if the database directory is actually a directory
-		if (localDBDir.exists() && !localDBDir.isDirectory())
+		if (dbDir.exists() && !dbDir.isDirectory())
-			throw new IOException(String.format("LocalDBDir '%s' is not a directory!", localDBDir.getAbsolutePath()));
+			throw new IOException(String.format("LocalDBDir '%s' is not a directory!", dbDir.getAbsolutePath()));
-		usersFile		= new File(localDBDir, "users.db");
+
-		idGeneratorFile	= new File(localDBDir, "id_generator.db");
+		// Initialize global files
+		idGeneratorFile	= new File(dbDir, "id_gen.db");
+		usersFile		= new File(dbDir, "users.db");
 	}
 
 	/**
-	 * Creates a database file for a user-specific list of chats.<br>
+	 * Creates a database file for a user-specific list of chats.
-	 * {@inheritDoc}
 	 *
-	 * @throws NullPointerException if the client user is not yet specified
+	 * @throws IllegalStateException if the client user is not specified
 	 * @since Envoy Client v0.1-alpha
 	 */
 	@Override
 	public void initializeUserStorage() {
-		if (user == null) throw new NullPointerException("Client user is null");
+		if (user == null) throw new IllegalStateException("Client user is null, cannot initialize user storage");
-		localDBFile			= new File(localDBDir, user.getID() + ".db");
+		userFile = new File(dbDir, user.getID() + ".db");
-		messageCacheFile	= new File(localDBDir, user.getID() + "_message_cache.db");
-		statusCacheFile		= new File(localDBDir, user.getID() + "_status_cache.db");
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public void save() throws IOException {
 		// Save users
 		SerializationUtils.write(usersFile, users);
 
 		// Save user data
-		if (user != null) {
+		if (user != null) SerializationUtils.write(userFile, chats, messageCache, statusCache);
-			SerializationUtils.write(localDBFile, chats);
-			SerializationUtils.write(messageCacheFile, messageCache);
-			SerializationUtils.write(statusCacheFile, statusCache);
-		}
 
 		// Save id generator
 		if (hasIDGenerator()) SerializationUtils.write(idGeneratorFile, idGenerator);
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public void loadUsers() throws ClassNotFoundException, IOException { users = SerializationUtils.read(usersFile, HashMap.class); }
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public void loadUserData() throws ClassNotFoundException, IOException {
-		chats			= SerializationUtils.read(localDBFile, ArrayList.class);
+		try (var in = new ObjectInputStream(new FileInputStream(userFile))) {
-		messageCache	= SerializationUtils.read(messageCacheFile, Cache.class);
+			chats = (ArrayList<Chat>) in.readObject();
-		statusCache		= SerializationUtils.read(statusCacheFile, Cache.class);
+			messageCache	= (Cache<Message>) in.readObject();
+			statusCache		= (Cache<MessageStatusChange>) in.readObject();
+		}
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public void loadIDGenerator() {
 		try {

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

@@ -11,8 +11,8 @@ import envoy.util.SerializationUtils;
 /**
  * Manages all application settings, which are different objects that can be
  * changed during runtime and serialized them by using either the file system or
- * the {@link Preferences} API.<br>
+ * the {@link Preferences} API.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>Settings.java</strong><br>
  * Created: <strong>11 Nov 2019</strong><br>

src/main/java/envoy/client/data/SettingsItem.java

@@ -7,8 +7,8 @@ import javax.swing.JComponent;
 
 /**
  * Encapsulates a persistent value that is directly or indirectly mutable by the
- * user.<br>
+ * user.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>SettingsItem.java</strong><br>
  * Created: <strong>23.12.2019</strong><br>

src/main/java/envoy/client/data/TransientLocalDB.java

@@ -2,8 +2,8 @@ package envoy.client.data;
 
 /**
  * Implements a {@link LocalDB} in a way that does not persist any information
- * after application shutdown.<br>
+ * after application shutdown.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>TransientLocalDB.java</strong><br>
  * Created: <strong>3 Feb 2020</strong><br>
@@ -11,5 +11,5 @@ package envoy.client.data;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class TransientLocalDB extends LocalDB {
+public final class TransientLocalDB extends LocalDB {
 }

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

@@ -8,7 +8,6 @@ import envoy.event.Event;
  * Created: <strong>11.02.2020</strong><br>
  *
  * @author: Maximilian K&aumlfer
- *
  * @since Envoy Client v0.3-alpha
  */
 public class SendEvent extends Event<Event<?>> {

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

@@ -3,10 +3,8 @@ package envoy.client.net;
 import java.io.Closeable;
 import java.io.IOException;
 import java.net.Socket;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.TimeoutException;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import envoy.client.data.Cache;
@@ -15,15 +13,15 @@ import envoy.client.data.LocalDB;
 import envoy.client.event.SendEvent;
 import envoy.data.*;
 import envoy.event.*;
-import envoy.event.contact.ContactOperationEvent;
+import envoy.event.contact.ContactOperation;
 import envoy.event.contact.ContactSearchResult;
 import envoy.util.EnvoyLog;
 import envoy.util.SerializationUtils;
 
 /**
  * Establishes a connection to the server, performs a handshake and delivers
- * certain objects to the server.<br>
+ * certain objects to the server.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>Client.java</strong><br>
  * Created: <strong>28 Sep 2019</strong><br>
@@ -42,7 +40,6 @@ public class Client implements Closeable {
 
 	// Asynchronously initialized during handshake
 	private volatile User		sender;
-	private volatile Set<? extends Contact>	contacts;
 	private volatile boolean	rejected;
 
 	// Configuration, logging and event management
@@ -57,33 +54,37 @@ public class Client implements Closeable {
 	 * an exception is thrown.
 	 *
 	 * @param credentials                      the login credentials of the user
-	 * @param receivedMessageCache a message cache containing all unread messages
+	 * @param receivedMessageCache             a message cache containing all unread
-	 *                             from the server that can be relayed after
+	 *                                         messages
+	 *                                         from the server that can be relayed
+	 *                                         after
 	 *                                         initialization
-	 * @param receivedMessageStatusChangeEventCache an event cache containing all received messageStatusChangeEvents from the server that can be relayed after initialization
+	 * @param receivedMessageStatusChangeCache an event cache containing all
+	 *                                         received messageStatusChangeEvents
+	 *                                         from the server that can be relayed
+	 *                                         after initialization
 	 * @throws TimeoutException     if the server could not be reached
-	 * @throws IOException          if the login credentials could not be
+	 * @throws IOException          if the login credentials could not be written
-	 *                              written
 	 * @throws InterruptedException if the current thread is interrupted while
 	 *                              waiting for the handshake response
 	 */
 	public void performHandshake(LoginCredentials credentials, Cache<Message> receivedMessageCache,
-			Cache<MessageStatusChangeEvent> receivedMessageStatusChangeEventCache)
+			Cache<MessageStatusChange> receivedMessageStatusChangeCache) throws TimeoutException, IOException, InterruptedException {
-			throws TimeoutException, IOException, InterruptedException {
 		if (online) throw new IllegalStateException("Handshake has already been performed successfully");
+
 		// Establish TCP connection
-		logger.finer(String.format("Attempting connection to server %s:%d...", config.getServer(), config.getPort()));
+		logger.log(Level.FINER, String.format("Attempting connection to server %s:%d...", config.getServer(), config.getPort()));
 		socket = new Socket(config.getServer(), config.getPort());
-		logger.fine("Successfully established TCP connection to server");
+		logger.log(Level.FINE, "Successfully established TCP connection to server");
 
 		// Create object receiver
 		receiver = new Receiver(socket.getInputStream());
 
 		// Register user creation processor, contact list processor and message cache
-		receiver.registerProcessor(User.class, sender -> { this.sender = sender; contacts = sender.getContacts(); });
+		receiver.registerProcessor(User.class, sender -> this.sender = sender);
 		receiver.registerProcessor(Message.class, receivedMessageCache);
-		receiver.registerProcessor(MessageStatusChangeEvent.class, receivedMessageStatusChangeEventCache);
+		receiver.registerProcessor(MessageStatusChange.class, receivedMessageStatusChangeCache);
-		receiver.registerProcessor(HandshakeRejectionEvent.class, evt -> { rejected = true; eventBus.dispatch(evt); });
+		receiver.registerProcessor(HandshakeRejection.class, evt -> { rejected = true; eventBus.dispatch(evt); });
 
 		rejected = false;
 
@@ -114,30 +115,36 @@ public class Client implements Closeable {
 		// Remove all processors as they are only used during the handshake
 		receiver.removeAllProcessors();
 
-		logger.info("Handshake completed.");
+		logger.log(Level.INFO, "Handshake completed.");
 	}
 
 	/**
 	 * Initializes the {@link Receiver} used to process data sent from the server to
 	 * this client.
 	 *
-	 * @param localDB              the local database used to persist the current
+	 * @param localDB                          the local database used to persist
+	 *                                         the current
 	 *                                         {@link IDGenerator}
-	 * @param receivedMessageCache a message cache containing all unread messages
+	 * @param receivedMessageCache             a message cache containing all unread
-	 *                             from the server that can be relayed after
+	 *                                         messages
+	 *                                         from the server that can be relayed
+	 *                                         after
 	 *                                         initialization
-	 * @param receivedMessageStatusChangeEventCache an event cache containing all received messageStatusChangeEvents from the server that can be relayed after initialization
+	 * @param receivedMessageStatusChangeCache an event cache containing all
+	 *                                         received messageStatusChangeEvents
+	 *                                         from the server that can be relayed
+	 *                                         after initialization
 	 * @throws IOException if no {@link IDGenerator} is present and none could be
 	 *                     requested from the server
 	 * @since Envoy Client v0.2-alpha
 	 */
-	public void initReceiver(LocalDB localDB, Cache<Message> receivedMessageCache,
+	public void initReceiver(LocalDB localDB, Cache<Message> receivedMessageCache, Cache<MessageStatusChange> receivedMessageStatusChangeCache)
-			Cache<MessageStatusChangeEvent> receivedMessageStatusChangeEventCache) throws IOException {
+			throws IOException {
 		checkOnline();
 
 		// Process incoming messages
 		final ReceivedMessageProcessor		receivedMessageProcessor			= new ReceivedMessageProcessor();
-		final MessageStatusChangeEventProcessor	messageStatusChangeEventProcessor	= new MessageStatusChangeEventProcessor();
+		final MessageStatusChangeProcessor	messageStatusChangeEventProcessor	= new MessageStatusChangeProcessor();
 
 		// TODO: Define a cache
 		receiver.registerProcessor(GroupMessage.class, new ReceivedGroupMessageProcessor());
@@ -148,33 +155,33 @@ public class Client implements Closeable {
 		receivedMessageCache.setProcessor(receivedMessageProcessor);
 
 		// Process message status changes
-		receiver.registerProcessor(MessageStatusChangeEvent.class, messageStatusChangeEventProcessor);
+		receiver.registerProcessor(MessageStatusChange.class, messageStatusChangeEventProcessor);
-		receivedMessageStatusChangeEventCache.setProcessor(messageStatusChangeEventProcessor);
+		receivedMessageStatusChangeCache.setProcessor(messageStatusChangeEventProcessor);
 
 		// Process user status changes
-		receiver.registerProcessor(UserStatusChangeEvent.class, eventBus::dispatch);
+		receiver.registerProcessor(UserStatusChange.class, eventBus::dispatch);
 
 		// Process message ID generation
 		receiver.registerProcessor(IDGenerator.class, localDB::setIDGenerator);
 
 		// Process name changes
-		receiver.registerProcessor(NameChangeEvent.class, evt -> { localDB.replaceContactName(evt); eventBus.dispatch(evt); });
+		receiver.registerProcessor(NameChange.class, evt -> { localDB.replaceContactName(evt); eventBus.dispatch(evt); });
 
 		// Process contact searches
 		receiver.registerProcessor(ContactSearchResult.class, eventBus::dispatch);
 
 		// Process contact operations
-		receiver.registerProcessor(ContactOperationEvent.class, eventBus::dispatch);
+		receiver.registerProcessor(ContactOperation.class, eventBus::dispatch);
 
 		// Process group size changes
-		receiver.registerProcessor(GroupResizeEvent.class, evt -> { localDB.updateGroup(evt); eventBus.dispatch(evt); });
+		receiver.registerProcessor(GroupResize.class, evt -> { localDB.updateGroup(evt); eventBus.dispatch(evt); });
 
 		// Send event
 		eventBus.register(SendEvent.class, evt -> {
 			try {
 				sendEvent(evt.get());
 			} catch (final IOException e) {
-				e.printStackTrace();
+				logger.log(Level.WARNING, "An error occurred when trying to send " + evt, e);
 			}
 		});
 
@@ -221,36 +228,23 @@ public class Client implements Closeable {
 	 * @since Envoy Client v0.3-alpha
 	 */
 	public void requestIdGenerator() throws IOException {
-		logger.info("Requesting new id generator...");
+		logger.log(Level.INFO, "Requesting new id generator...");
 		writeObject(new IDGeneratorRequest());
 	}
 
-	/**
-	 * @return a {@code Map<String, User>} of all users on the server with their
-	 *         user names as keys
-	 * @since Envoy Client v0.2-alpha
-	 */
-	public Map<String, Contact> getUsers() {
-		checkOnline();
-		final Map<String, Contact> users = new HashMap<>();
-		contacts.forEach(u -> users.put(u.getName(), u));
-		users.put(sender.getName(), sender);
-		return users;
-	}
-
 	@Override
 	public void close() throws IOException { if (online) socket.close(); }
 
 	private void writeObject(Object obj) throws IOException {
 		checkOnline();
-		logger.fine("Sending " + obj);
+		logger.log(Level.FINE, "Sending " + obj);
 		SerializationUtils.writeBytesWithLength(obj, socket.getOutputStream());
 	}
 
 	private void checkOnline() { if (!online) throw new IllegalStateException("Client is not online"); }
 
 	/**
-	 * @return the sender object that represents this client.
+	 * @return the {@link User} as which this client is logged in
 	 * @since Envoy Client v0.1-alpha
 	 */
 	public User getSender() { return sender; }
@@ -261,7 +255,7 @@ public class Client implements Closeable {
 	 * @param clientUser the client user to set
 	 * @since Envoy Client v0.2-alpha
 	 */
-	public void setSender(User clientUser) { this.sender = clientUser; }
+	public void setSender(User clientUser) { sender = clientUser; }
 
 	/**
 	 * @return the {@link Receiver} used by this {@link Client}
@@ -273,16 +267,4 @@ public class Client implements Closeable {
 	 * @since Envoy Client v0.2-alpha
 	 */
 	public boolean isOnline() { return online; }
-
-	/**
-	 * @return the contacts of this {@link Client}
-	 * @since Envoy Client v0.3-alpha
-	 */
-	public Set<? extends Contact> getContacts() { return contacts; }
-
-	/**
-	 * @param contacts the contacts to set
-	 * @since Envoy Client v0.3-alpha
-	 */
-	public void setContacts(Set<? extends Contact> contacts) { this.contacts = contacts; }
 }

src/main/java/envoy/client/net/MessageStatusChangeProcessor.java

@@ -5,30 +5,30 @@ import java.util.logging.Logger;
 
 import envoy.data.Message.MessageStatus;
 import envoy.event.EventBus;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.util.EnvoyLog;
 
 /**
  * Project: <strong>envoy-client</strong><br>
- * File: <strong>MessageStatusChangeEventProcessor.java</strong><br>
+ * File: <strong>MessageStatusChangeProcessor.java</strong><br>
  * Created: <strong>4 Feb 2020</strong><br>
  *
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class MessageStatusChangeEventProcessor implements Consumer<MessageStatusChangeEvent> {
+public class MessageStatusChangeProcessor implements Consumer<MessageStatusChange> {
 
-	private static final Logger logger = EnvoyLog.getLogger(MessageStatusChangeEventProcessor.class);
+	private static final Logger logger = EnvoyLog.getLogger(MessageStatusChangeProcessor.class);
 
 	/**
-	 * Dispatches a {@link MessageStatusChangeEvent} if the status is
+	 * Dispatches a {@link MessageStatusChange} if the status is
 	 * {@code RECEIVED} or {@code READ}.
 	 *
 	 * @param evt the status change event
 	 * @since Envoy Client v0.3-alpha
 	 */
 	@Override
-	public void accept(MessageStatusChangeEvent evt) {
+	public void accept(MessageStatusChange evt) {
 		if (evt.get().ordinal() < MessageStatus.RECEIVED.ordinal()) logger.warning("Received invalid message status change " + evt);
 		else EventBus.getInstance().dispatch(evt);
 	}

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

@@ -1,6 +1,7 @@
 package envoy.client.net;
 
 import java.util.function.Consumer;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import envoy.client.event.MessageCreationEvent;
@@ -23,7 +24,7 @@ public class ReceivedMessageProcessor implements Consumer<Message> {
 
 	@Override
 	public void accept(Message message) {
-		if (message.getStatus() != MessageStatus.SENT) logger.warning("The message has the unexpected status " + message.getStatus());
+		if (message.getStatus() != MessageStatus.SENT) logger.log(Level.WARNING, "The message has the unexpected status " + message.getStatus());
 		else {
 			// Update status to RECEIVED
 			message.nextStatus();

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

@@ -54,31 +54,31 @@ public class Receiver extends Thread {
 		try {
 			while (true) {
 				// Read object length
-				byte[] lenBytes = new byte[4];
+				final byte[] lenBytes = new byte[4];
 				in.read(lenBytes);
-				int len = SerializationUtils.bytesToInt(lenBytes, 0);
+				final int len = SerializationUtils.bytesToInt(lenBytes, 0);
 
 				// Read object into byte array
-				byte[] objBytes = new byte[len];
+				final byte[] objBytes = new byte[len];
 				in.read(objBytes);
 
 				try (ObjectInputStream oin = new ObjectInputStream(new ByteArrayInputStream(objBytes))) {
-					Object obj = oin.readObject();
+					final Object obj = oin.readObject();
-					logger.fine("Received " + obj);
+					logger.log(Level.FINE, "Received " + obj);
 
 					// Get appropriate processor
 					@SuppressWarnings("rawtypes")
-					Consumer processor = processors.get(obj.getClass());
+					final Consumer processor = processors.get(obj.getClass());
 					if (processor == null)
-						logger.warning(String.format("The received object has the class %s for which no processor is defined.", obj.getClass()));
+						logger.log(Level.WARNING, String.format(
+							"The received object has the class %s for which no processor is defined.", obj.getClass()));
 					else processor.accept(obj);
 				}
 			}
-		} catch (SocketException e) {
+		} catch (final SocketException e) {
 			// Connection probably closed by client.
-		} catch (Exception e) {
+		} catch (final Exception e) {
 			logger.log(Level.SEVERE, "Error on receiver thread", e);
-			e.printStackTrace();
 		}
 	}
 

src/main/java/envoy/client/net/WriteProxy.java

@@ -6,14 +6,14 @@ import java.util.logging.Logger;
 
 import envoy.client.data.LocalDB;
 import envoy.data.Message;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.util.EnvoyLog;
 
 /**
  * Implements methods to send {@link Message}s and
- * {@link MessageStatusChangeEvent}s to the server or cache them inside a
+ * {@link MessageStatusChange}s to the server or cache them inside a
- * {@link LocalDB} depending on the online status.<br>
+ * {@link LocalDB} depending on the online status.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>WriteProxy.java</strong><br>
  * Created: <strong>6 Feb 2020</strong><br>
@@ -45,27 +45,24 @@ public class WriteProxy {
 		// Initialize cache processors for messages and message status change events
 		localDB.getMessageCache().setProcessor(msg -> {
 			try {
-				logger.finer("Sending cached " + msg);
+				logger.log(Level.FINER, "Sending cached " + msg);
 				client.sendMessage(msg);
-
+			} catch (final IOException e) {
-				// Update message state to SENT in localDB
+				logger.log(Level.SEVERE, "Could not send cached message: ", e);
-				localDB.getMessage(msg.getID()).ifPresent(Message::nextStatus);
-			} catch (IOException e) {
-				logger.log(Level.SEVERE, "Could not send cached message", e);
 			}
 		});
 		localDB.getStatusCache().setProcessor(evt -> {
-			logger.finer("Sending cached " + evt);
+			logger.log(Level.FINER, "Sending cached " + evt);
 			try {
 				client.sendEvent(evt);
-			} catch (IOException e) {
+			} catch (final IOException e) {
-				logger.log(Level.SEVERE, "Could not send cached message status change event", e);
+				logger.log(Level.SEVERE, "Could not send cached message status change event: ", e);
 			}
 		});
 	}
 
 	/**
-	 * Sends cached {@link Message}s and {@link MessageStatusChangeEvent}s to the
+	 * Sends cached {@link Message}s and {@link MessageStatusChange}s to the
 	 * server.
 	 *
 	 * @since Envoy Client v0.3-alpha
@@ -99,7 +96,7 @@ public class WriteProxy {
 	 * @throws IOException if the event could not be sent
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public void writeMessageStatusChangeEvent(MessageStatusChangeEvent evt) throws IOException {
+	public void writeMessageStatusChange(MessageStatusChange evt) throws IOException {
 		if (client.isOnline()) client.sendEvent(evt);
 		else localDB.getStatusCache().accept(evt);
 	}

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

@@ -3,7 +3,6 @@ package envoy.client.ui;
 import javafx.scene.control.Label;
 import javafx.scene.control.ListCell;
 import javafx.scene.layout.VBox;
-import javafx.scene.paint.Color;
 
 import envoy.data.Contact;
 import envoy.data.Group;
@@ -32,32 +31,19 @@ public class ContactListCell extends ListCell<Contact> {
 			setText(null);
 			setGraphic(null);
 		} else {
-			// the infoLabel displays specific contact info, i.e. status of a user or amount
+			// Container with contact name
-			// of members in a group
+			final var vbox = new VBox(new Label(contact.getName()));
-			Label infoLabel = null;
 			if (contact instanceof User) {
-				// user specific info
+				// Online status
-				infoLabel = new Label(((User) contact).getStatus().toString());
+				final var	user		= (User) contact;
-				Color textColor = null;
+				final var	statusLabel	= new Label(user.getStatus().toString());
-				switch (((User) contact).getStatus()) {
+				statusLabel.getStyleClass().add(user.getStatus().toString().toLowerCase());
-					case ONLINE:
+				vbox.getChildren().add(statusLabel);
-						textColor = Color.LIMEGREEN;
+ 			} else {
-						break;
+				// Member count
-					case AWAY:
+				vbox.getChildren().add(new Label(((Group) contact).getContacts().size() + " members"));
-						textColor = Color.ORANGERED;
-						break;
-					case BUSY:
-						textColor = Color.RED;
-						break;
-					case OFFLINE:
-						textColor = Color.GRAY;
-						break;
 			}
-				infoLabel.setTextFill(textColor);
+			setGraphic(vbox);
-			} else
-				// group specific infos
-				infoLabel = new Label(String.valueOf(((Group) contact).getContacts().size()) + " members");
-			setGraphic(new VBox(new Label(contact.getName()), infoLabel));
 		}
 	}
 }

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

@@ -1,6 +1,5 @@
 package envoy.client.ui;
 
-import java.io.IOException;
 import java.util.EnumMap;
 import java.util.EnumSet;
 
@@ -8,11 +7,11 @@ import javafx.scene.image.Image;
 
 /**
  * Provides static utility methods for loading icons from the resource
- * folder.<br>
+ * folder.
- * <br>
+ * <p>
- * Project: <strong>envoy-client</strong>
+ * Project: <strong>envoy-client</strong><br>
- * File: <strong>IconUtil.java</strong>
+ * File: <strong>IconUtil.java</strong><br>
- * Created: <strong>16.03.2020</strong>
+ * Created: <strong>16.03.2020</strong><br>
  *
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
@@ -26,10 +25,9 @@ public class IconUtil {
 	 *
 	 * @param path the path to the icon inside the resource folder
 	 * @return the icon
-	 * @throws IOException if the loading process failed
 	 * @since Envoy Client v0.1-beta
 	 */
-	public static Image load(String path) throws IOException { return new Image(IconUtil.class.getResource(path).toExternalForm()); }
+	public static Image load(String path) { return new Image(IconUtil.class.getResource(path).toExternalForm()); }
 
 	/**
 	 * Loads an icon from the resource folder and scales it to a given size.
@@ -37,10 +35,9 @@ public class IconUtil {
 	 * @param path the path to the icon inside the resource folder
 	 * @param size the size to scale the icon to
 	 * @return the scaled icon
-	 * @throws IOException if the loading process failed
 	 * @since Envoy Client v0.1-beta
 	 */
-	public static Image load(String path, int size) throws IOException {
+	public static Image load(String path, int size) {
 		return new Image(IconUtil.class.getResource(path).toExternalForm(), size, size, true, true);
 	}
 
@@ -56,13 +53,12 @@ public class IconUtil {
 	 * @param size      the size to scale the icons to
 	 * @return a map containing the loaded icons with the corresponding enum
 	 *         constants as keys
-	 * @throws IOException if the loading process failed
 	 * @since Envoy Client v0.1-beta
 	 */
-	public static <T extends Enum<T>> EnumMap<T, Image> loadByEnum(Class<T> enumClass, int size) throws IOException {
+	public static <T extends Enum<T>> EnumMap<T, Image> loadByEnum(Class<T> enumClass, int size) {
-		var	icons	= new EnumMap<T, Image>(enumClass);
+		final var	icons	= new EnumMap<T, Image>(enumClass);
-		var	path	= "/icons/" + enumClass.getSimpleName().toLowerCase() + "/";
+		final var	path	= "/icons/" + enumClass.getSimpleName().toLowerCase() + "/";
-		for (var e : EnumSet.allOf(enumClass))
+		for (final var e : EnumSet.allOf(enumClass))
 			icons.put(e, load(path + e.toString().toLowerCase() + ".png", size));
 		return icons;
 	}

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

@@ -1,18 +1,18 @@
 package envoy.client.ui;
 
-import java.io.IOException;
+import java.time.format.DateTimeFormatter;
-import java.text.SimpleDateFormat;
 import java.util.Map;
 
+import javafx.geometry.Insets;
 import javafx.scene.control.Label;
 import javafx.scene.control.ListCell;
 import javafx.scene.image.Image;
 import javafx.scene.image.ImageView;
-import javafx.scene.layout.HBox;
 import javafx.scene.layout.VBox;
 
 import envoy.data.Message;
 import envoy.data.Message.MessageStatus;
+import envoy.data.User;
 
 /**
  * Displays a single message inside the message list.
@@ -26,16 +26,9 @@ import envoy.data.Message.MessageStatus;
  */
 public class MessageListCell extends ListCell<Message> {
 
-	private static final SimpleDateFormat		dateFormat	= new SimpleDateFormat("dd.MM.yyyy HH:mm");
+	private static User								client;
-	private static Map<MessageStatus, Image>	statusImages;
+	private static final DateTimeFormatter			dateFormat		= DateTimeFormatter.ofPattern("dd.MM.yyyy HH:mm");
-
+	private static final Map<MessageStatus, Image>	statusImages	= IconUtil.loadByEnum(MessageStatus.class, 16);
-	static {
-		try {
-			statusImages = IconUtil.loadByEnum(MessageStatus.class, 32);
-		} catch (IOException e) {
-			e.printStackTrace();
-		}
-	}
 
 	/**
 	 * Displays the text, the data of creation and the status of a message.
@@ -49,11 +42,19 @@ public class MessageListCell extends ListCell<Message> {
 			setText(null);
 			setGraphic(null);
 		} else {
-			setGraphic(new HBox(
+			final var cell = new VBox(new Label(dateFormat.format(message.getCreationDate())), new Label(message.getText()));
-					new VBox(
+			if (message.getRecipientID() == client.getID()) {
-					 new Label(dateFormat.format(message.getCreationDate())),
+				cell.getChildren().add(new Label("", new ImageView(statusImages.get(message.getStatus()))));
-					 new Label(message.getText())),
+				cell.getStyleClass().add("own-message");
-					new Label("", new ImageView(statusImages.get(message.getStatus())))));
+			} else cell.getStyleClass().add("received-message");
+			cell.paddingProperty().setValue(new Insets(5, 20, 5, 20));
+			setGraphic(cell);
 		}
 	}
+
+	/**
+	 * @param client the user who chats with another person
+	 * @since Envoy Client v0.1-beta
+	 */
+	public static void setUser(User client) { MessageListCell.client = client; }
 }

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

@@ -2,6 +2,7 @@ package envoy.client.ui;
 
 import java.io.IOException;
 import java.util.Stack;
+import java.util.logging.Level;
 
 import javafx.fxml.FXMLLoader;
 import javafx.scene.Parent;
@@ -11,6 +12,7 @@ import javafx.stage.Stage;
 import envoy.client.data.Settings;
 import envoy.client.event.ThemeChangeEvent;
 import envoy.event.EventBus;
+import envoy.util.EnvoyLog;
 
 /**
  * Manages a stack of scenes. The most recently added scene is displayed inside
@@ -35,7 +37,7 @@ public final class SceneContext {
 	 * @author Kai S. K. Engelbart
 	 * @since Envoy Client v0.1-beta
 	 */
-	public static enum SceneInfo {
+	public enum SceneInfo {
 
 		/**
 		 * The main scene in which chats are displayed.
@@ -117,7 +119,8 @@ public final class SceneContext {
 			applyCSS();
 			stage.sizeToScene();
 			stage.show();
-		} catch (IOException e) {
+		} catch (final IOException e) {
+			EnvoyLog.getLogger(SceneContext.class).log(Level.SEVERE, String.format("Could not load scene for %s: ", sceneInfo), e);
 			throw new RuntimeException(e);
 		}
 	}

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

@@ -16,7 +16,7 @@ import envoy.client.net.Client;
 import envoy.client.ui.SceneContext.SceneInfo;
 import envoy.client.ui.controller.LoginScene;
 import envoy.data.Message;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.exception.EnvoyException;
 import envoy.util.EnvoyLog;
 
@@ -33,10 +33,17 @@ import envoy.util.EnvoyLog;
  */
 public final class Startup extends Application {
 
+	/**
+	 * The version of this client. Used to verify compatibility with the server.
+	 *
+	 * @since Envoy Client v0.1-beta
+	 */
+	public static final String VERSION = "0.1-beta";
+
 	private LocalDB						localDB;
 	private Client						client;
 	private Cache<Message>				messageCache;
-	private Cache<MessageStatusChangeEvent>	messageStatusCache;
+	private Cache<MessageStatusChange>	messageStatusCache;
 
 	private static final ClientConfig	config	= ClientConfig.getInstance();
 	private static final Logger			logger	= EnvoyLog.getLogger(Startup.class);
@@ -63,6 +70,7 @@ public final class Startup extends Application {
 			if (!config.isInitialized()) throw new EnvoyException("Configuration is not fully initialized");
 		} catch (final Exception e) {
 			new Alert(AlertType.ERROR, "Error loading configuration values:\n" + e);
+			logger.log(Level.SEVERE, "Error loading configuration values: ", e);
 			e.printStackTrace();
 			System.exit(1);
 		}
@@ -73,20 +81,20 @@ public final class Startup extends Application {
 		EnvoyLog.setFileLevelBarrier(config.getFileLevelBarrier());
 		EnvoyLog.setConsoleLevelBarrier(config.getConsoleLevelBarrier());
 
+		logger.log(Level.INFO, "Envoy starting...");
+
 		// Initialize the local database
 		if (config.isIgnoreLocalDB()) {
 			localDB = new TransientLocalDB();
 			new Alert(AlertType.WARNING, "Ignoring local database.\nMessages will not be saved!").showAndWait();
-		} else {
+		} else try {
-			try {
 			localDB = new PersistentLocalDB(new File(config.getHomeDirectory(), config.getLocalDB().getPath()));
 		} catch (final IOException e3) {
-				logger.log(Level.SEVERE, "Could not initialize local database", e3);
+			logger.log(Level.SEVERE, "Could not initialize local database: ", e3);
 			new Alert(AlertType.ERROR, "Could not initialize local database!\n" + e3).showAndWait();
 			System.exit(1);
 			return;
 		}
-		}
 
 		// Initialize client and unread message cache
 		client				= new Client();
@@ -109,14 +117,15 @@ public final class Startup extends Application {
 	@Override
 	public void stop() {
 		try {
-			logger.info("Closing connection...");
+			logger.log(Level.INFO, "Closing connection...");
 			client.close();
 
-			logger.info("Saving local database and settings...");
+			logger.log(Level.INFO, "Saving local database and settings...");
 			localDB.save();
 			Settings.getInstance().save();
+			logger.log(Level.INFO, "Envoy was terminated by its user");
 		} catch (final Exception e) {
-			logger.log(Level.SEVERE, "Unable to save local files", e);
+			logger.log(Level.SEVERE, "Unable to save local files: ", e);
 		}
 	}
 

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

@@ -4,11 +4,13 @@ import java.awt.*;
 import java.awt.TrayIcon.MessageType;
 import java.awt.event.WindowAdapter;
 import java.awt.event.WindowEvent;
+import java.util.logging.Level;
 
 import envoy.client.event.MessageCreationEvent;
 import envoy.data.Message;
 import envoy.event.EventBus;
 import envoy.exception.EnvoyException;
+import envoy.util.EnvoyLog;
 
 /**
  * Project: <strong>envoy-client</strong><br>
@@ -25,7 +27,7 @@ public class StatusTrayIcon {
 	 * system tray. This includes displaying the icon, but also creating
 	 * notifications when new messages are received.
 	 */
-	private TrayIcon trayIcon;
+	private final TrayIcon trayIcon;
 
 	/**
 	 * A received {@link Message} is only displayed as a system tray notification if
@@ -46,16 +48,16 @@ public class StatusTrayIcon {
 	public StatusTrayIcon(Window focusTarget) throws EnvoyException {
 		if (!SystemTray.isSupported()) throw new EnvoyException("The Envoy tray icon is not supported.");
 
-		ClassLoader	loader	= Thread.currentThread().getContextClassLoader();
+		final ClassLoader	loader	= Thread.currentThread().getContextClassLoader();
-		Image		img		= Toolkit.getDefaultToolkit().createImage(loader.getResource("envoy_logo.png"));
+		final Image			img		= Toolkit.getDefaultToolkit().createImage(loader.getResource("envoy_logo.png"));
 		trayIcon = new TrayIcon(img, "Envoy Client");
 		trayIcon.setImageAutoSize(true);
 		trayIcon.setToolTip("You are notified if you have unread messages.");
 
-		PopupMenu popup = new PopupMenu();
+		final PopupMenu popup = new PopupMenu();
 
-		MenuItem exitMenuItem = new MenuItem("Exit");
+		final MenuItem exitMenuItem = new MenuItem("Exit");
-		exitMenuItem.addActionListener((evt) -> System.exit(0));
+		exitMenuItem.addActionListener(evt -> System.exit(0));
 		popup.add(exitMenuItem);
 
 		trayIcon.setPopupMenu(popup);
@@ -71,7 +73,7 @@ public class StatusTrayIcon {
 		});
 
 		// Show the window if the user clicks on the icon
-		trayIcon.addActionListener((evt) -> { focusTarget.setVisible(true); focusTarget.requestFocus(); });
+		trayIcon.addActionListener(evt -> { focusTarget.setVisible(true); focusTarget.requestFocus(); });
 
 		// Start processing message events
 		// TODO: Handle other message types
@@ -90,7 +92,8 @@ public class StatusTrayIcon {
 	public void show() throws EnvoyException {
 		try {
 			SystemTray.getSystemTray().add(trayIcon);
-		} catch (AWTException e) {
+		} catch (final AWTException e) {
+			EnvoyLog.getLogger(StatusTrayIcon.class).log(Level.INFO, "Could not display StatusTrayIcon: ", e);
 			throw new EnvoyException("Could not attach Envoy tray icon to system tray.", e);
 		}
 	}

src/main/java/envoy/client/ui/controller/ChatScene.java

@@ -1,5 +1,7 @@
 package envoy.client.ui.controller;
 
+import java.awt.Toolkit;
+import java.awt.datatransfer.StringSelection;
 import java.io.IOException;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -10,9 +12,11 @@ import javafx.collections.FXCollections;
 import javafx.fxml.FXML;
 import javafx.scene.control.*;
 import javafx.scene.control.Alert.AlertType;
+import javafx.scene.image.ImageView;
 import javafx.scene.input.KeyCode;
 import javafx.scene.input.KeyEvent;
 import javafx.scene.paint.Color;
+import javafx.scene.paint.Paint;
 
 import envoy.client.data.Chat;
 import envoy.client.data.LocalDB;
@@ -20,14 +24,12 @@ import envoy.client.data.Settings;
 import envoy.client.event.MessageCreationEvent;
 import envoy.client.net.Client;
 import envoy.client.net.WriteProxy;
-import envoy.client.ui.ContactListCell;
+import envoy.client.ui.*;
-import envoy.client.ui.MessageListCell;
-import envoy.client.ui.SceneContext;
 import envoy.data.*;
 import envoy.event.EventBus;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
-import envoy.event.UserStatusChangeEvent;
+import envoy.event.UserStatusChange;
-import envoy.event.contact.ContactOperationEvent;
+import envoy.event.contact.ContactOperation;
 import envoy.util.EnvoyLog;
 
 /**
@@ -61,11 +63,19 @@ public final class ChatScene {
 	@FXML
 	private Label remainingChars;
 
+	@FXML
+	private Label infoLabel;
+
+	@FXML
+	private MenuItem deleteContactMenuItem;
+
 	private LocalDB			localDB;
 	private Client			client;
 	private WriteProxy		writeProxy;
 	private SceneContext	sceneContext;
 
+	private boolean postingPermanentlyDisabled = false;
+
 	private Chat currentChat;
 
 	private static final Settings	settings			= Settings.getInstance();
@@ -85,6 +95,8 @@ public final class ChatScene {
 		messageList.setCellFactory(listView -> new MessageListCell());
 		userList.setCellFactory(listView -> new ContactListCell());
 
+		settingsButton.setGraphic(new ImageView(IconUtil.load("/icons/settings.png", 16)));
+
 		// Listen to received messages
 		eventBus.register(MessageCreationEvent.class, e -> {
 			final var message = e.get();
@@ -100,16 +112,20 @@ public final class ChatScene {
 				localDB.getChat(message.getRecipientID()).ifPresent(chat -> {
 					chat.getMessages().add(message);
 
-				// Update UI if in current chat
+				if (chat.equals(currentChat)) {
-				if (chat == currentChat)
+					try {
-					Platform.runLater(messageList::refresh);
+						currentChat.read(writeProxy);
+					} catch (final IOException e1) {
+						logger.log(Level.WARNING, "Could not read current chat: ", e1);
+					}
+					Platform.runLater(() -> { messageList.refresh(); scrollToMessageListEnd(); });
+				}
 				});
 			}
 		});
 
 		// Listen to message status changes
-		eventBus.register(MessageStatusChangeEvent.class, e ->
+		eventBus.register(MessageStatusChange.class, e -> localDB.getMessage(e.getID()).ifPresent(message -> {
-			localDB.getMessage(e.getID()).ifPresent(message -> {
 			message.setStatus(e.get());
 
 			// Update UI if in current chat
@@ -117,19 +133,15 @@ public final class ChatScene {
 		}));
 
 		// Listen to user status changes
-		eventBus.register(UserStatusChangeEvent.class, e ->
+		eventBus.register(UserStatusChange.class,
-			userList.getItems()
+				e -> userList.getItems()
 					.stream()
 					.filter(c -> c.getID() == e.getID())
 					.findAny()
-				.ifPresent(u -> {
+					.ifPresent(u -> { ((User) u).setStatus(e.get()); Platform.runLater(userList::refresh); }));
-					((User) u).setStatus(e.get());
-					Platform.runLater(userList::refresh);
-				})
-		);
 
 		// Listen to contacts changes
-		eventBus.register(ContactOperationEvent.class, e -> {
+		eventBus.register(ContactOperation.class, e -> {
 			final var contact = e.get();
 			switch (e.getOperationType()) {
 				case ADD:
@@ -163,6 +175,9 @@ public final class ChatScene {
 		this.writeProxy		= writeProxy;
 
 		userList.setItems(FXCollections.observableList(localDB.getChats().stream().map(Chat::getRecipient).collect(Collectors.toList())));
+		contactLabel.setText(localDB.getUser().getName());
+		MessageListCell.setUser(localDB.getUser());
+		if (!client.isOnline()) updateInfoLabel("You are offline", Color.YELLOW);
 	}
 
 	/**
@@ -173,23 +188,29 @@ public final class ChatScene {
 	@FXML
 	private void userListClicked() {
 		final Contact user = userList.getSelectionModel().getSelectedItem();
-		if (user != null && (currentChat == null || user.getID() != currentChat.getRecipient().getID())) {
+		if (user != null && (currentChat == null || !user.equals(currentChat.getRecipient()))) {
-			contactLabel.setText(user.getName());
+			logger.log(Level.FINEST, "Loading chat with " + user);
 
 			// LEON: JFC <===> JAVA FRIED CHICKEN <=/=> Java Foundation Classes
 
-			// Load the chat or create a new one and add it to the LocalDB
+			// Load the chat
-			currentChat = localDB
+			currentChat = localDB.getChat(user.getID()).get();
-				.getChat(user.getID())
-				.orElseGet(() -> { final var chat = new Chat(user); localDB.getChats().add(chat); return chat; });
 
 			messageList.setItems(FXCollections.observableList(currentChat.getMessages()));
+			deleteContactMenuItem.setText("Delete " + user.getName());
+
+			// Read the current chat
+			try {
+				currentChat.read(writeProxy);
+			} catch (final IOException e) {
+				logger.log(Level.WARNING, "Could not read current chat.", e);
+			}
 
 			remainingChars.setVisible(true);
 			remainingChars
 				.setText(String.format("remaining chars: %d/%d", MAX_MESSAGE_LENGTH - messageTextArea.getText().length(), MAX_MESSAGE_LENGTH));
 		}
-		messageTextArea.setDisable(currentChat == null);
+		messageTextArea.setDisable(currentChat == null || postingPermanentlyDisabled);
 	}
 
 	/**
@@ -214,6 +235,42 @@ public final class ChatScene {
 		sceneContext.<ContactSearchScene>getController().initializeData(sceneContext, localDB);
 	}
 
+	/**
+	 * Checks the text length of the {@code messageTextArea}, adjusts the
+	 * {@code remainingChars} label and checks whether to send the message
+	 * automatically.
+	 *
+	 * @param e the key event that will be analyzed for a post request
+	 * @since Envoy Client v0.1-beta
+	 */
+	@FXML
+	private void checkKeyCombination(KeyEvent e) {
+		// Checks whether the text is too long
+		messageTextUpdated();
+		// Automatic sending of messages via (ctrl +) enter
+		checkPostConditions(e);
+	}
+
+	/**
+	 * @param e the keys that have been pressed
+	 * @since Envoy Client v0.1-beta
+	 */
+	@FXML
+	private void checkPostConditions(KeyEvent e) {
+		if (!postingPermanentlyDisabled) {
+			if (!postButton.isDisabled() && (settings.isEnterToSend() && e.getCode() == KeyCode.ENTER
+					|| !settings.isEnterToSend() && e.getCode() == KeyCode.ENTER && e.isControlDown()))
+				postMessage();
+			postButton.setDisable(messageTextArea.getText().isBlank() || currentChat == null);
+		} else {
+			final var noMoreMessaging = "Go online to send messages";
+			if (!infoLabel.getText().equals(noMoreMessaging))
+				// Informing the user that he is a f*cking moron and should use Envoy online
+				// because he ran out of messageIDs to use
+				updateInfoLabel(noMoreMessaging, Color.RED);
+		}
+	}
+
 	/**
 	 * Actions to perform when the text was updated in the messageTextArea.
 	 *
@@ -227,29 +284,21 @@ public final class ChatScene {
 			messageTextArea.positionCaret(MAX_MESSAGE_LENGTH);
 			messageTextArea.setScrollTop(Double.MAX_VALUE);
 		}
+		updateRemainingCharsLabel();
+	}
 
-		// Redesigning the remainingChars - Label
+	/**
+	 * Sets the text and text color of the {@code remainingChars} label.
+	 *
+	 * @since Envoy Client v0.1-beta
+	 */
+	private void updateRemainingCharsLabel() {
 		final int	currentLength	= messageTextArea.getText().length();
 		final int	remainingLength	= MAX_MESSAGE_LENGTH - currentLength;
 		remainingChars.setText(String.format("remaining chars: %d/%d", remainingLength, MAX_MESSAGE_LENGTH));
 		remainingChars.setTextFill(Color.rgb(currentLength, remainingLength, 0, 1));
 	}
 
-	/**
-	 * Actions to perform when a key has been entered.
-	 *
-	 * @param e the Keys that have been entered
-	 * @since Envoy Client v0.1-beta
-	 */
-	@FXML
-	private void checkKeyCombination(KeyEvent e) {
-		// Automatic sending of messages via (ctrl +) enter
-		if (!postButton.isDisabled() && settings.isEnterToSend() && e.getCode() == KeyCode.ENTER
-				|| !settings.isEnterToSend() && e.getCode() == KeyCode.ENTER && e.isControlDown())
-			postMessage();
-		postButton.setDisable(messageTextArea.getText().isBlank() || currentChat == null);
-	}
-
 	/**
 	 * Sends a new message or groupMessage to the server based on the text entered
 	 * in the
@@ -259,6 +308,16 @@ public final class ChatScene {
 	 */
 	@FXML
 	private void postMessage() {
+		postingPermanentlyDisabled = !(client.isOnline() || localDB.getIDGenerator().hasNext());
+		if (postingPermanentlyDisabled) {
+			postButton.setDisable(true);
+			messageTextArea.setDisable(true);
+			messageTextArea.clear();
+			updateInfoLabel("You need to go online to send more messages", Color.RED);
+			return;
+		}
+		final var text = messageTextArea.getText().strip();
+		if (text.isBlank()) throw new IllegalArgumentException("A message without visible text can not be sent.");
 		try {
 			if (currentChat.getRecipient().getClass().equals(Group.class)) {
 				// Create and send groupMessage
@@ -283,17 +342,72 @@ public final class ChatScene {
 				// Add message to LocalDB and update UI
 				messageList.getItems().add(message);
 			}
+			scrollToMessageListEnd();
 
 			// Request a new ID generator if all IDs were used
 			if (!localDB.getIDGenerator().hasNext() && client.isOnline()) client.requestIdGenerator();
 
 		} catch (final IOException e) {
-			logger.log(Level.SEVERE, "Error sending message", e);
+			logger.log(Level.SEVERE, "Error while sending message: ", e);
 			new Alert(AlertType.ERROR, "An error occured while sending the message!").showAndWait();
 		}
 
 		// Clear text field and disable post button
 		messageTextArea.setText("");
 		postButton.setDisable(true);
+		updateRemainingCharsLabel();
+	}
+
+	/**
+	 * Scrolls to the bottom of the {@code messageList}.
+	 *
+	 * @since Envoy Client v0.1-beta
+	 */
+	private void scrollToMessageListEnd() { messageList.scrollTo(messageList.getItems().size() - 1); }
+
+	/**
+	 * Updates the {@code infoLabel}.
+	 *
+	 * @param text     the text to use
+	 * @param textfill the color in which to display information
+	 * @since Envoy Client v0.1-beta
+	 */
+	private void updateInfoLabel(String text, Paint textfill) {
+		infoLabel.setText(text);
+		infoLabel.setTextFill(textfill);
+		infoLabel.setVisible(true);
+	}
+
+	// Context menu actions
+
+	@FXML
+	private void copyMessage() {
+		try {
+			Toolkit.getDefaultToolkit()
+				.getSystemClipboard()
+				.setContents(new StringSelection(messageList.getSelectionModel().getSelectedItem().getText()), null);
+		} catch (final NullPointerException e) {}
+	}
+
+	@FXML
+	private void deleteMessage() { try {} catch (final NullPointerException e) {} }
+
+	@FXML
+	private void forwardMessage() { try {} catch (final NullPointerException e) {} }
+
+	@FXML
+	private void quoteMessage() { try {} catch (final NullPointerException e) {} }
+
+	@FXML
+	private void deleteContact() { try {} catch (final NullPointerException e) {} }
+
+	@FXML
+	private void copyAndPostMessage() {
+		final var messageText = messageTextArea.getText();
+		Toolkit.getDefaultToolkit().getSystemClipboard().setContents(new StringSelection(messageText), null);
+		postMessage();
+		messageTextArea.setText(messageText);
+		updateRemainingCharsLabel();
+		postButton.setDisable(messageText.isBlank());
 	}
 }

src/main/java/envoy/client/ui/controller/ContactSearchScene.java

@@ -15,7 +15,7 @@ import envoy.client.ui.SceneContext;
 import envoy.data.Contact;
 import envoy.event.ElementOperation;
 import envoy.event.EventBus;
-import envoy.event.contact.ContactOperationEvent;
+import envoy.event.contact.ContactOperation;
 import envoy.event.contact.ContactSearchRequest;
 import envoy.event.contact.ContactSearchResult;
 import envoy.util.EnvoyLog;
@@ -57,6 +57,7 @@ public class ContactSearchScene {
 
 	/**
 	 * @param sceneContext enables the user to return to the chat scene
+	 * @param localDB      the local database to which new contacts are added
 	 * @since Envoy Client v0.1-beta
 	 */
 	public void initializeData(SceneContext sceneContext, LocalDB localDB) {
@@ -67,10 +68,8 @@ public class ContactSearchScene {
 	@FXML
 	private void initialize() {
 		contactList.setCellFactory(e -> new ContactListCell());
-		eventBus.register(ContactSearchResult.class, response -> Platform.runLater(() -> {
+		eventBus.register(ContactSearchResult.class,
-			contactList.getItems().clear();
+				response -> Platform.runLater(() -> { contactList.getItems().clear(); contactList.getItems().addAll(response.get()); }));
-			contactList.getItems().addAll(response.get());
-		}));
 	}
 
 	/**
@@ -108,7 +107,7 @@ public class ContactSearchScene {
 	}
 
 	/**
-	 * Sends an {@link ContactOperationEvent} for every selected contact to the
+	 * Sends an {@link ContactOperation} for every selected contact to the
 	 * server.
 	 *
 	 * @since Envoy Client v0.1-beta
@@ -121,7 +120,7 @@ public class ContactSearchScene {
 			alert.setTitle("Add Contact to Contact List");
 			alert.setHeaderText("Add the user " + contact.getName() + " to your contact list?");
 			alert.showAndWait().filter(btn -> btn == ButtonType.OK).ifPresent(btn -> {
-				final var event = new ContactOperationEvent(contact, ElementOperation.ADD);
+				final var event = new ContactOperation(contact, ElementOperation.ADD);
 				// Sends the event to the server
 				eventBus.dispatch(new SendEvent(event));
 				// Updates the UI

src/main/java/envoy/client/ui/controller/GroupCreationScene.java

@@ -5,15 +5,16 @@ import java.util.stream.Collectors;
 import javafx.application.Platform;
 import javafx.fxml.FXML;
 import javafx.scene.control.*;
+import javafx.scene.control.Alert.AlertType;
 
 import envoy.client.data.LocalDB;
 import envoy.client.event.SendEvent;
 import envoy.client.ui.ContactListCell;
 import envoy.client.ui.SceneContext;
 import envoy.data.Contact;
-import envoy.data.User;
 import envoy.event.EventBus;
-import envoy.event.GroupCreationEvent;
+import envoy.event.GroupCreation;
+import envoy.util.Bounds;
 
 /**
  * Project: <strong>envoy-client</strong><br>
@@ -25,21 +26,18 @@ import envoy.event.GroupCreationEvent;
  */
 public class GroupCreationScene {
 
-	@FXML
-	private Button backButton;
-
 	@FXML
 	private Button createButton;
 
 	@FXML
-	private TextField groupNameBar;
+	private TextField groupNameField;
 
 	@FXML
 	private ListView<Contact> contactList;
 
 	private SceneContext sceneContext;
 
-	private static EventBus		eventBus	= EventBus.getInstance();
+	private static final EventBus eventBus = EventBus.getInstance();
 
 	@FXML
 	private void initialize() {
@@ -49,27 +47,43 @@ public class GroupCreationScene {
 
 	/**
 	 * @param sceneContext enables the user to return to the chat scene
+	 * @param localDB      the local database from which potential group members can
+	 *                     be selected
 	 * @since Envoy Client v0.1-beta
 	 */
 	public void initializeData(SceneContext sceneContext, LocalDB localDB) {
 		this.sceneContext = sceneContext;
 		Platform.runLater(() -> contactList.getItems()
-			.addAll(localDB.getUsers()
+			.addAll(localDB.getUsers().values().stream().filter(c -> c.getID() != localDB.getUser().getID()).collect(Collectors.toList())));
-				.values()
-				.stream()
-				.filter(c -> c instanceof User && c.getID() != localDB.getUser().getID())
-				.collect(Collectors.toList())));
 	}
 
 	/**
-	 * Sends a {@link GroupCreationEvent} to the server.
+	 * Enables the {@code createButton} if at least one contact is selected.
 	 * 
 	 * @since Envoy Client v0.1-beta
 	 */
 	@FXML
-	private void sendGroupObject() {
+	private void contactListClicked() { createButton.setDisable(contactList.getSelectionModel().isEmpty()); }
-		eventBus.dispatch(new SendEvent(new GroupCreationEvent(groupNameBar.getText(),
+
+	/**
+	 * Sends a {@link GroupCreation} to the server and closes this scene.
+	 * <p>
+	 * If the given group name is not valid, an error is displayed instead.
+	 *
+	 * @since Envoy Client v0.1-beta
+	 */
+	@FXML
+	private void createButtonClicked() {
+		final var name = groupNameField.getText();
+		if (!Bounds.isValidContactName(name)) {
+			new Alert(AlertType.ERROR, "The entered group name is not valid (" + Bounds.CONTACT_NAME_PATTERN + ")").showAndWait();
+			groupNameField.clear();
+		} else {
+			eventBus.dispatch(new SendEvent(new GroupCreation(name,
 					contactList.getSelectionModel().getSelectedItems().stream().map(Contact::getID).collect(Collectors.toSet()))));
+			new Alert(AlertType.INFORMATION, String.format("Group '%s' successfully created.", name)).showAndWait();
+			sceneContext.pop();
+		}
 	}
 
 	@FXML

src/main/java/envoy/client/ui/controller/LoginScene.java

@@ -3,6 +3,7 @@ package envoy.client.ui.controller;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.concurrent.TimeoutException;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import javafx.application.Platform;
@@ -10,19 +11,19 @@ import javafx.fxml.FXML;
 import javafx.scene.control.*;
 import javafx.scene.control.Alert.AlertType;
 
-import envoy.client.data.Cache;
+import envoy.client.data.*;
-import envoy.client.data.ClientConfig;
-import envoy.client.data.LocalDB;
 import envoy.client.net.Client;
 import envoy.client.ui.SceneContext;
+import envoy.client.ui.Startup;
 import envoy.data.LoginCredentials;
 import envoy.data.Message;
 import envoy.data.User;
 import envoy.data.User.UserStatus;
 import envoy.event.EventBus;
-import envoy.event.HandshakeRejectionEvent;
+import envoy.event.HandshakeRejection;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.exception.EnvoyException;
+import envoy.util.Bounds;
 import envoy.util.EnvoyLog;
 
 /**
@@ -57,7 +58,7 @@ public final class LoginScene {
 	private Client						client;
 	private LocalDB						localDB;
 	private Cache<Message>				receivedMessageCache;
-	private Cache<MessageStatusChangeEvent>	receivedMessageStatusChangeEventCache;
+	private Cache<MessageStatusChange>	receivedMessageStatusChangeCache;
 	private SceneContext				sceneContext;
 
 	private static final Logger			logger		= EnvoyLog.getLogger(LoginScene.class);
@@ -69,28 +70,33 @@ public final class LoginScene {
 		connectionLabel.setText("Server: " + config.getServer() + ":" + config.getPort());
 
 		// Show an alert after an unsuccessful handshake
-		eventBus.register(HandshakeRejectionEvent.class,
+		eventBus.register(HandshakeRejection.class, e -> Platform.runLater(() -> { new Alert(AlertType.ERROR, e.get()).showAndWait(); }));
-				e -> Platform.runLater(() -> { clearPasswordFields(); new Alert(AlertType.ERROR, e.get()).showAndWait(); }));
 	}
 
 	/**
 	 * Loads the login dialog using the FXML file {@code LoginDialog.fxml}.
 	 *
-	 * @param client               the client used to perform the handshake
+	 * @param client                           the client used to perform the
-	 * @param localDB              the local database used for offline login
+	 *                                         handshake
-	 * @param receivedMessageCache the cache storing messages received during
+	 * @param localDB                          the local database used for offline
+	 *                                         login
+	 * @param receivedMessageCache             the cache storing messages received
+	 *                                         during
 	 *                                         the handshake
-	 * @param receivedMessageStatusChangeEventCache the cache storing messageStatusChangeEvents received during handshake
+	 * @param receivedMessageStatusChangeCache the cache storing
-	 * @param sceneContext         the scene context used to initialize the chat
+	 *                                         messageStatusChangeEvents received
+	 *                                         during handshake
+	 * @param sceneContext                     the scene context used to initialize
+	 *                                         the chat
 	 *                                         scene
 	 * @since Envoy Client v0.1-beta
 	 */
 	public void initializeData(Client client, LocalDB localDB, Cache<Message> receivedMessageCache,
-			Cache<MessageStatusChangeEvent> receivedMessageStatusChangeEventCache, SceneContext sceneContext) {
+			Cache<MessageStatusChange> receivedMessageStatusChangeCache, SceneContext sceneContext) {
 		this.client								= client;
 		this.localDB							= localDB;
 		this.receivedMessageCache				= receivedMessageCache;
-		this.receivedMessageStatusChangeEventCache	= receivedMessageStatusChangeEventCache;
+		this.receivedMessageStatusChangeCache	= receivedMessageStatusChangeCache;
 		this.sceneContext						= sceneContext;
 
 		// Prepare handshake
@@ -108,14 +114,19 @@ public final class LoginScene {
 
 		// Prevent registration with unequal passwords
 		if (registerCheckBox.isSelected() && !passwordField.getText().equals(repeatPasswordField.getText())) {
-			clearPasswordFields();
 			new Alert(AlertType.ERROR, "The entered password is unequal to the repeated one").showAndWait();
-		} else performHandshake(new LoginCredentials(userTextField.getText(), passwordField.getText().toCharArray(), registerCheckBox.isSelected()));
+			repeatPasswordField.clear();
+		} else if (!Bounds.isValidContactName(userTextField.getText())) {
+			new Alert(AlertType.ERROR, "The entered user name is not valid (" + Bounds.CONTACT_NAME_PATTERN + ")").showAndWait();
+			userTextField.clear();
+		} else
+			performHandshake(
+				new LoginCredentials(userTextField.getText(), passwordField.getText().toCharArray(), registerCheckBox.isSelected(), Startup.VERSION));
 	}
 
 	@FXML
 	private void offlineModeButtonPressed() {
-		attemptOfflineMode(new LoginCredentials(userTextField.getText(), passwordField.getText().toCharArray(), false));
+		attemptOfflineMode(new LoginCredentials(userTextField.getText(), passwordField.getText().toCharArray(), false, Startup.VERSION));
 	}
 
 	@FXML
@@ -124,25 +135,24 @@ public final class LoginScene {
 		// Make repeat password field and label visible / invisible
 		repeatPasswordField.setVisible(registerCheckBox.isSelected());
 		repeatPasswordLabel.setVisible(registerCheckBox.isSelected());
-		clearPasswordFields();
 	}
 
 	@FXML
 	private void abortLogin() {
-		logger.info("The login process has been cancelled. Exiting...");
+		logger.log(Level.INFO, "The login process has been cancelled. Exiting...");
 		System.exit(0);
 	}
 
 	private void performHandshake(LoginCredentials credentials) {
 		try {
-			client.performHandshake(credentials, receivedMessageCache, receivedMessageStatusChangeEventCache);
+			client.performHandshake(credentials, receivedMessageCache, receivedMessageStatusChangeCache);
 			if (client.isOnline()) {
-				client.initReceiver(localDB, receivedMessageCache, receivedMessageStatusChangeEventCache);
+				client.initReceiver(localDB, receivedMessageCache, receivedMessageStatusChangeCache);
 				loadChatScene();
 			}
 		} catch (IOException | InterruptedException | TimeoutException e) {
-			logger.warning("Could not connect to server: " + e);
+			logger.log(Level.WARNING, "Could not connect to server: ", e);
-			logger.finer("Attempting offline mode...");
+			logger.log(Level.FINER, "Attempting offline mode...");
 			attemptOfflineMode(credentials);
 		}
 	}
@@ -154,10 +164,10 @@ public final class LoginScene {
 			final User clientUser = (User) localDB.getUsers().get(credentials.getIdentifier());
 			if (clientUser == null) throw new EnvoyException("Could not enter offline mode: user name unknown");
 			client.setSender(clientUser);
-			new Alert(AlertType.WARNING, "A connection to the server could not be established. Starting in offline mode.").showAndWait();
 			loadChatScene();
 		} catch (final Exception e) {
 			new Alert(AlertType.ERROR, "Client error: " + e).showAndWait();
+			logger.log(Level.SEVERE, "Offline mode could not be loaded: ", e);
 			System.exit(1);
 		}
 	}
@@ -174,22 +184,24 @@ public final class LoginScene {
 		} catch (final FileNotFoundException e) {
 			// The local database file has not yet been created, probably first login
 		} catch (final Exception e) {
-			e.printStackTrace();
 			new Alert(AlertType.ERROR, "Error while loading local database: " + e + "\nChats will not be stored locally.").showAndWait();
+			logger.log(Level.WARNING, "Could not load local database: ", e);
 		}
 
 		// Initialize write proxy
 		final var writeProxy = client.createWriteProxy(localDB);
 
-		if (client.isOnline()) {
+		localDB.synchronize();
 
-			// Save all users to the local database and flush cache
+		if (client.isOnline()) writeProxy.flushCache();
-			localDB.setUsers(client.getUsers());
+		else
-			localDB.createMissingChats();
-			writeProxy.flushCache();
-		} else
 			// Set all contacts to offline mode
-			localDB.getUsers().values().stream().filter(User.class::isInstance).map(User.class::cast).forEach(u -> u.setStatus(UserStatus.OFFLINE));
+			localDB.getChats()
+				.stream()
+				.map(Chat::getRecipient)
+				.filter(User.class::isInstance)
+				.map(User.class::cast)
+				.forEach(u -> u.setStatus(UserStatus.OFFLINE));
 
 		// Load ChatScene
 		sceneContext.pop();
@@ -200,11 +212,6 @@ public final class LoginScene {
 
 		// Relay unread messages from cache
 		if (receivedMessageCache != null && client.isOnline()) receivedMessageCache.relay();
-		if (receivedMessageStatusChangeEventCache != null && client.isOnline()) receivedMessageStatusChangeEventCache.relay();
+		if (receivedMessageStatusChangeCache != null && client.isOnline()) receivedMessageStatusChangeCache.relay();
-	}
-
-	private void clearPasswordFields() {
-		passwordField.clear();
-		repeatPasswordField.clear();
 	}
 }

src/main/java/envoy/client/ui/settings/package-info.java

@@ -1,7 +1,7 @@
 /**
  * This package contains classes used for representing the settings
- * visually.<br>
+ * visually.
- * <br>
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>package-info.java</strong><br>
  * Created: <strong>19 Apr 2020</strong><br>

src/main/resources/css/base.css

@@ -1,3 +1,60 @@
-.button {
+.button, .list-cell {
-	-fx-background-radius: 5em;
+	-fx-background-radius: 5.0em;
+}
+
+.context-menu, .context-menu > * {
+	-fx-background-radius: 15px;
+	/*TODO: solution below does not work */
+	-fx-background-color: transparent;
+}
+
+.menu-item {
+	-fx-background-radius: 15.0px;
+}
+
+.button:hover {
+	-fx-scale-x: 1.05;
+	-fx-scale-y: 1.05;
+}
+
+.label {
+	-fx-background-color: transparent;
+}
+
+.scroll-bar:horizontal, .scroll-bar:horizontal *, .scroll-bar:horizontal > *{
+	-fx-background-color: transparent;
+	-fx-text-fill: transparent;
+}
+
+.online {
+	-fx-text-fill: limegreen;
+}
+
+.away {
+	-fx-text-fill: orangered;
+}
+
+.busy {
+	-fx-text-fill: red;
+}
+
+.offline {
+	-fx-text-fill: gray;
+}
+
+.received-message {
+	-fx-alignment: center-left;
+	-fx-background-radius: 4.0em;
+	-fx-text-alignment: right;
+}
+
+.own-message {
+	-fx-alignment: center-right;
+	-fx-background-radius: 4.0em;
+	-fx-text-alignment: left;
+}
+
+#remainingCharsLabel {
+	-fx-text-fill: #00FF00;
+	-fx-background-color: transparent;
 }

src/main/resources/css/dark.css

@@ -1,4 +1,39 @@
-.button{
+* {
-	-fx-background-color: rgb(105,0,153);
 	-fx-text-fill: white;
 }
+
+.root {
+	-fx-background-color: black;
+}
+
+.button {
+	-fx-background-color: rgb(105.0,0.0,153.0);
+}
+
+.button:pressed {
+	-fx-background-color: darkgray;
+}
+
+.button:disabled {
+	-fx-background-color: lightgray;
+}
+
+.list-view, .list-cell, .text-area .content, .text-field, .password-field, .tooltip, .pane, .pane .content, .vbox, .titled-pane > .title, .titled-pane > *.content, .context-menu, .menu-item {
+	-fx-background-color: dimgray;
+}
+
+.list-cell:selected, .list-cell:selected > *, .menu-item:hover {
+    -fx-background-color: rgb(105.0,0.0,153.0);
+}
+
+.received-message {
+	-fx-background-color: gray;
+}
+
+.own-message {
+	-fx-background-color: #8fa88f;
+}
+
+.alert.information.dialog-pane, .alert.warning.dialog-pane, .alert.error.dialog-pane {
+	-fx-background-color: black;
+}

src/main/resources/css/light.css

@@ -1,3 +1,16 @@
 .button{
-	-fx-background-color: snow;
+	-fx-background-color: orangered;
+}
+
+.list-cell:selected, .list-cell:selected > * {
+	-fx-background-color: orangered;
+	-fx-text-fill: black;
+}
+
+.received-message, .menu-item {
+	-fx-background-color: lightgray;
+}
+
+.own-message {
+	-fx-background-color: lightgreen;
 }

src/main/resources/fxml/ChatScene.fxml

@@ -2,41 +2,181 @@
 
 <?import javafx.geometry.Insets?>
 <?import javafx.scene.control.Button?>
+<?import javafx.scene.control.ContextMenu?>
 <?import javafx.scene.control.Label?>
 <?import javafx.scene.control.ListView?>
+<?import javafx.scene.control.MenuItem?>
 <?import javafx.scene.control.TextArea?>
+<?import javafx.scene.control.Tooltip?>
 <?import javafx.scene.layout.ColumnConstraints?>
 <?import javafx.scene.layout.GridPane?>
 <?import javafx.scene.layout.RowConstraints?>
 
-<GridPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="400.0" minWidth="350.0" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="envoy.client.ui.controller.ChatScene">
+<GridPane maxHeight="-Infinity" maxWidth="-Infinity"
+	minHeight="400.0" minWidth="350.0" prefHeight="400.0" prefWidth="600.0"
+	xmlns="http://javafx.com/javafx/11.0.1"
+	xmlns:fx="http://javafx.com/fxml/1"
+	fx:controller="envoy.client.ui.controller.ChatScene">
 	<columnConstraints>
-		<ColumnConstraints hgrow="SOMETIMES" maxWidth="1.7976931348623157E308" minWidth="10.0" percentWidth="20.0" prefWidth="161.0" />
+		<ColumnConstraints hgrow="SOMETIMES"
-		<ColumnConstraints hgrow="SOMETIMES" maxWidth="1.7976931348623157E308" minWidth="10.0" percentWidth="65.0" prefWidth="357.0" />
+			maxWidth="1.7976931348623157E308" minWidth="10.0" percentWidth="25.0"
-      <ColumnConstraints hgrow="SOMETIMES" maxWidth="1.7976931348623157E308" minWidth="6.285736083984375" percentWidth="15.0" prefWidth="48.000030517578125" />
+			prefWidth="161.0" />
+		<ColumnConstraints hgrow="SOMETIMES"
+			maxWidth="1.7976931348623157E308" minWidth="10.0" percentWidth="65.0"
+			prefWidth="357.0" />
+		<ColumnConstraints hgrow="SOMETIMES" maxWidth="10.0"
+			minWidth="10.0" percentWidth="10.0" prefWidth="10.0" />
 	</columnConstraints>
 	<rowConstraints>
-		<RowConstraints maxHeight="1.7976931348623157E308" minHeight="10.0" percentHeight="10.0" prefHeight="70.0" vgrow="SOMETIMES" />
+		<RowConstraints maxHeight="1.7976931348623157E308"
-		<RowConstraints maxHeight="1.7976931348623157E308" minHeight="10.0" percentHeight="70.0" prefHeight="326.2857404436384" vgrow="SOMETIMES" />
+			minHeight="10.0" percentHeight="10.0" prefHeight="70.0"
-      <RowConstraints maxHeight="1.7976931348623157E308" minHeight="10.0" percentHeight="5.0" prefHeight="50.0" vgrow="SOMETIMES" />
+			vgrow="SOMETIMES" />
-		<RowConstraints maxHeight="1.7976931348623157E308" minHeight="10.0" percentHeight="15.0" prefHeight="100.0" vgrow="SOMETIMES" />
+		<RowConstraints maxHeight="1.7976931348623157E308"
+			minHeight="10.0" percentHeight="7.0" vgrow="SOMETIMES" />
+		<RowConstraints maxHeight="1.7976931348623157E308"
+			minHeight="10.0" percentHeight="60.0" prefHeight="50.0"
+			vgrow="SOMETIMES" />
+		<RowConstraints maxHeight="50.0" minHeight="10.0"
+			percentHeight="2.0" prefHeight="50.0" vgrow="SOMETIMES" />
+		<RowConstraints maxHeight="1.7976931348623157E308"
+			minHeight="10.0" percentHeight="21.0" prefHeight="100.0"
+			vgrow="SOMETIMES" />
 	</rowConstraints>
 	<children>
-		<ListView fx:id="userList" onMouseClicked="#userListClicked" prefHeight="211.0" prefWidth="300.0" GridPane.rowIndex="1" GridPane.rowSpan="2147483647" />
+		<ListView fx:id="userList" onMouseClicked="#userListClicked"
-		<Label fx:id="contactLabel" prefHeight="16.0" prefWidth="250.0" text="Select a contact to chat with" GridPane.columnSpan="2" />
+			prefHeight="211.0" prefWidth="300.0" GridPane.rowIndex="1"
-		<Button fx:id="settingsButton" mnemonicParsing="true" onAction="#settingsButtonClicked" text="_Settings" GridPane.columnIndex="2" GridPane.halignment="CENTER" GridPane.valignment="CENTER" />
+			GridPane.rowSpan="2147483647">
-		<ListView fx:id="messageList" prefHeight="257.0" prefWidth="155.0" GridPane.columnIndex="1" GridPane.columnSpan="2" GridPane.rowIndex="1" GridPane.rowSpan="2" />
+			<GridPane.margin>
-		<Button fx:id="postButton" defaultButton="true" disable="true" mnemonicParsing="true" onAction="#postMessage" prefHeight="10.0" prefWidth="65.0" text="_Post" GridPane.columnIndex="2" GridPane.halignment="CENTER" GridPane.rowIndex="3" GridPane.valignment="CENTER" />
+				<Insets bottom="10.0" left="10.0" right="5.0" top="5.0" />
-      	<TextArea fx:id="messageTextArea" disable="true" onInputMethodTextChanged="#messageTextUpdated" onKeyPressed="#checkKeyCombination" onKeyTyped="#messageTextUpdated" prefHeight="200.0" prefWidth="200.0" wrapText="true" GridPane.columnIndex="1" GridPane.rowIndex="3" />
+			</GridPane.margin>
-      <Button mnemonicParsing="true" onAction="#addContactButtonClicked" text="_Add Contacts" GridPane.halignment="CENTER" GridPane.rowIndex="3" GridPane.valignment="CENTER">
+			<padding>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</padding>
+			<contextMenu>
+				<ContextMenu anchorLocation="CONTENT_TOP_LEFT">
+					<items>
+						<MenuItem fx:id="deleteContactMenuItem"
+							mnemonicParsing="false" onAction="#deleteContact" text="Delete" />
+					</items>
+				</ContextMenu>
+			</contextMenu>
+		</ListView>
+		<Label fx:id="contactLabel" prefHeight="16.0" prefWidth="250.0"
+			text="Select a contact to chat with" GridPane.columnSpan="2">
+			<GridPane.margin>
+				<Insets left="15.0" right="5.0" top="5.0" />
+			</GridPane.margin>
+			<padding>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</padding>
+		</Label>
+		<Button fx:id="settingsButton" mnemonicParsing="true"
+			onAction="#settingsButtonClicked" text="_Settings"
+			GridPane.columnIndex="1" GridPane.columnSpan="2"
+			GridPane.halignment="RIGHT" GridPane.valignment="CENTER">
+			<GridPane.margin>
+				<Insets bottom="10.0" left="5.0" right="10.0" top="10.0" />
+			</GridPane.margin>
+			<padding>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</padding>
+		</Button>
+		<ListView fx:id="messageList" prefHeight="257.0"
+			prefWidth="465.0" GridPane.columnIndex="1" GridPane.columnSpan="2"
+			GridPane.rowIndex="1" GridPane.rowSpan="2">
+			<GridPane.margin>
+				<Insets bottom="5.0" left="5.0" right="10.0" top="5.0" />
+			</GridPane.margin>
+			<padding>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</padding>
+			<contextMenu>
+				<ContextMenu anchorLocation="CONTENT_TOP_LEFT">
+					<items>
+						<MenuItem mnemonicParsing="false" onAction="#copyMessage"
+							text="Copy" />
+						<MenuItem mnemonicParsing="false"
+							onAction="#deleteMessage" text="Delete" />
+						<MenuItem mnemonicParsing="false"
+							onAction="#forwardMessage" text="Forward" />
+						<MenuItem mnemonicParsing="false"
+							onAction="#quoteMessage" text="Quote" />
+					</items>
+				</ContextMenu>
+			</contextMenu>
+		</ListView>
+		<Button fx:id="postButton" defaultButton="true" disable="true"
+			mnemonicParsing="true" onAction="#postMessage" prefHeight="10.0"
+			prefWidth="75.0" text="_Post" GridPane.columnIndex="2"
+			GridPane.halignment="CENTER" GridPane.rowIndex="4"
+			GridPane.valignment="BOTTOM">
+			<GridPane.margin>
+				<Insets bottom="10.0" left="5.0" right="10.0" />
+			</GridPane.margin>
+			<padding>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</padding>
+			<tooltip>
+				<Tooltip anchorLocation="WINDOW_TOP_LEFT" autoHide="true"
+					maxWidth="350.0"
+					text="Click this button to send the message. If it is disabled, you first have to select a contact to send it to. A message may automatically be sent when you press (Ctrl + ) Enter, according to your preferences. Additionally sends a message when pressing &quot;Alt&quot; + &quot;P&quot;."
+					wrapText="true" />
+			</tooltip>
+			<contextMenu>
+				<ContextMenu anchorLocation="CONTENT_TOP_LEFT">
+					<items>
+						<MenuItem mnemonicParsing="false"
+							onAction="#copyAndPostMessage" text="Copy and Send" />
+					</items>
+				</ContextMenu>
+			</contextMenu>
+		</Button>
+		<TextArea fx:id="messageTextArea" disable="true"
+			onInputMethodTextChanged="#messageTextUpdated"
+			onKeyPressed="#checkPostConditions" onKeyTyped="#checkKeyCombination"
+			prefHeight="200.0" prefWidth="200.0" wrapText="true"
+			GridPane.columnIndex="1" GridPane.rowIndex="4">
+			<GridPane.margin>
+				<Insets bottom="10.0" left="5.0" right="5.0" top="5.0" />
+			</GridPane.margin>
+			<opaqueInsets>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</opaqueInsets>
+		</TextArea>
+		<Button mnemonicParsing="true"
+			onAction="#addContactButtonClicked" text="_Add Contacts"
+			GridPane.halignment="CENTER" GridPane.rowIndex="4"
+			GridPane.valignment="CENTER">
 			<padding>
 				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
 			</padding>
 			<GridPane.margin>
-            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+				<Insets bottom="5.0" left="10.0" right="5.0" top="5.0" />
 			</GridPane.margin>
 		</Button>
-      <Label fx:id="remainingChars" disable="true" ellipsisString="" maxHeight="30.0" maxWidth="180.0" prefHeight="30.0" prefWidth="180.0" text="remaining chars: 0/x" textFill="LIME" textOverrun="LEADING_WORD_ELLIPSIS" visible="false" GridPane.columnIndex="1" GridPane.rowIndex="2">
+		<Label id="remainingCharsLabel" fx:id="remainingChars"
+			ellipsisString="" maxHeight="30.0" maxWidth="180.0" prefHeight="30.0"
+			prefWidth="180.0" text="remaining chars: 0/x" textFill="LIME"
+			textOverrun="LEADING_WORD_ELLIPSIS" visible="false"
+			GridPane.columnIndex="1" GridPane.rowIndex="3">
+			<GridPane.margin>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</GridPane.margin>
+			<padding>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</padding>
+			<opaqueInsets>
+				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+			</opaqueInsets>
+			<tooltip>
+				<Tooltip
+					text="Shows how many chars you can still enter in this message"
+					wrapText="true" />
+			</tooltip>
+		</Label>
+		<Label fx:id="infoLabel" text="Something happened"
+			textFill="#faa007" visible="false" GridPane.columnIndex="1"
+			GridPane.rowIndex="1">
 			<GridPane.margin>
 				<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
 			</GridPane.margin>

src/main/resources/fxml/ContactSearchScene.fxml

@@ -23,30 +23,45 @@
                   <Tooltip text="Enter a name. If an account by that name exists, it will be displayed below." wrapText="true" />
                </tooltip>
             </TextField>
-            <Button fx:id="clearButton" disable="true" mnemonicParsing="true" onAction="#clear" text="Clea_r">
+            <Button fx:id="clearButton" disable="true" mnemonicParsing="true" onAction="#clear" prefHeight="26.0" prefWidth="110.0" text="Clea_r">
                <tooltip>
                   <Tooltip autoHide="true" text="Clears the text to the left and the elements below" wrapText="true" />
                </tooltip>
+               <HBox.margin>
+                  <Insets bottom="5.0" left="5.0" right="10.0" top="5.0" />
+               </HBox.margin>
+               <padding>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </padding>
             </Button>
-            <Button fx:id="searchButton" defaultButton="true" disable="true" mnemonicParsing="true" onAction="#suggestContacts" prefHeight="26.0" prefWidth="71.0" text="_Search" textOverrun="LEADING_WORD_ELLIPSIS">
+            <Button fx:id="searchButton" defaultButton="true" disable="true" mnemonicParsing="true" onAction="#suggestContacts" prefHeight="26.0" prefWidth="124.0" text="_Search" textOverrun="LEADING_WORD_ELLIPSIS">
                <padding>
                   <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
                </padding>
                <HBox.margin>
-                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+                  <Insets bottom="5.0" right="20.0" top="5.0" />
                </HBox.margin>
                <tooltip>
                   <Tooltip autoHide="true" text="Search for accounts with the name entered to the left" wrapText="true" />
                </tooltip>
             </Button>
-            <Button mnemonicParsing="false" onAction="#newGroupButtonClicked" text="New Group">
+            <Button mnemonicParsing="false" onAction="#newGroupButtonClicked" prefHeight="26.0" prefWidth="139.0" text="New Group">
                <HBox.margin>
-                  <Insets left="100.0" />
+                  <Insets bottom="5.0" left="20.0" right="5.0" top="5.0" />
                </HBox.margin>
+               <padding>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </padding>
             </Button>
          </children>
       </HBox>
-      <ListView fx:id="contactList" onMouseClicked="#contactListClicked" prefHeight="314.0" prefWidth="600.0" />
+      <ListView fx:id="contactList" onMouseClicked="#contactListClicked" prefHeight="314.0" prefWidth="600.0">
+         <padding>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </padding>
+         <VBox.margin>
+            <Insets bottom="10.0" left="10.0" right="10.0" top="10.0" />
+         </VBox.margin></ListView>
       <Button fx:id="backButton" cancelButton="true" mnemonicParsing="true" onAction="#backButtonClicked" text="_Back">
          <VBox.margin>
             <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />

src/main/resources/fxml/GroupCreationScene.fxml

@@ -14,7 +14,7 @@
    <children>
       <HBox alignment="CENTER" prefHeight="100.0" prefWidth="200.0">
          <children>
-            <TextField fx:id="groupNameBar" prefColumnCount="22" promptText="Enter Group Name">
+            <TextField fx:id="groupNameField" prefColumnCount="22" promptText="Enter Group Name">
                <HBox.margin>
                   <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
                </HBox.margin>
@@ -31,10 +31,28 @@
          <font>
             <Font size="16.0" />
          </font>
+         <VBox.margin>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </VBox.margin>
+         <padding>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </padding>
       </Label>
-      <ListView fx:id="contactList" prefHeight="314.0" prefWidth="600.0" />
+      <ListView fx:id="contactList" onMouseClicked="#contactListClicked" prefHeight="314.0" prefWidth="600.0">
-      <Button mnemonicParsing="false" onAction="#sendGroupObject" text="Create" />
+         <VBox.margin>
-      <Button fx:id="backButton" cancelButton="true" mnemonicParsing="true" onAction="#backButtonClicked" text="_Back">
+            <Insets bottom="5.0" left="10.0" right="10.0" top="5.0" />
+         </VBox.margin>
+         <padding>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </padding></ListView>
+      <Button fx:id="createButton" defaultButton="true" disable="true" mnemonicParsing="false" onAction="#createButtonClicked" text="Create">
+         <VBox.margin>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </VBox.margin>
+         <padding>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </padding></Button>
+      <Button cancelButton="true" mnemonicParsing="true" onAction="#backButtonClicked" text="_Back">
          <VBox.margin>
             <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
          </VBox.margin>

src/main/resources/fxml/LoginScene.fxml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
+<?import javafx.geometry.Insets?>
 <?import javafx.scene.control.Button?>
 <?import javafx.scene.control.ButtonBar?>
 <?import javafx.scene.control.CheckBox?>
@@ -12,13 +13,18 @@
 <?import javafx.scene.layout.VBox?>
 <?import javafx.scene.text.Font?>
 
-
 <VBox prefHeight="206.0" prefWidth="440.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="envoy.client.ui.controller.LoginScene">
    <children>
 				<Label text="User Login">
 					<font>
 						<Font size="26.0" />
 					</font>
+         <VBox.margin>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </VBox.margin>
+         <padding>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </padding>
 				</Label>
 				<GridPane>
 					<columnConstraints>
@@ -31,19 +37,65 @@
 						<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
 					</rowConstraints>
 					<children>
-						<Label text="User Name:" />
+						<Label text="User Name:">
-						<Label text="Password" GridPane.rowIndex="1" />
+               <GridPane.margin>
-						<Label fx:id="repeatPasswordLabel" text="Repeat Password:" visible="false" GridPane.rowIndex="2" />
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
-						<TextField fx:id="userTextField" GridPane.columnIndex="1" />
+               </GridPane.margin>
-						<PasswordField fx:id="passwordField" GridPane.columnIndex="1" GridPane.rowIndex="1" />
+               <padding>
-						<PasswordField fx:id="repeatPasswordField" promptText="Repeat the chosen password" visible="false" GridPane.columnIndex="1" GridPane.rowIndex="2" />
+                  <Insets bottom="2.0" left="2.0" right="2.0" top="2.0" />
+               </padding></Label>
+						<Label text="Password" GridPane.rowIndex="1">
+               <padding>
+                  <Insets bottom="2.0" left="2.0" right="2.0" top="2.0" />
+               </padding>
+               <GridPane.margin>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </GridPane.margin></Label>
+						<Label fx:id="repeatPasswordLabel" text="Repeat Password:" visible="false" GridPane.rowIndex="2">
+               <GridPane.margin>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </GridPane.margin>
+               <padding>
+                  <Insets bottom="2.0" left="2.0" right="2.0" top="2.0" />
+               </padding></Label>
+						<TextField fx:id="userTextField" GridPane.columnIndex="1">
+               <GridPane.margin>
+                  <Insets bottom="10.0" left="5.0" right="5.0" top="5.0" />
+               </GridPane.margin>
+               <padding>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </padding></TextField>
+						<PasswordField fx:id="passwordField" GridPane.columnIndex="1" GridPane.rowIndex="1">
+               <GridPane.margin>
+                  <Insets bottom="10.0" left="5.0" right="5.0" top="10.0" />
+               </GridPane.margin>
+               <padding>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </padding></PasswordField>
+						<PasswordField fx:id="repeatPasswordField" visible="false" GridPane.columnIndex="1" GridPane.rowIndex="2">
+               <GridPane.margin>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="10.0" />
+               </GridPane.margin>
+               <padding>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </padding></PasswordField>
 					</children>
 				</GridPane>
-				<CheckBox fx:id="registerCheckBox" mnemonicParsing="true" onAction="#registerCheckboxChanged" prefHeight="17.0" prefWidth="181.0" text="_Register" />
+				<CheckBox fx:id="registerCheckBox" mnemonicParsing="true" onAction="#registerCheckboxChanged" prefHeight="17.0" prefWidth="181.0" text="_Register">
+         <padding>
+            <Insets bottom="2.0" left="2.0" right="2.0" top="2.0" />
+         </padding>
+         <VBox.margin>
+            <Insets bottom="3.0" left="3.0" right="3.0" top="3.0" />
+         </VBox.margin></CheckBox>
       <Label fx:id="connectionLabel" />
       <ButtonBar prefHeight="40.0" prefWidth="200.0">
         <buttons>
-            <Button mnemonicParsing="false" onAction="#abortLogin" text="Close" />
+            <Button mnemonicParsing="false" onAction="#abortLogin" text="Close">
+               <padding>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </padding>
+            </Button>
             <Button mnemonicParsing="false" onAction="#offlineModeButtonPressed" text="Offline mode" />
           <Button defaultButton="true" mnemonicParsing="false" onAction="#loginButtonPressed" text="Login" />
         </buttons>

src/main/resources/fxml/SettingsScene.fxml

@@ -9,16 +9,37 @@
 
 <VBox alignment="TOP_RIGHT" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="envoy.client.ui.controller.SettingsScene">
 	<children>
-		<HBox prefHeight="100.0" prefWidth="200.0">
+		<HBox prefHeight="389.0" prefWidth="600.0">
          <children>
-            <ListView fx:id="settingsList" onMouseClicked="#settingsListClicked" prefHeight="200.0" prefWidth="200.0" />
+            <ListView fx:id="settingsList" onMouseClicked="#settingsListClicked" prefHeight="200.0" prefWidth="200.0">
-            <TitledPane fx:id="titledPane" collapsible="false" prefHeight="200.0" prefWidth="200.0" />
+               <opaqueInsets>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </opaqueInsets>
+               <HBox.margin>
+                  <Insets bottom="10.0" left="10.0" right="5.0" top="10.0" />
+               </HBox.margin>
+               <padding>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </padding></ListView>
+            <TitledPane fx:id="titledPane" collapsible="false" prefHeight="325.0" prefWidth="300.0">
+               <HBox.margin>
+                  <Insets bottom="10.0" left="5.0" right="10.0" top="10.0" />
+               </HBox.margin>
+               <padding>
+                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+               </padding></TitledPane>
          </children>
 		</HBox>
       <Button defaultButton="true" mnemonicParsing="true" onMouseClicked="#backButtonClicked" text="_Back">
          <opaqueInsets>
             <Insets />
          </opaqueInsets>
+         <padding>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </padding>
+         <VBox.margin>
+            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
+         </VBox.margin>
       </Button>
 	</children>
 </VBox>