Add Datamodel

Jenkinsfile

@@ -1,37 +0,0 @@
-pipeline {
-	agent any
-
-	options {
-		ansiColor('xterm')
-	}
-
-	stages {
-		stage('Build') {
-			steps {
-				sh 'mvn -DskipTests clean package'
-			}
-		}
-		stage('Test') {
-			steps {
-				sh 'mvn test'
-			}
-			post {
-				always {
-					junit '*/target/surefire-reports/*.xml'
-				}
-			}
-		}
-		stage('SonarQube Analysis') {
-			steps {
-				withSonarQubeEnv('KSKE SonarQube') {
-					sh 'mvn org.sonarsource.scanner.maven:sonar-maven-plugin:3.9.1.2184:sonar'
-				}
-			}
-		}
-	}
-	post {
-		success {
-			archiveArtifacts artifacts: 'client/target/envoy-client-*-shaded.jar, server/target/envoy-server-jar-with-dependencies.jar'
-		}
-	}
-}

README.md

@@ -17,8 +17,6 @@ If you want to transfer a file to another user, you can attach it to a message.
 
 On the settings page some convenience features can be configured, as well as the color theme.
 
-Additional info on how to use Envoy can be found [here](https://git.kske.dev/zdm/envoy/wiki) in the client section.
-
 ### System requirements
 
 To run Envoy, you have to install a Java Runtime Environment (JRE) of at least version 11.
@@ -31,7 +29,7 @@ Most major Linux distributions like Debian, Arch and Gentoo have a Noto emoji pa
 
 To set up an Envoy server, download the package from the release page.
 
-To configure the behavior of Envoy Server, please have a look at the [documentation](https://git.kske.dev/zdm/envoy/wiki), specifically the server part.
+Because the project lacks external documentation for the moment, please refer to the Javadoc inside the source code to configure your Envoy instance.
 
 ### System requirements
 

client/.classpath

@@ -21,6 +21,7 @@
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11">
 		<attributes>
 			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="module" value="true"/>
 		</attributes>
 	</classpathentry>
 	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">

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

@@ -22,21 +22,20 @@ import envoy.client.net.WriteProxy;
  */
 public class Chat implements Serializable {
 
-	protected transient ObservableList<Message> messages = FXCollections.observableArrayList();
-
-	protected final Contact recipient;
-
 	protected boolean disabled;
-	protected boolean	underlyingContactDeleted;
 
 	/**
 	 * Stores the last time an {@link envoy.event.IsTyping} event has been sent.
 	 */
 	protected transient long lastWritingEvent;
 
+	protected transient ObservableList<Message> messages = FXCollections.observableArrayList();
+
 	protected int						unreadAmount;
 	protected static IntegerProperty	totalUnreadAmount	= new SimpleIntegerProperty();
 
+	protected final Contact recipient;
+
 	private static final long serialVersionUID = 2L;
 
 	/**

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

@@ -13,8 +13,9 @@ import java.util.stream.Stream;
 import javafx.application.Platform;
 import javafx.collections.*;
 
-import dev.kske.eventbus.core.*;
+import dev.kske.eventbus.Event;
-import dev.kske.eventbus.core.Event;
+import dev.kske.eventbus.EventBus;
+import dev.kske.eventbus.EventListener;
 
 import envoy.data.*;
 import envoy.data.Message.MessageStatus;
@@ -34,7 +35,7 @@ import envoy.client.event.*;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public final class LocalDB {
+public final class LocalDB implements EventListener {
 
 	// Data
 	private User					user;
@@ -245,13 +246,8 @@ public final class LocalDB {
 	 * @throws IOException if the saving process failed
 	 * @since Envoy Client v0.3-alpha
 	 */
-	@Event(EnvoyCloseEvent.class)
+	@Event(eventType = EnvoyCloseEvent.class, priority = 500)
-	@Priority(500)
 	private synchronized void save() {
-
-		// Stop saving if this account has been deleted
-		if (userFile == null)
-			return;
 		EnvoyLog.getLogger(LocalDB.class).log(Level.FINER, "Saving local database...");
 
 		// Save users
@@ -277,66 +273,37 @@ public final class LocalDB {
 		}
 	}
 
-	/**
+	@Event(priority = 500)
-	 * Deletes any local remnant of this user.
-	 *
-	 * @since Envoy Client v0.3-beta
-	 */
-	public void delete() {
-		try {
-
-			// Save ID generator - can be used for other users in that db
-			if (hasIDGenerator())
-				SerializationUtils.write(idGeneratorFile, idGenerator);
-		} catch (final IOException e) {
-			EnvoyLog.getLogger(LocalDB.class).log(Level.SEVERE, "Unable to save local database: ",
-				e);
-		}
-		if (lastLoginFile != null)
-			lastLoginFile.delete();
-		userFile.delete();
-		users.remove(user.getName());
-		userFile = null;
-		onLogout();
-	}
-
-	@Event
-	@Priority(500)
 	private void onMessage(Message msg) {
 		if (msg.getStatus() == MessageStatus.SENT)
 			msg.nextStatus();
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onGroupMessage(GroupMessage msg) {
 		// TODO: Cancel event once EventBus is updated
 		if (msg.getStatus() == MessageStatus.WAITING || msg.getStatus() == MessageStatus.READ)
 			logger.warning("The groupMessage has the unexpected status " + msg.getStatus());
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onMessageStatusChange(MessageStatusChange evt) {
 		getMessage(evt.getID()).ifPresent(msg -> msg.setStatus(evt.get()));
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onGroupMessageStatusChange(GroupMessageStatusChange evt) {
 		this.<GroupMessage>getMessage(evt.getID())
 			.ifPresent(msg -> msg.getMemberStatuses().replace(evt.getMemberID(), evt.get()));
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onUserStatusChange(UserStatusChange evt) {
 		getChat(evt.getID()).map(Chat::getRecipient).map(User.class::cast)
 			.ifPresent(u -> u.setStatus(evt.get()));
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onUserOperation(UserOperation operation) {
 		final var eventUser = operation.get();
 		switch (operation.getOperationType()) {
@@ -362,15 +329,13 @@ public final class LocalDB {
 			Platform.runLater(() -> chats.add(new GroupChat(user, newGroup)));
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onGroupResize(GroupResize evt) {
 		getChat(evt.getGroupID()).map(Chat::getRecipient).map(Group.class::cast)
 			.ifPresent(evt::apply);
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onNameChange(NameChange evt) {
 		chats.stream().map(Chat::getRecipient).filter(c -> c.getID() == evt.getID()).findAny()
 			.ifPresent(c -> c.setName(evt.get()));
@@ -392,8 +357,7 @@ public final class LocalDB {
 	 *
 	 * @since Envoy Client v0.2-beta
 	 */
-	@Event(Logout.class)
+	@Event(eventType = Logout.class, priority = 50)
-	@Priority(50)
 	private void onLogout() {
 		autoSaver.cancel();
 		autoSaveRestart = true;
@@ -425,33 +389,21 @@ public final class LocalDB {
 		});
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onOwnStatusChange(OwnStatusChange statusChange) {
 		user.setStatus(statusChange.get());
 	}
 
-	@Event(ContactsChangedSinceLastLogin.class)
+	@Event(eventType = ContactsChangedSinceLastLogin.class, priority = 500)
-	@Priority(500)
 	private void onContactsChangedSinceLastLogin() {
 		contactsChanged = true;
 	}
 
-	@Event
+	@Event(priority = 500)
-	@Priority(500)
 	private void onContactDisabled(ContactDisabled event) {
 		getChat(event.get().getID()).ifPresent(chat -> chat.setDisabled(true));
 	}
 
-	@Event
-	@Priority(500)
-	private void onAccountDeletion(AccountDeletion deletion) {
-		if (user.getID() == deletion.get())
-			logger.log(Level.WARNING,
-				"I have been informed by the server that I have been deleted without even knowing it...");
-		getChat(deletion.get()).ifPresent(chat -> chat.setDisabled(true));
-	}
-
 	/**
 	 * @return a {@code Map<String, User>} of all users stored locally with their user names as keys
 	 * @since Envoy Client v0.2-alpha
@@ -509,8 +461,7 @@ public final class LocalDB {
 	 * @param idGenerator the message ID generator to set
 	 * @since Envoy Client v0.3-alpha
 	 */
-	@Event
+	@Event(priority = 150)
-	@Priority(150)
 	public void setIDGenerator(IDGenerator idGenerator) { this.idGenerator = idGenerator; }
 
 	/**

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

@@ -5,7 +5,8 @@ import java.util.*;
 import java.util.logging.Level;
 import java.util.prefs.Preferences;
 
-import dev.kske.eventbus.core.*;
+import dev.kske.eventbus.*;
+import dev.kske.eventbus.EventListener;
 
 import envoy.util.*;
 
@@ -20,7 +21,7 @@ import envoy.client.event.EnvoyCloseEvent;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.2-alpha
  */
-public final class Settings {
+public final class Settings implements EventListener {
 
 	// Actual settings accessible by the rest of the application
 	private Map<String, SettingsItem<?>> items;
@@ -68,7 +69,7 @@ public final class Settings {
 	 * @throws IOException if an error occurs while saving the themes
 	 * @since Envoy Client v0.2-alpha
 	 */
-	@Event(EnvoyCloseEvent.class)
+	@Event(eventType = EnvoyCloseEvent.class)
 	private void save() {
 		EnvoyLog.getLogger(Settings.class).log(Level.INFO, "Saving settings...");
 

client/src/main/java/envoy/client/data/shortcuts/EnvoyShortcutConfig.java

@@ -6,7 +6,7 @@ import envoy.data.User.UserStatus;
 
 import envoy.client.data.Context;
 import envoy.client.helper.ShutdownHelper;
-import envoy.client.ui.SceneInfo;
+import envoy.client.ui.SceneContext.SceneInfo;
 import envoy.client.util.UserUtil;
 
 /**

client/src/main/java/envoy/client/data/shortcuts/GlobalKeyShortcuts.java

@@ -4,7 +4,7 @@ import java.util.*;
 
 import javafx.scene.input.KeyCombination;
 
-import envoy.client.ui.SceneInfo;
+import envoy.client.ui.SceneContext.SceneInfo;
 
 /**
  * Contains all keyboard shortcuts used throughout the application.

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

@@ -1,22 +0,0 @@
-package envoy.client.event;
-
-import envoy.event.Event;
-
-/**
- * Signifies the deletion of an account.
- * 
- * @author Leon Hofmeister
- * @since Envoy Common v0.3-beta
- */
-public class AccountDeletion extends Event<Long> {
-
-	private static final long serialVersionUID = 1L;
-
-	/**
-	 * @param value the ID of the contact that was deleted
-	 * @since Envoy Common v0.3-beta
-	 */
-	public AccountDeletion(Long value) {
-		super(value);
-	}
-}

client/src/main/java/envoy/client/helper/ShutdownHelper.java

@@ -1,6 +1,6 @@
 package envoy.client.helper;
 
-import dev.kske.eventbus.core.EventBus;
+import dev.kske.eventbus.EventBus;
 
 import envoy.client.data.*;
 import envoy.client.event.EnvoyCloseEvent;

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

@@ -5,14 +5,14 @@ import java.net.Socket;
 import java.util.concurrent.TimeoutException;
 import java.util.logging.*;
 
-import dev.kske.eventbus.core.*;
+import dev.kske.eventbus.*;
-import dev.kske.eventbus.core.Event;
+import dev.kske.eventbus.Event;
 
 import envoy.data.*;
 import envoy.event.*;
 import envoy.util.*;
 
-import envoy.client.data.ClientConfig;
+import envoy.client.data.*;
 import envoy.client.event.EnvoyCloseEvent;
 
 /**
@@ -24,7 +24,7 @@ import envoy.client.event.EnvoyCloseEvent;
  * @author Leon Hofmeister
  * @since Envoy Client v0.1-alpha
  */
-public final class Client implements Closeable {
+public final class Client implements EventListener, Closeable {
 
 	// Connection handling
 	private Socket		socket;
@@ -55,12 +55,13 @@ public final class Client implements Closeable {
 	 * the handshake does exceed this time limit, an exception is thrown.
 	 *
 	 * @param credentials the login credentials of the user
+	 * @param cacheMap    the map of all caches needed
 	 * @throws TimeoutException     if the server could not be reached
 	 * @throws IOException          if the login credentials could not be written
 	 * @throws InterruptedException if the current thread is interrupted while waiting for the
 	 *                              handshake response
 	 */
-	public void performHandshake(LoginCredentials credentials)
+	public void performHandshake(LoginCredentials credentials, CacheMap cacheMap)
 		throws TimeoutException, IOException, InterruptedException {
 		if (online)
 			throw new IllegalStateException("Handshake has already been performed successfully");
@@ -78,6 +79,7 @@ public final class Client implements Closeable {
 		// Register user creation processor, contact list processor, message cache and
 		// authentication token
 		receiver.registerProcessor(User.class, sender -> this.sender = sender);
+		receiver.registerProcessors(cacheMap.getMap());
 
 		// Start receiver
 		receiver.start();
@@ -99,20 +101,44 @@ public final class Client implements Closeable {
 
 			if (System.currentTimeMillis() - start > 5000) {
 				rejected = true;
-				socket.close();
-				receiver.removeAllProcessors();
 				throw new TimeoutException("Did not log in after 5 seconds");
 			}
 			Thread.sleep(500);
 		}
 
-		// Remove handshake specific processors
-		receiver.removeAllProcessors();
-
 		online = true;
 		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 {@link IDGenerator}
+	 * @param cacheMap the map of all caches needed
+	 * @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, CacheMap cacheMap) throws IOException {
+		checkOnline();
+
+		// Remove all processors as they are only used during the handshake
+		receiver.removeAllProcessors();
+
+		// Relay cached messages and message status changes
+		cacheMap.get(Message.class).setProcessor(eventBus::dispatch);
+		cacheMap.get(GroupMessage.class).setProcessor(eventBus::dispatch);
+		cacheMap.get(MessageStatusChange.class).setProcessor(eventBus::dispatch);
+		cacheMap.get(GroupMessageStatusChange.class).setProcessor(eventBus::dispatch);
+
+		// Request a generator if none is present or the existing one is consumed
+		if (!localDB.hasIDGenerator() || !localDB.getIDGenerator().hasNext())
+			requestIDGenerator();
+
+		// Relay caches
+		cacheMap.getMap().values().forEach(Cache::relay);
+	}
+
 	/**
 	 * Sends an object to the server.
 	 *
@@ -153,15 +179,13 @@ public final class Client implements Closeable {
 		send(new IDGeneratorRequest());
 	}
 
-	@Event(HandshakeRejection.class)
+	@Event(eventType = HandshakeRejection.class, priority = 1000)
-	@Priority(1000)
 	private void onHandshakeRejection() {
 		rejected = true;
 	}
 
 	@Override
-	@Event(EnvoyCloseEvent.class)
+	@Event(eventType = EnvoyCloseEvent.class, priority = 50)
-	@Priority(50)
 	public void close() {
 		if (online) {
 			logger.log(Level.INFO, "Closing connection...");

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

@@ -6,7 +6,7 @@ import java.util.*;
 import java.util.function.Consumer;
 import java.util.logging.*;
 
-import dev.kske.eventbus.core.EventBus;
+import dev.kske.eventbus.*;
 
 import envoy.util.*;
 
@@ -87,17 +87,15 @@ public final class Receiver extends Thread {
 					// Dispatch to the processor if present
 					if (processor != null)
 						processor.accept(obj);
-					// Dispatch to the event bus if the object has no processor
+					// Dispatch to the event bus if the object is an event without a processor
-					else
+					else if (obj instanceof IEvent)
-						eventBus.dispatch(obj);
+						eventBus.dispatch((IEvent) obj);
-
-					// TODO: Log DeadEvent from Event Bus 1.1.0
 					// Notify if no processor could be located
-					// else
+					else
-					// logger.log(Level.WARNING,
+						logger.log(Level.WARNING,
-					// String.format(
+							String.format(
-					// "The received object has the %s for which no processor is defined.",
+								"The received object has the %s for which no processor is defined.",
-					// obj.getClass()));
+								obj.getClass()));
 				}
 			} catch (final SocketException | EOFException e) {
 				// Connection probably closed by client.

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

@@ -4,11 +4,12 @@ import java.io.IOException;
 import java.util.Stack;
 import java.util.logging.Level;
 
+import javafx.application.Platform;
 import javafx.fxml.FXMLLoader;
 import javafx.scene.*;
 import javafx.stage.Stage;
 
-import dev.kske.eventbus.core.*;
+import dev.kske.eventbus.*;
 
 import envoy.util.EnvoyLog;
 
@@ -25,13 +26,53 @@ import envoy.client.event.*;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
  */
-public final class SceneContext {
+public final class SceneContext implements EventListener {
+
+	/**
+	 * Contains information about different scenes and their FXML resource files.
+	 *
+	 * @author Kai S. K. Engelbart
+	 * @since Envoy Client v0.1-beta
+	 */
+	public enum SceneInfo {
+
+		/**
+		 * The main scene in which the chat screen is displayed.
+		 *
+		 * @since Envoy Client v0.1-beta
+		 */
+		CHAT_SCENE("/fxml/ChatScene.fxml"),
+
+		/**
+		 * The scene in which the settings screen is displayed.
+		 *
+		 * @since Envoy Client v0.1-beta
+		 */
+		SETTINGS_SCENE("/fxml/SettingsScene.fxml"),
+
+		/**
+		 * The scene in which the login screen is displayed.
+		 *
+		 * @since Envoy Client v0.1-beta
+		 */
+		LOGIN_SCENE("/fxml/LoginScene.fxml");
+
+		/**
+		 * The path to the FXML resource.
+		 */
+		public final String path;
+
+		SceneInfo(String path) {
+			this.path = path;
+		}
+	}
 
 	private final Stage			stage;
-	private final Stack<Parent>	roots		= new Stack<>();
+	private final FXMLLoader	loader			= new FXMLLoader();
-	private final Stack<Object>	controllers	= new Stack<>();
+	private final Stack<Scene>	sceneStack		= new Stack<>();
+	private final Stack<Object>	controllerStack	= new Stack<>();
 
-	private Scene scene;
+	private static final Settings settings = Settings.getInstance();
 
 	/**
 	 * Initializes the scene context.
@@ -47,44 +88,44 @@ public final class SceneContext {
 	/**
 	 * Loads a new scene specified by a scene info.
 	 *
-	 * @param info specifies the scene to load
+	 * @param sceneInfo specifies the scene to load
 	 * @throws RuntimeException if the loading process fails
 	 * @since Envoy Client v0.1-beta
 	 */
-	public void load(SceneInfo info) {
+	public void load(SceneInfo sceneInfo) {
-		EnvoyLog.getLogger(SceneContext.class).log(Level.FINER, "Loading scene " + info);
+		EnvoyLog.getLogger(SceneContext.class).log(Level.FINER, "Loading scene " + sceneInfo);
+		loader.setRoot(null);
+		loader.setController(null);
 
 		try {
+			final var	rootNode	=
+				(Parent) loader.load(getClass().getResourceAsStream(sceneInfo.path));
+			final var	scene		= new Scene(rootNode);
+			final var	controller	= loader.getController();
+			controllerStack.push(controller);
 
-			// Load root node and controller
+			sceneStack.push(scene);
-			var		loader		= new FXMLLoader();
-			Parent	root		= loader.load(getClass().getResourceAsStream(info.path));
-			Object	controller	= loader.getController();
-			roots.push(root);
-			controllers.push(controller);
-
-			if (scene == null) {
-
-				// One-time scene initialization
-				scene = new Scene(root, stage.getWidth(), stage.getHeight());
-				applyCSS();
 			stage.setScene(scene);
-			} else {
-				scene.setRoot(root);
-			}
-
-			// Remove previous keyboard shortcuts
-			scene.getAccelerators().clear();
 
 			// Supply the global custom keyboard shortcuts for that scene
 			scene.getAccelerators()
-				.putAll(GlobalKeyShortcuts.getInstance().getKeyboardShortcuts(info));
+				.putAll(GlobalKeyShortcuts.getInstance().getKeyboardShortcuts(sceneInfo));
 
 			// Supply the scene specific keyboard shortcuts
 			if (controller instanceof KeyboardMapping)
 				scene.getAccelerators()
 					.putAll(((KeyboardMapping) controller).getKeyboardShortcuts());
-		} catch (IOException e) {
+
+			// The LoginScene is the only scene not intended to be resized
+			// As strange as it seems, this is needed as otherwise the LoginScene won't be
+			// displayed on some OS (...Debian...)
+			stage.sizeToScene();
+			Platform.runLater(() -> stage.setResizable(sceneInfo != SceneInfo.LOGIN_SCENE));
+			applyCSS();
+			stage.show();
+		} 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);
 		}
 	}
@@ -96,45 +137,42 @@ public final class SceneContext {
 	 */
 	public void pop() {
 
-		// Pop current root node and controller
+		// Pop scene and controller
-		roots.pop();
+		sceneStack.pop();
-		controllers.pop();
+		controllerStack.pop();
 
 		// Apply new scene if present
-		if (!roots.isEmpty()) {
+		if (!sceneStack.isEmpty()) {
-			scene.setRoot(roots.peek());
+			final var newScene = sceneStack.peek();
-
+			stage.setScene(newScene);
-			// Invoke restore if controller is restorable
+			applyCSS();
-			var controller = controllers.peek();
+			stage.sizeToScene();
+			// If the controller implements the Restorable interface,
+			// the actions to perform on restoration will be executed here
+			final var controller = controllerStack.peek();
 			if (controller instanceof Restorable)
 				((Restorable) controller).onRestore();
-		} else {
-
-			// Remove the current scene entirely
-			scene = null;
-			stage.setScene(null);
 		}
+		stage.show();
 	}
 
 	private void applyCSS() {
-		if (scene != null) {
+		if (!sceneStack.isEmpty()) {
-			var	styleSheets	= scene.getStylesheets();
+			final var	styleSheets	= stage.getScene().getStylesheets();
-			var	themeCSS	= "/css/" + Settings.getInstance().getCurrentTheme() + ".css";
+			final var	themeCSS	= "/css/" + settings.getCurrentTheme() + ".css";
 			styleSheets.clear();
 			styleSheets.addAll(getClass().getResource("/css/base.css").toExternalForm(),
 				getClass().getResource(themeCSS).toExternalForm());
 		}
 	}
 
-	@Event(Logout.class)
+	@Event(eventType = Logout.class, priority = 150)
-	@Priority(150)
 	private void onLogout() {
-		roots.clear();
+		sceneStack.clear();
-		controllers.clear();
+		controllerStack.clear();
 	}
 
-	@Event(ThemeChangeEvent.class)
+	@Event(priority = 150, eventType = ThemeChangeEvent.class)
-	@Priority(150)
 	private void onThemeChange() {
 		applyCSS();
 	}
@@ -144,7 +182,7 @@ public final class SceneContext {
 	 * @return the controller used by the current scene
 	 * @since Envoy Client v0.1-beta
 	 */
-	public <T> T getController() { return (T) controllers.peek(); }
+	public <T> T getController() { return (T) controllerStack.peek(); }
 
 	/**
 	 * @return the stage in which the scenes are displayed
@@ -156,5 +194,5 @@ public final class SceneContext {
 	 * @return whether the scene stack is empty
 	 * @since Envoy Client v0.2-beta
 	 */
-	public boolean isEmpty() { return roots.isEmpty(); }
+	public boolean isEmpty() { return sceneStack.isEmpty(); }
 }

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

@@ -1,40 +0,0 @@
-package envoy.client.ui;
-
-/**
- * Contains information about different scenes and their FXML resource files.
- *
- * @author Kai S. K. Engelbart
- * @since Envoy Client v0.1-beta
- */
-public enum SceneInfo {
-
-	/**
-	 * The main scene in which the chat screen is displayed.
-	 *
-	 * @since Envoy Client v0.1-beta
-	 */
-	CHAT_SCENE("/fxml/ChatScene.fxml"),
-
-	/**
-	 * The scene in which the settings screen is displayed.
-	 *
-	 * @since Envoy Client v0.1-beta
-	 */
-	SETTINGS_SCENE("/fxml/SettingsScene.fxml"),
-
-	/**
-	 * The scene in which the login screen is displayed.
-	 *
-	 * @since Envoy Client v0.1-beta
-	 */
-	LOGIN_SCENE("/fxml/LoginScene.fxml");
-
-	/**
-	 * The path to the FXML resource.
-	 */
-	public final String path;
-
-	SceneInfo(String path) {
-		this.path = path;
-	}
-}

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

@@ -12,7 +12,7 @@ import javafx.stage.Stage;
 
 import envoy.data.*;
 import envoy.data.User.UserStatus;
-import envoy.event.UserStatusChange;
+import envoy.event.*;
 import envoy.exception.EnvoyException;
 import envoy.util.EnvoyLog;
 
@@ -20,6 +20,7 @@ import envoy.client.data.*;
 import envoy.client.data.shortcuts.EnvoyShortcutConfig;
 import envoy.client.helper.ShutdownHelper;
 import envoy.client.net.Client;
+import envoy.client.ui.SceneContext.SceneInfo;
 import envoy.client.ui.controller.LoginScene;
 import envoy.client.util.IconUtil;
 
@@ -93,7 +94,7 @@ public final class Startup extends Application {
 		final var sceneContext = new SceneContext(stage);
 		context.setSceneContext(sceneContext);
 
-		// Authenticate with token if present or load login scene
+		// Authenticate with token if present
 		if (localDB.getAuthToken() != null) {
 			logger.info("Attempting authentication with token...");
 			localDB.loadUserData();
@@ -102,9 +103,8 @@ public final class Startup extends Application {
 					VERSION, localDB.getLastSync())))
 				sceneContext.load(SceneInfo.LOGIN_SCENE);
 		} else
+			// Load login scene
 			sceneContext.load(SceneInfo.LOGIN_SCENE);
-
-		stage.show();
 	}
 
 	/**
@@ -115,20 +115,21 @@ public final class Startup extends Application {
 	 * @since Envoy Client v0.2-beta
 	 */
 	public static boolean performHandshake(LoginCredentials credentials) {
+		final var cacheMap = new CacheMap();
+		cacheMap.put(Message.class, new Cache<Message>());
+		cacheMap.put(GroupMessage.class, new Cache<GroupMessage>());
+		cacheMap.put(MessageStatusChange.class, new Cache<MessageStatusChange>());
+		cacheMap.put(GroupMessageStatusChange.class, new Cache<GroupMessageStatusChange>());
 		final var originalStatus =
 			localDB.getUser() == null ? UserStatus.ONLINE : localDB.getUser().getStatus();
 		try {
-			client.performHandshake(credentials);
+			client.performHandshake(credentials, cacheMap);
 			if (client.isOnline()) {
 
 				// Restore the original status as the server automatically returns status ONLINE
 				client.getSender().setStatus(originalStatus);
 				loadChatScene();
-
+				client.initReceiver(localDB, cacheMap);
-				// Request an ID generator if none is present or the existing one is consumed
-				if (!localDB.hasIDGenerator() || !localDB.getIDGenerator().hasNext())
-					client.requestIDGenerator();
-
 				return true;
 			} else
 				return false;
@@ -225,7 +226,7 @@ public final class Startup extends Application {
 		// Load ChatScene
 		stage.setMinHeight(400);
 		stage.setMinWidth(843);
-		context.getSceneContext().load(SceneInfo.CHAT_SCENE);
+		context.getSceneContext().load(SceneContext.SceneInfo.CHAT_SCENE);
 		stage.centerOnScreen();
 
 		// Exit or minimize the stage when a close request occurs

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

@@ -9,8 +9,8 @@ import java.awt.image.BufferedImage;
 import javafx.application.Platform;
 import javafx.stage.Stage;
 
-import dev.kske.eventbus.core.Event;
+import dev.kske.eventbus.*;
-import dev.kske.eventbus.core.EventBus;
+import dev.kske.eventbus.Event;
 
 import envoy.data.Message;
 import envoy.data.User.UserStatus;
@@ -31,7 +31,7 @@ import envoy.client.util.*;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.2-alpha
  */
-public final class StatusTrayIcon {
+public final class StatusTrayIcon implements EventListener {
 
 	/**
 	 * The {@link TrayIcon} provided by the System Tray API for controlling the system tray. This
@@ -136,7 +136,7 @@ public final class StatusTrayIcon {
 	 *
 	 * @since Envoy Client v0.2-beta
 	 */
-	@Event(Logout.class)
+	@Event(eventType = Logout.class)
 	public void hide() {
 		SystemTray.getSystemTray().remove(trayIcon);
 	}

client/src/main/java/envoy/client/ui/chatscene/ChatSceneCommands.java

@@ -15,7 +15,7 @@ import envoy.util.EnvoyLog;
 import envoy.client.data.Context;
 import envoy.client.data.commands.*;
 import envoy.client.helper.ShutdownHelper;
-import envoy.client.ui.SceneInfo;
+import envoy.client.ui.SceneContext.SceneInfo;
 import envoy.client.ui.controller.ChatScene;
 import envoy.client.util.*;
 
@@ -32,7 +32,7 @@ public final class ChatSceneCommands {
 	private final SystemCommandBuilder	builder					=
 		new SystemCommandBuilder(messageTextAreaCommands);
 
-	private static final String messageDependentCommandDescription =
+	private static final String messageDependantCommandDescription =
 		" the given message. Use s/S to use the selected message. Otherwise expects a number relative to the uppermost completely visible message.";
 
 	/**
@@ -141,7 +141,7 @@ public final class ChatSceneCommands {
 			else
 				useRelativeMessage(command, action, additionalCheck, positionalArgument, false);
 		}).setDefaults("s").setNumberOfArguments(1)
-			.setDescription(description.concat(messageDependentCommandDescription)).build(command);
+			.setDescription(description.concat(messageDependantCommandDescription)).build(command);
 	}
 
 	private void selectionNeighbor(Consumer<Message> action, Predicate<Message> additionalCheck,

client/src/main/java/envoy/client/ui/control/ChatControl.java

@@ -18,7 +18,7 @@ import envoy.client.util.IconUtil;
  */
 public final class ChatControl extends HBox {
 
-	private static Image userIcon = IconUtil.loadIconThemeSensitive("user_icon", 32),
+	private static final Image userIcon = IconUtil.loadIconThemeSensitive("user_icon", 32),
 		groupIcon = IconUtil.loadIconThemeSensitive("group_icon", 32);
 
 	/**
@@ -60,14 +60,4 @@ public final class ChatControl extends HBox {
 		}
 		getStyleClass().add("list-element");
 	}
-
-	/**
-	 * Reloads the default icons.
-	 *
-	 * @since Envoy Client v0.3-beta
-	 */
-	public static void reloadDefaultChatIcons() {
-		userIcon	= IconUtil.loadIconThemeSensitive("user_icon", 32);
-		groupIcon	= IconUtil.loadIconThemeSensitive("group_icon", 32);
-	}
 }

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

@@ -1,14 +1,11 @@
 package envoy.client.ui.controller;
 
-import static envoy.client.ui.SceneInfo.SETTINGS_SCENE;
-
 import java.awt.Toolkit;
 import java.awt.datatransfer.StringSelection;
 import java.io.*;
 import java.nio.file.Files;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
-import java.util.Map;
 import java.util.logging.*;
 
 import javafx.animation.RotateTransition;
@@ -21,14 +18,14 @@ import javafx.scene.control.*;
 import javafx.scene.control.Alert.AlertType;
 import javafx.scene.image.*;
 import javafx.scene.input.*;
-import javafx.scene.layout.HBox;
+import javafx.scene.layout.*;
 import javafx.scene.paint.Color;
 import javafx.scene.shape.Rectangle;
 import javafx.stage.FileChooser;
 import javafx.util.Duration;
 
-import dev.kske.eventbus.core.*;
+import dev.kske.eventbus.*;
-import dev.kske.eventbus.core.Event;
+import dev.kske.eventbus.Event;
 
 import envoy.data.*;
 import envoy.data.Attachment.AttachmentType;
@@ -40,7 +37,6 @@ import envoy.util.EnvoyLog;
 
 import envoy.client.data.*;
 import envoy.client.data.audio.AudioRecorder;
-import envoy.client.data.shortcuts.KeyboardMapping;
 import envoy.client.event.*;
 import envoy.client.net.*;
 import envoy.client.ui.*;
@@ -55,7 +51,7 @@ import envoy.client.util.*;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
  */
-public final class ChatScene implements Restorable, KeyboardMapping {
+public final class ChatScene implements EventListener, Restorable {
 
 	@FXML
 	private ListView<Message> messageList;
@@ -220,13 +216,12 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 		});
 	}
 
-	@Event(BackEvent.class)
+	@Event(eventType = BackEvent.class)
 	private void onBackEvent() {
 		tabPane.getSelectionModel().select(Tabs.CONTACT_LIST.ordinal());
 	}
 
-	@Event
+	@Event(includeSubtypes = true)
-	@Polymorphic
 	private void onMessage(Message message) {
 
 		// The sender of the message is the recipient of the chat
@@ -305,7 +300,7 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 		}));
 	}
 
-	@Event(NoAttachments.class)
+	@Event(eventType = NoAttachments.class)
 	private void onNoAttachments() {
 		Platform.runLater(() -> {
 			attachmentButton.setDisable(true);
@@ -318,15 +313,13 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 		});
 	}
 
-	@Event
+	@Event(priority = 150)
-	@Priority(150)
 	private void onGroupCreationResult(GroupCreationResult result) {
 		Platform.runLater(() -> newGroupButton.setDisable(result.get() == null));
 	}
 
-	@Event(ThemeChangeEvent.class)
+	@Event(eventType = ThemeChangeEvent.class)
 	private void onThemeChange() {
-		ChatControl.reloadDefaultChatIcons();
 		settingsButton.setGraphic(
 			new ImageView(IconUtil.loadIconThemeSensitive("settings", DEFAULT_ICON_SIZE)));
 		voiceButton.setGraphic(
@@ -348,17 +341,11 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 				recipientProfilePic.setImage(IconUtil.loadIconThemeSensitive("group_icon", 43));
 	}
 
-	@Event(Logout.class)
+	@Event(eventType = Logout.class, priority = 200)
-	@Priority(200)
 	private void onLogout() {
 		eventBus.removeListener(this);
 	}
 
-	@Event(AccountDeletion.class)
-	private void onAccountDeletion() {
-		Platform.runLater(chatList::refresh);
-	}
-
 	@Override
 	public void onRestore() {
 		updateRemainingCharsLabel();
@@ -451,7 +438,7 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 	 */
 	@FXML
 	private void settingsButtonClicked() {
-		sceneContext.load(SETTINGS_SCENE);
+		sceneContext.load(SceneContext.SceneInfo.SETTINGS_SCENE);
 	}
 
 	/**
@@ -599,7 +586,7 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 		// IsTyping#millisecondsActive
 		if (client.isOnline() && currentChat.getLastWritingEvent()
 			+ IsTyping.millisecondsActive <= System.currentTimeMillis()) {
-			client.send(new IsTyping(currentChat.getRecipient().getID()));
+			client.send(new IsTyping(getChatID(), currentChat.getRecipient().getID()));
 			currentChat.lastWritingEventWasNow();
 		}
 
@@ -613,6 +600,19 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 			checkPostConditions(false);
 	}
 
+	/**
+	 * Returns the id that should be used to send things to the server: the id of 'our' {@link User}
+	 * if the recipient of that object is another User, else the id of the {@link Group} 'our' user
+	 * is sending to.
+	 *
+	 * @return an id that can be sent to the server
+	 * @since Envoy Client v0.2-beta
+	 */
+	private long getChatID() {
+		return currentChat.getRecipient() instanceof User ? client.getSender().getID()
+			: currentChat.getRecipient().getID();
+	}
+
 	/**
 	 * @param e the keys that have been pressed
 	 * @since Envoy Client v0.1-beta
@@ -786,8 +786,7 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 		attachmentView.setVisible(visible);
 	}
 
-	@Event(OwnStatusChange.class)
+	@Event(eventType = OwnStatusChange.class, priority = 50)
-	@Priority(50)
 	private void generateOwnStatusControl() {
 
 		// Update the own user status if present
@@ -798,7 +797,7 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 			// Else prepend it to the HBox children
 			final var ownUserControl = new ContactControl(localDB.getUser());
 			ownUserControl.setAlignment(Pos.CENTER_LEFT);
-			HBox.setHgrow(ownUserControl, javafx.scene.layout.Priority.NEVER);
+			HBox.setHgrow(ownUserControl, Priority.NEVER);
 			ownContactControl.getChildren().add(1, ownUserControl);
 		}
 	}
@@ -885,25 +884,4 @@ public final class ChatScene implements Restorable, KeyboardMapping {
 			: c -> c.getRecipient().getName().toLowerCase()
 				.contains(contactSearch.getText().toLowerCase()));
 	}
-
-	@Override
-	public Map<KeyCombination, Runnable> getKeyboardShortcuts() {
-		return Map.<KeyCombination, Runnable>of(
-
-			// Delete text before the caret with "Control" + U
-			new KeyCodeCombination(KeyCode.U, KeyCombination.CONTROL_DOWN), () -> {
-				messageTextArea
-					.setText(
-						messageTextArea.getText().substring(messageTextArea.getCaretPosition()));
-				checkPostConditions(false);
-
-				// Delete text after the caret with "Control" + K
-			}, new KeyCodeCombination(KeyCode.K, KeyCombination.CONTROL_DOWN), () -> {
-				messageTextArea
-					.setText(
-						messageTextArea.getText().substring(0, messageTextArea.getCaretPosition()));
-				checkPostConditions(false);
-				messageTextArea.positionCaret(messageTextArea.getText().length());
-			});
-	}
 }

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

@@ -7,7 +7,7 @@ import javafx.fxml.FXML;
 import javafx.scene.control.*;
 import javafx.scene.control.Alert.AlertType;
 
-import dev.kske.eventbus.core.*;
+import dev.kske.eventbus.*;
 
 import envoy.data.User;
 import envoy.event.ElementOperation;
@@ -34,7 +34,7 @@ import envoy.client.ui.listcell.ListCellFactory;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-beta
  */
-public class ContactSearchTab {
+public class ContactSearchTab implements EventListener {
 
 	@FXML
 	private TextArea searchBar;

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

@@ -10,7 +10,7 @@ import javafx.scene.control.*;
 import javafx.scene.input.MouseEvent;
 import javafx.scene.layout.HBox;
 
-import dev.kske.eventbus.core.*;
+import dev.kske.eventbus.*;
 
 import envoy.data.*;
 import envoy.event.GroupCreation;
@@ -18,7 +18,7 @@ import envoy.event.contact.UserOperation;
 import envoy.util.Bounds;
 
 import envoy.client.data.*;
-import envoy.client.event.*;
+import envoy.client.event.BackEvent;
 import envoy.client.ui.control.*;
 import envoy.client.ui.listcell.ListCellFactory;
 
@@ -33,7 +33,7 @@ import envoy.client.ui.listcell.ListCellFactory;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-beta
  */
-public class GroupCreationTab {
+public class GroupCreationTab implements EventListener {
 
 	@FXML
 	private Button createButton;
@@ -252,10 +252,4 @@ public class GroupCreationTab {
 			}
 		});
 	}
-
-	@Event
-	private void onAccountDeletion(AccountDeletion deletion) {
-		final var deletedID = deletion.get();
-		Platform.runLater(() -> userList.getItems().removeIf(user -> (user.getID() == deletedID)));
-	}
 }

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

@@ -10,7 +10,7 @@ import javafx.scene.control.*;
 import javafx.scene.control.Alert.AlertType;
 import javafx.scene.image.ImageView;
 
-import dev.kske.eventbus.core.*;
+import dev.kske.eventbus.*;
 
 import envoy.data.LoginCredentials;
 import envoy.event.HandshakeRejection;
@@ -27,7 +27,7 @@ import envoy.client.util.IconUtil;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-beta
  */
-public final class LoginScene {
+public final class LoginScene implements EventListener {
 
 	@FXML
 	private TextField userTextField;

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

@@ -2,7 +2,7 @@ package envoy.client.ui.settings;
 
 import javafx.scene.control.*;
 
-import dev.kske.eventbus.core.EventBus;
+import dev.kske.eventbus.EventBus;
 
 import envoy.data.User.UserStatus;
 

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

@@ -13,15 +13,14 @@ import javafx.scene.image.*;
 import javafx.scene.input.InputEvent;
 import javafx.scene.layout.HBox;
 import javafx.stage.FileChooser;
-import javafx.util.Duration;
 
-import dev.kske.eventbus.core.EventBus;
+import dev.kske.eventbus.EventBus;
 
 import envoy.event.*;
 import envoy.util.*;
 
 import envoy.client.ui.control.ProfilePicImageView;
-import envoy.client.util.*;
+import envoy.client.util.IconUtil;
 
 /**
  * @author Leon Hofmeister
@@ -39,7 +38,6 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 	private final PasswordField	newPasswordField		= new PasswordField();
 	private final PasswordField	repeatNewPasswordField	= new PasswordField();
 	private final Button		saveButton				= new Button("Save");
-	private final Button		deleteAccountButton		= new Button("Delete Account (Locally)");
 
 	private static final EventBus	eventBus	= EventBus.getInstance();
 	private static final Logger		logger		= EnvoyLog.getLogger(UserSettingsPane.class);
@@ -114,18 +112,15 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 
 		final PasswordField[]					passwordFields	=
 			{ currentPasswordField, newPasswordField, repeatNewPasswordField };
-		final EventHandler<? super InputEvent>	passwordEntered	=
+		final EventHandler<? super InputEvent>	passwordEntered	= e -> {
-			e -> {
 																	newPassword		=
-																			newPasswordField
+																		newPasswordField.getText();
-																				.getText();
+																	validPassword	= newPassword
-																		validPassword =
+																		.equals(
-																			newPassword.equals(
 																			repeatNewPasswordField
 																				.getText())
 																		&& !newPasswordField
-																					.getText()
+																			.getText().isBlank();
-																					.isBlank();
 																};
 		newPasswordField.setOnInputMethodTextChanged(passwordEntered);
 		newPasswordField.setOnKeyTyped(passwordEntered);
@@ -142,21 +137,9 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 
 		// Displaying the save button
 		saveButton
-			.setOnAction(e -> save(currentPasswordField.getText()));
+			.setOnAction(e -> save(client.getSender().getID(), currentPasswordField.getText()));
 		saveButton.setAlignment(Pos.BOTTOM_RIGHT);
 		getChildren().add(saveButton);
-
-		// Displaying the delete account button
-		deleteAccountButton.setAlignment(Pos.BASELINE_CENTER);
-		deleteAccountButton.setOnAction(e -> UserUtil.deleteAccount());
-		deleteAccountButton.setText("Delete Account (locally)");
-		deleteAccountButton.setPrefHeight(25);
-		deleteAccountButton.getStyleClass().clear();
-		deleteAccountButton.getStyleClass().add("danger-button");
-		final var tooltip = new Tooltip("Remote deletion is currently unsupported.");
-		tooltip.setShowDelay(Duration.millis(100));
-		deleteAccountButton.setTooltip(tooltip);
-		getChildren().add(deleteAccountButton);
 	}
 
 	/**
@@ -165,11 +148,11 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 	 * @param username the new username
 	 * @since Envoy Client v0.2-beta
 	 */
-	private void save(String oldPassword) {
+	private void save(long userID, String oldPassword) {
 
 		// The profile pic was changed
 		if (profilePicChanged) {
-			final var profilePicChangeEvent = new ProfilePicChange(currentImageBytes);
+			final var profilePicChangeEvent = new ProfilePicChange(currentImageBytes, userID);
 			eventBus.dispatch(profilePicChangeEvent);
 			client.send(profilePicChangeEvent);
 			logger.log(Level.INFO, "The user just changed his profile pic.");
@@ -178,7 +161,7 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 		// The username was changed
 		final var validContactName = Bounds.isValidContactName(newUsername);
 		if (usernameChanged && validContactName) {
-			final var nameChangeEvent = new NameChange(client.getSender().getID(), newUsername);
+			final var nameChangeEvent = new NameChange(userID, newUsername);
 			eventBus.dispatch(nameChangeEvent);
 			client.send(nameChangeEvent);
 			logger.log(Level.INFO, "The user just changed his name to " + newUsername + ".");
@@ -195,7 +178,7 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 
 		// The password was changed
 		if (validPassword) {
-			client.send(new PasswordChangeRequest(newPassword, oldPassword));
+			client.send(new PasswordChangeRequest(newPassword, oldPassword, userID));
 			logger.log(Level.INFO, "The user just tried to change his password!");
 		} else if (!(validPassword || newPassword.isBlank())) {
 			final var alert = new Alert(AlertType.ERROR);

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

@@ -7,7 +7,7 @@ import java.util.logging.*;
 
 import javafx.stage.FileChooser;
 
-import dev.kske.eventbus.core.EventBus;
+import dev.kske.eventbus.EventBus;
 
 import envoy.data.Message;
 import envoy.util.EnvoyLog;

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

@@ -2,10 +2,10 @@ package envoy.client.util;
 
 import java.util.logging.*;
 
-import javafx.scene.control.*;
+import javafx.scene.control.Alert;
 import javafx.scene.control.Alert.AlertType;
 
-import dev.kske.eventbus.core.EventBus;
+import dev.kske.eventbus.EventBus;
 
 import envoy.data.*;
 import envoy.data.User.UserStatus;
@@ -16,7 +16,7 @@ import envoy.util.EnvoyLog;
 import envoy.client.data.Context;
 import envoy.client.event.*;
 import envoy.client.helper.*;
-import envoy.client.ui.SceneInfo;
+import envoy.client.ui.SceneContext.SceneInfo;
 import envoy.client.ui.controller.ChatScene;
 
 /**
@@ -121,35 +121,4 @@ public final class UserUtil {
 			});
 		}
 	}
-
-	/**
-	 * Deletes anything pointing to this user, independent of client or server. Will do nothing if
-	 * the client is currently offline.
-	 *
-	 * @since Envoy Client v0.3-beta
-	 */
-	public static void deleteAccount() {
-
-		// Show the first wall of defense, if not disabled by the user
-		final var outerAlert = new Alert(AlertType.CONFIRMATION);
-		outerAlert.setContentText(
-			"Are you sure you want to delete your account entirely? This action can seriously not be undone.");
-		outerAlert.setTitle("Delete Account?");
-		AlertHelper.confirmAction(outerAlert, () -> {
-
-			// Show the final wall of defense in every case
-			final var lastAlert = new Alert(AlertType.WARNING,
-				"Do you REALLY want to delete your account? Last Warning. Proceed?",
-				ButtonType.CANCEL, ButtonType.OK);
-			lastAlert.setTitle("Delete Account?");
-			lastAlert.showAndWait().filter(ButtonType.OK::equals).ifPresent(b2 -> {
-
-				// Delete the account
-				// TODO: Notify server of account deletion
-				context.getLocalDB().delete();
-				logger.log(Level.INFO, "The user just deleted his account. Goodbye.");
-				ShutdownHelper.exit(true);
-			});
-		});
-	}
 }

client/src/main/java/module-info.java

@@ -16,13 +16,12 @@ module envoy.client {
 	requires javafx.fxml;
 	requires javafx.base;
 	requires javafx.graphics;
-	requires dev.kske.eventbus.core;
 
-	opens envoy.client.ui to javafx.graphics, javafx.fxml, dev.kske.eventbus.core;
+	opens envoy.client.ui to javafx.graphics, javafx.fxml, dev.kske.eventbus;
-	opens envoy.client.ui.controller to javafx.graphics, javafx.fxml, envoy.client.util, dev.kske.eventbus.core;
+	opens envoy.client.ui.controller to javafx.graphics, javafx.fxml, envoy.client.util, dev.kske.eventbus;
-	opens envoy.client.ui.chatscene to javafx.graphics, javafx.fxml, envoy.client.util, dev.kske.eventbus.core;
+	opens envoy.client.ui.chatscene to javafx.graphics, javafx.fxml, envoy.client.util, dev.kske.eventbus;
 	opens envoy.client.ui.control to javafx.graphics, javafx.fxml;
 	opens envoy.client.ui.settings to envoy.client.util;
-	opens envoy.client.net to dev.kske.eventbus.core;
+	opens envoy.client.net to dev.kske.eventbus;
-	opens envoy.client.data to dev.kske.eventbus.core;
+	opens envoy.client.data to dev.kske.eventbus;
 }

client/src/main/resources/css/base.css

@@ -70,17 +70,6 @@
 	-fx-text-fill: gray;
 }
 
-.danger-button {
-	-fx-background-color: red;
-	-fx-text-fill: white;
-	-fx-background-radius: 0.2em;
-}
-
-.danger-button:hover {
-	-fx-scale-x: 1.05;
-	-fx-scale-y: 1.05;
-}
-
 .received-message {
 	-fx-alignment: center-left;
 	-fx-background-radius: 1.3em;

client/src/main/resources/css/light.css

@@ -30,10 +30,6 @@
 	-fx-background-color: black;
 }
 
-.tooltip {
-	-fx-text-fill: black;
-}
-
 #login-input-field {
 	-fx-border-color: black;
 }

client/src/main/resources/fxml/ChatScene.fxml

@@ -24,8 +24,8 @@
 
 <GridPane maxHeight="-Infinity" maxWidth="-Infinity"
 	minHeight="400.0" minWidth="500.0"
-	prefWidth="${screen.visualBounds.width}"
 	prefHeight="${screen.visualBounds.height}"
+	prefWidth="${screen.visualBounds.width}"
 	xmlns="http://javafx.com/javafx/11.0.1"
 	xmlns:fx="http://javafx.com/fxml/1"
 	fx:controller="envoy.client.ui.controller.ChatScene">
@@ -57,7 +57,8 @@
 					<content>
 						<AnchorPane minHeight="0.0" minWidth="0.0">
 							<children>
-								<VBox prefHeight="3000.0" prefWidth="316.0">
+								<VBox prefHeight="3000.0"
+									prefWidth="316.0">
 									<children>
 										<VBox id="search-panel" maxHeight="-Infinity"
 											minHeight="-Infinity" prefHeight="80.0" prefWidth="316.0">
@@ -155,7 +156,8 @@
 						<Insets left="15.0" top="5.0" right="10.0" />
 					</HBox.margin>
 				</ImageView>
-				<Region id="transparent-background" HBox.hgrow="ALWAYS" />
+				<Region id="transparent-background"
+					HBox.hgrow="ALWAYS" />
 				<Button fx:id="settingsButton" mnemonicParsing="false"
 					onAction="#settingsButtonClicked" prefHeight="30.0"
 					prefWidth="30.0" alignment="CENTER_RIGHT">
@@ -163,7 +165,7 @@
 						<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
 					</padding>
 					<HBox.margin>
-						<Insets bottom="35.0" left="5.0" top="35.0" right="10.0" />
+						<Insets bottom="35.0" left="5.0" top="35.0" right="10.0"/>
 					</HBox.margin>
 				</Button>
 			</children>

client/src/main/resources/fxml/SettingsScene.fxml

@@ -7,16 +7,11 @@
 <?import javafx.scene.layout.HBox?>
 <?import javafx.scene.layout.VBox?>
 
-<VBox alignment="TOP_RIGHT" maxHeight="-Infinity" minHeight="400.0"
+<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">
-	minWidth="500.0" 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="389.0" prefWidth="600.0">
 			<children>
-				<ListView id="message-list" fx:id="settingsList"
+				<ListView id="message-list" fx:id="settingsList" onMouseClicked="#settingsListClicked" prefHeight="200.0" prefWidth="200.0">
-					onMouseClicked="#settingsListClicked" prefHeight="200.0"
-					prefWidth="200.0">
 					<opaqueInsets>
 						<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
 					</opaqueInsets>
@@ -27,8 +22,7 @@
 						<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
 					</padding>
 				</ListView>
-				<TitledPane fx:id="titledPane" collapsible="false"
+				<TitledPane fx:id="titledPane" collapsible="false" prefHeight="400.0" prefWidth="400.0">
-					prefHeight="400.0" prefWidth="400.0">
 					<HBox.margin>
 						<Insets bottom="10.0" left="5.0" right="10.0" top="10.0" />
 					</HBox.margin>
@@ -38,8 +32,7 @@
 				</TitledPane>
 			</children>
 		</HBox>
-		<Button defaultButton="true" mnemonicParsing="true"
+		<Button defaultButton="true" mnemonicParsing="true" onMouseClicked="#backButtonClicked" text="_Back">
-			onMouseClicked="#backButtonClicked" text="_Back">
 			<opaqueInsets>
 				<Insets />
 			</opaqueInsets>

common/pom.xml

@@ -12,11 +12,18 @@
 		<version>0.2-beta</version>
 	</parent>
 
+	<repositories>
+		<repository>
+			<id>kske-repo</id>
+			<url>https://kske.dev/maven-repo</url>
+		</repository>
+	</repositories>
+
 	<dependencies>
 		<dependency>
 			<groupId>dev.kske</groupId>
-			<artifactId>event-bus-core</artifactId>
+			<artifactId>event-bus</artifactId>
-			<version>1.0.0</version>
+			<version>0.0.4</version>
 		</dependency>
 		<dependency>
 			<groupId>org.junit.jupiter</groupId>

common/src/main/java/envoy/data/Attachment.java

@@ -1,7 +1,6 @@
 package envoy.data;
 
 import java.io.Serializable;
-import java.util.Objects;
 
 /**
  * This interface should be used for any type supposed to be a {@link Message} attachment (i.e.
@@ -64,9 +63,9 @@ public final class Attachment implements Serializable {
 	 * @since Envoy Common v0.1-beta
 	 */
 	public Attachment(byte[] data, String name, AttachmentType type) {
-		this.data	= Objects.requireNonNull(data);
+		this.data	= data;
-		this.name	= Objects.requireNonNull(name);
+		this.name	= name;
-		this.type	= Objects.requireNonNull(type);
+		this.type	= type;
 	}
 
 	/**

common/src/main/java/envoy/data/Contact.java

@@ -29,8 +29,8 @@ public abstract class Contact implements Serializable {
 	 */
 	public Contact(long id, String name, Set<? extends Contact> contacts) {
 		this.id			= id;
-		this.name		= Objects.requireNonNull(name);
+		this.name		= name;
-		this.contacts	= contacts == null ? new HashSet<>() : contacts;
+		this.contacts	= contacts;
 	}
 
 	/**

common/src/main/java/envoy/data/GroupMessage.java

@@ -38,8 +38,7 @@ public final class GroupMessage extends Message {
 		Map<Long, MessageStatus> memberStatuses) {
 		super(id, senderID, groupID, creationDate, receivedDate, readDate, text, attachment, status,
 			forwarded);
-		this.memberStatuses =
+		this.memberStatuses = memberStatuses;
-			memberStatuses == null ? new HashMap<>() : memberStatuses;
 	}
 
 	/**

common/src/main/java/envoy/data/IDGenerator.java

@@ -2,13 +2,15 @@ package envoy.data;
 
 import java.io.Serializable;
 
+import dev.kske.eventbus.IEvent;
+
 /**
  * Generates increasing IDs between two numbers.
  *
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public final class IDGenerator implements Serializable {
+public final class IDGenerator implements IEvent, Serializable {
 
 	private final long	end;
 	private long		current;

common/src/main/java/envoy/data/LoginCredentials.java

@@ -2,7 +2,6 @@ package envoy.data;
 
 import java.io.Serializable;
 import java.time.Instant;
-import java.util.Objects;
 
 /**
  * Contains a {@link User}'s login / registration information as well as the client version.
@@ -21,14 +20,15 @@ public final class LoginCredentials implements Serializable {
 	private static final long serialVersionUID = 4;
 
 	private LoginCredentials(String identifier, String password, boolean registration,
-		boolean token, boolean requestToken, String clientVersion, Instant lastSync) {
+		boolean token, boolean requestToken, String clientVersion,
-		this.identifier		= Objects.requireNonNull(identifier);
+		Instant lastSync) {
-		this.password		= Objects.requireNonNull(password);
+		this.identifier		= identifier;
+		this.password		= password;
 		this.registration	= registration;
 		this.token			= token;
 		this.requestToken	= requestToken;
-		this.clientVersion	= Objects.requireNonNull(clientVersion);
+		this.clientVersion	= clientVersion;
-		this.lastSync		= lastSync == null ? Instant.EPOCH : lastSync;
+		this.lastSync		= lastSync;
 	}
 
 	/**
@@ -75,8 +75,7 @@ public final class LoginCredentials implements Serializable {
 	 * @since Envoy Common v0.2-beta
 	 */
 	public static LoginCredentials registration(String identifier, String password,
-		boolean requestToken,
+		boolean requestToken, String clientVersion, Instant lastSync) {
-		String clientVersion, Instant lastSync) {
 		return new LoginCredentials(identifier, password, true, false, requestToken, clientVersion,
 			lastSync);
 	}

common/src/main/java/envoy/data/Message.java

@@ -2,7 +2,8 @@ package envoy.data;
 
 import java.io.Serializable;
 import java.time.Instant;
-import java.util.Objects;
+
+import dev.kske.eventbus.IEvent;
 
 /**
  * Represents a unique message with a unique, numeric ID. Further metadata includes the sender and
@@ -12,7 +13,7 @@ import java.util.Objects;
  * @author Leon Hofmeister
  * @since Envoy Common v0.2-alpha
  */
-public class Message implements Serializable {
+public class Message implements Serializable, IEvent {
 
 	/**
 	 * This enumeration defines all possible statuses a {link Message} can have.
@@ -79,9 +80,9 @@ public class Message implements Serializable {
 		this.creationDate	= creationDate;
 		this.receivedDate	= receivedDate;
 		this.readDate		= readDate;
-		this.text			= text == null ? "" : text;
+		this.text			= text;
 		this.attachment		= attachment;
-		this.status			= Objects.requireNonNull(status);
+		this.status			= status;
 		this.forwarded		= forwarded;
 	}
 

common/src/main/java/envoy/data/User.java

@@ -86,7 +86,7 @@ public final class User extends Contact {
 	 */
 	public User(long id, String name, UserStatus status, Set<Contact> contacts) {
 		super(id, name, contacts);
-		this.status = Objects.requireNonNull(status);
+		this.status = status;
 	}
 
 	@Override

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

@@ -1,33 +1,26 @@
 package envoy.event;
 
 import java.io.Serializable;
-import java.util.Objects;
+
+import dev.kske.eventbus.IEvent;
 
 /**
- * This class serves as a convenience base class for all events. It provides a generic value. For
+ * This class serves as a convenience base class for all events. It implements the {@link IEvent}
- * events without a value there also is {@link envoy.event.Event.Valueless}.
+ * interface and provides a generic value. For events without a value there also is
+ * {@link envoy.event.Event.Valueless}.
  *
  * @author Kai S. K. Engelbart
  * @param <T> the type of the Event
  * @since Envoy v0.2-alpha
  */
-public abstract class Event<T> implements Serializable {
+public abstract class Event<T> implements IEvent, Serializable {
 
 	protected final T value;
 
 	private static final long serialVersionUID = 0L;
 
 	protected Event(T value) {
-		this(value, false);
+		this.value = value;
-	}
-
-	/**
-	 * This constructor is reserved for {@link Valueless} events. No other event should contain null
-	 * values. Only use if really necessary. Using this constructor with {@code true} implies that
-	 * the user has to manually check if the value of the event is null.
-	 */
-	protected Event(T value, boolean canBeNull) {
-		this.value = canBeNull ? value : Objects.requireNonNull(value);
 	}
 
 	/**
@@ -53,7 +46,7 @@ public abstract class Event<T> implements Serializable {
 		private static final long serialVersionUID = 0L;
 
 		protected Valueless() {
-			super(null, true);
+			super(null);
 		}
 
 		@Override

common/src/main/java/envoy/event/GroupCreationResult.java

@@ -20,7 +20,7 @@ public class GroupCreationResult extends Event<Group> {
 	 * @since Envoy Common v0.2-beta
 	 */
 	public GroupCreationResult() {
-		super(null, true);
+		super(null);
 	}
 
 	/**

common/src/main/java/envoy/event/GroupMessageStatusChange.java

@@ -30,7 +30,7 @@ public final class GroupMessageStatusChange extends MessageStatusChange {
 	}
 
 	/**
-	 * @return the ID of the sender of this event
+	 * @return the memberID which the user who sends this event has
 	 * @since Envoy Common v0.1-beta
 	 */
 	public long getMemberID() { return memberID; }

common/src/main/java/envoy/event/GroupResize.java

@@ -2,8 +2,6 @@ package envoy.event;
 
 import static envoy.event.ElementOperation.*;
 
-import java.util.Objects;
-
 import envoy.data.*;
 
 /**
@@ -32,7 +30,7 @@ public final class GroupResize extends Event<User> {
 	 */
 	public GroupResize(User user, Group group, ElementOperation operation) {
 		super(user);
-		this.operation = Objects.requireNonNull(operation);
+		this.operation = operation;
 		final var contained = group.getContacts().contains(user);
 		if (contained && operation.equals(ADD))
 			throw new IllegalArgumentException(String.format("Cannot add %s to %s!", user, group));

common/src/main/java/envoy/event/IsTyping.java

@@ -8,6 +8,8 @@ package envoy.event;
  */
 public final class IsTyping extends Event<Long> {
 
+	private final long destinationID;
+
 	private static final long serialVersionUID = 1L;
 
 	/**
@@ -20,13 +22,20 @@ public final class IsTyping extends Event<Long> {
 	public static final int millisecondsActive = 3500;
 
 	/**
-	 * Creates a new {@code IsTyping}. The client will only send the contact that should receive
+	 * Creates a new {@code IsTyping} event with originator and recipient.
-	 * this event. The server will send the id of the contact who sent this event.
 	 *
-	 * @param id the ID of the recipient (client)/ originator(server)
+	 * @param sourceID      the ID of the originator
+	 * @param destinationID the ID of the contact the user wrote to
 	 * @since Envoy Common v0.2-beta
 	 */
-	public IsTyping(long id) {
+	public IsTyping(Long sourceID, long destinationID) {
-		super(id);
+		super(sourceID);
+		this.destinationID = destinationID;
 	}
+
+	/**
+	 * @return the ID of the contact in whose chat the user typed something
+	 * @since Envoy Common v0.2-beta
+	 */
+	public long getDestinationID() { return destinationID; }
 }

common/src/main/java/envoy/event/IssueProposal.java

@@ -23,7 +23,7 @@ public final class IssueProposal extends Event<String> {
 	 */
 	public IssueProposal(String title, String description, boolean isBug) {
 		super(escape(title));
-		this.description	= description == null ? "" : sanitizeDescription(description);
+		this.description	= sanitizeDescription(description);
 		bug					= isBug;
 	}
 
@@ -37,8 +37,8 @@ public final class IssueProposal extends Event<String> {
 	 */
 	public IssueProposal(String title, String description, String user, boolean isBug) {
 		super(escape(title));
-		this.description	= description == null ? ""
+		this.description	=
-			: sanitizeDescription(description) + String.format("<br>Submitted by user %s.", user);
+			sanitizeDescription(description) + String.format("<br>Submitted by user %s.", user);
 		bug					= isBug;
 	}
 

common/src/main/java/envoy/event/MessageStatusChange.java

@@ -1,7 +1,6 @@
 package envoy.event;
 
 import java.time.Instant;
-import java.util.Objects;
 
 import envoy.data.Message;
 
@@ -27,7 +26,7 @@ public class MessageStatusChange extends Event<Message.MessageStatus> {
 	public MessageStatusChange(long id, Message.MessageStatus status, Instant date) {
 		super(status);
 		this.id		= id;
-		this.date	= Objects.requireNonNull(date);
+		this.date	= date;
 	}
 
 	/**

common/src/main/java/envoy/event/PasswordChangeRequest.java

@@ -1,6 +1,6 @@
 package envoy.event;
 
-import java.util.Objects;
+import envoy.data.Contact;
 
 /**
  * @author Leon Hofmeister
@@ -8,6 +8,7 @@ import java.util.Objects;
  */
 public final class PasswordChangeRequest extends Event<String> {
 
+	private final long		id;
 	private final String	oldPassword;
 
 	private static final long serialVersionUID = 0L;
@@ -15,13 +16,21 @@ public final class PasswordChangeRequest extends Event<String> {
 	/**
 	 * @param newPassword the new password of that user
 	 * @param oldPassword the old password of that user
+	 * @param userID      the ID of the user who wants to change his password
 	 * @since Envoy Common v0.2-beta
 	 */
-	public PasswordChangeRequest(String newPassword, String oldPassword) {
+	public PasswordChangeRequest(String newPassword, String oldPassword, long userID) {
 		super(newPassword);
-		this.oldPassword = Objects.requireNonNull(oldPassword);
+		this.oldPassword	= oldPassword;
+		id					= userID;
 	}
 
+	/**
+	 * @return the ID of the {@link Contact} this event is related to
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public long getID() { return id; }
+
 	/**
 	 * @return the old password of the underlying user
 	 * @since Envoy Common v0.2-beta
@@ -30,6 +39,6 @@ public final class PasswordChangeRequest extends Event<String> {
 
 	@Override
 	public String toString() {
-		return "PasswordChangeRequest[]";
+		return "PasswordChangeRequest[id=" + id + "]";
 	}
 }

common/src/main/java/envoy/event/ProfilePicChange.java

@@ -6,13 +6,23 @@ package envoy.event;
  */
 public final class ProfilePicChange extends Event<byte[]> {
 
+	private final long id;
+
 	private static final long serialVersionUID = 0L;
 
 	/**
 	 * @param value  the byte[] of the new image
+	 * @param userID the ID of the user who changed his profile pic
 	 * @since Envoy Common v0.2-beta
 	 */
-	public ProfilePicChange(byte[] value) {
+	public ProfilePicChange(byte[] value, long userID) {
 		super(value);
+		id = userID;
 	}
+
+	/**
+	 * @return the ID of the user changing his profile pic
+	 * @since Envoy Common v0.2-beta
+	 */
+	public long getId() { return id; }
 }

common/src/main/java/envoy/event/contact/UserOperation.java

@@ -1,7 +1,5 @@
 package envoy.event.contact;
 
-import java.util.Objects;
-
 import envoy.data.User;
 import envoy.event.*;
 
@@ -26,7 +24,7 @@ public final class UserOperation extends Event<User> {
 	 */
 	public UserOperation(User contact, ElementOperation operationType) {
 		super(contact);
-		this.operationType = Objects.requireNonNull(operationType);
+		this.operationType = operationType;
 	}
 
 	/**

common/src/main/java/module-info.java

@@ -16,5 +16,5 @@ module envoy.common {
 	exports envoy.event.contact;
 
 	requires transitive java.logging;
-	requires transitive dev.kske.eventbus.core;
+	requires transitive dev.kske.eventbus;
 }

common/src/test/java/envoy/data/UserTest.java

@@ -18,10 +18,10 @@ import envoy.util.SerializationUtils;
  * @author Leon Hofmeister
  * @since Envoy Common v0.1-beta
  */
-public class UserTest {
+class UserTest {
 
 	@Test
-	public void test() throws IOException, ClassNotFoundException {
+	void test() throws IOException, ClassNotFoundException {
 		User	user2				= new User(2, "kai");
 		User	user3				= new User(3, "ai");
 		User	user4				= new User(4, "ki", Set.of(user2, user3));

doc/datamodel.uxf

@@ -0,0 +1,285 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<diagram program="umlet" version="14.3.0">
+  <zoom_level>10</zoom_level>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>50</x>
+      <y>60</y>
+      <w>210</w>
+      <h>240</h>
+    </coordinates>
+    <panel_attributes>DBUser
+--
+id: Long
+nick: String
+name: String
+chats: Set&lt;DBChat&gt;
+status: UserStatus
+created: Instant
+lastSeen: Instant
+deleted: Boolean
+avatar: DBAvatar
+passwordHash: String
+authToken: String
+authTokenExpiration: Instant
+--
++toCommon(): User</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>380</x>
+      <y>330</y>
+      <w>290</w>
+      <h>160</h>
+    </coordinates>
+    <panel_attributes>DBMessage
+--
+id: Long
+sender: DBUser
+forwarded: Boolean
+deleted: Boolean
+statuses: Map&lt;DBUser, DBMessageStatus&gt;
+text: String
+attachment: DBAttachment
+--
++toCommon(): Message</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>770</x>
+      <y>320</y>
+      <w>210</w>
+      <h>100</h>
+    </coordinates>
+    <panel_attributes>DBMessageStatus
+--
+id: Long
+status: MessageStatus
+timestamp: Instant
+--
++toCommon(): MessageStatus</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>770</x>
+      <y>440</y>
+      <w>180</w>
+      <h>120</h>
+    </coordinates>
+    <panel_attributes>DBAttachment
+--
+id: Long
+name: String
+type: AttachmentType
+url: String
+--
++toCommon(): Attachment</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>510</x>
+      <y>70</y>
+      <w>200</w>
+      <h>180</h>
+    </coordinates>
+    <panel_attributes>DBChat
+--
+id: Long
+name: String
+members: Set&lt;DBUser&gt;
+admins: Set&lt;DBUser&gt;
+messages: Set&lt;DBMessage&gt;
+avatar: DBAvatar
+allowJoining: Boolean
+allowAttachments: Boolean
+--
++toCommon(): Chat</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>250</x>
+      <y>100</y>
+      <w>280</w>
+      <h>40</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;-&gt;
+m1=0..n
+m2=0..n</panel_attributes>
+    <additional_attributes>10.0;10.0;260.0;10.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>600</x>
+      <y>240</y>
+      <w>50</w>
+      <h>110</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;
+m2=0..n</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;90.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>660</x>
+      <y>360</y>
+      <w>130</w>
+      <h>40</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;
+m2=0..n</panel_attributes>
+    <additional_attributes>10.0;10.0;110.0;10.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>660</x>
+      <y>470</y>
+      <w>130</w>
+      <h>40</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;
+m2=0..1</panel_attributes>
+    <additional_attributes>10.0;10.0;110.0;10.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>140</x>
+      <y>290</y>
+      <w>260</w>
+      <h>150</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;-
+m1=0..n</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;130.0;240.0;130.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLPackage</id>
+    <coordinates>
+      <x>10</x>
+      <y>0</y>
+      <w>1010</w>
+      <h>590</h>
+    </coordinates>
+    <panel_attributes>envoy.server.data
+--
+bg=#CCCCCC</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>90</x>
+      <y>680</y>
+      <w>170</w>
+      <h>130</h>
+    </coordinates>
+    <panel_attributes>User
+--
+id: long
+nick: String
+name: String
+status: UserStatus
+created: Instant
+deleted: boolean</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>340</x>
+      <y>680</y>
+      <w>190</w>
+      <h>100</h>
+    </coordinates>
+    <panel_attributes>UserStatus
+--
+_+ONLINE: UserStatus_
+_+AWAY: UserStatus_
+_+BUSY: UserStatus_
+_+OFFLINE: UserStatus_</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>250</x>
+      <y>730</y>
+      <w>110</w>
+      <h>30</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;-</panel_attributes>
+    <additional_attributes>90.0;10.0;10.0;10.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>340</x>
+      <y>150</y>
+      <w>100</w>
+      <h>80</h>
+    </coordinates>
+    <panel_attributes>DBAvatar
+--
+id: Long
+edited: Instant
+url: String
+layer=1</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>250</x>
+      <y>190</y>
+      <w>110</w>
+      <h>40</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;-
+m1=0..1</panel_attributes>
+    <additional_attributes>90.0;10.0;10.0;10.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>430</x>
+      <y>190</y>
+      <w>100</w>
+      <h>40</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;-
+m1=0..1</panel_attributes>
+    <additional_attributes>10.0;10.0;80.0;10.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLClass</id>
+    <coordinates>
+      <x>610</x>
+      <y>680</y>
+      <w>180</w>
+      <h>130</h>
+    </coordinates>
+    <panel_attributes>Chat
+--
+id: long
+name: String
+deceased: boolean
+members: Set&lt;User&gt;
+admins: Set&lt;User&gt;
+messages: List&lt;Message&gt;</panel_attributes>
+    <additional_attributes/>
+  </element>
+</diagram>

doc/handshake_sequence_uml.uxf

@@ -0,0 +1,501 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<diagram program="umlet" version="14.3.0">
+  <zoom_level>9</zoom_level>
+  <element>
+    <id>UMLActor</id>
+    <coordinates>
+      <x>72</x>
+      <y>540</y>
+      <w>54</w>
+      <h>99</h>
+    </coordinates>
+    <panel_attributes>Client1</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>2196</x>
+      <y>504</y>
+      <w>198</w>
+      <h>171</h>
+    </coordinates>
+    <panel_attributes>Database
+halign=center
+bg=orange
+--</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>351</x>
+      <y>513</y>
+      <w>90</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>Main</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>531</x>
+      <y>513</y>
+      <w>90</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>Startup
+bg=orange</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>702</x>
+      <y>513</y>
+      <w>90</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>Client
+bg=yellow</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>873</x>
+      <y>513</y>
+      <w>90</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>LocalDB
+bg=pink</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>1548</x>
+      <y>522</y>
+      <w>189</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>LoginCredentialsProcessor
+bg=cyan</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>1809</x>
+      <y>522</y>
+      <w>135</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>PersistenceManager
+bg=gray</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>396</x>
+      <y>729</y>
+      <w>189</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+start javaFX app</panel_attributes>
+    <additional_attributes>190.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>387</x>
+      <y>720</y>
+      <w>18</w>
+      <h>54</h>
+    </coordinates>
+    <panel_attributes/>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>387</x>
+      <y>621</y>
+      <w>27</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;110.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>567</x>
+      <y>621</y>
+      <w>27</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;110.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>738</x>
+      <y>621</y>
+      <w>27</w>
+      <h>216</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;220.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>909</x>
+      <y>621</y>
+      <w>27</w>
+      <h>153</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;150.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>567</x>
+      <y>720</y>
+      <w>18</w>
+      <h>396</h>
+    </coordinates>
+    <panel_attributes>bg=orange</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>738</x>
+      <y>819</y>
+      <w>18</w>
+      <h>558</h>
+    </coordinates>
+    <panel_attributes>bg=yellow</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>909</x>
+      <y>756</y>
+      <w>18</w>
+      <h>621</h>
+    </coordinates>
+    <panel_attributes>bg=pink</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>576</x>
+      <y>756</y>
+      <w>351</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+initialize</panel_attributes>
+    <additional_attributes>370.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>1062</x>
+      <y>513</y>
+      <w>90</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>Receiver
+bg=red</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>1098</x>
+      <y>621</y>
+      <w>27</w>
+      <h>270</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;280.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>1098</x>
+      <y>873</y>
+      <w>18</w>
+      <h>504</h>
+    </coordinates>
+    <panel_attributes>bg=red</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>576</x>
+      <y>1071</y>
+      <w>180</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+init receivers
+layer=0</panel_attributes>
+    <additional_attributes>180.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>576</x>
+      <y>828</y>
+      <w>180</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+perform handshake</panel_attributes>
+    <additional_attributes>180.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>747</x>
+      <y>873</y>
+      <w>369</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+init handhake receivers
+layer=0</panel_attributes>
+    <additional_attributes>390.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>747</x>
+      <y>1071</y>
+      <w>369</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+init permanent receivers
+layer=0</panel_attributes>
+    <additional_attributes>390.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>1638</x>
+      <y>630</y>
+      <w>27</w>
+      <h>306</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;320.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>1638</x>
+      <y>918</y>
+      <w>18</w>
+      <h>558</h>
+    </coordinates>
+    <panel_attributes>bg=cyan</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>747</x>
+      <y>918</y>
+      <w>909</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+send login credentials
+layer=0</panel_attributes>
+    <additional_attributes>990.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>1872</x>
+      <y>630</y>
+      <w>27</w>
+      <h>306</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;320.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>1872</x>
+      <y>918</y>
+      <w>18</w>
+      <h>558</h>
+    </coordinates>
+    <panel_attributes>bg=gray</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>1881</x>
+      <y>918</y>
+      <w>423</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+use queries
+layer=0</panel_attributes>
+    <additional_attributes>450.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>2286</x>
+      <y>666</y>
+      <w>27</w>
+      <h>270</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;280.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>2286</x>
+      <y>918</y>
+      <w>18</w>
+      <h>558</h>
+    </coordinates>
+    <panel_attributes>bg=orange</panel_attributes>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>1647</x>
+      <y>918</y>
+      <w>243</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=&lt;&lt;-
+aquire data
+layer=0</panel_attributes>
+    <additional_attributes>250.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>1881</x>
+      <y>954</y>
+      <w>423</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;&gt;
+send query responses
+layer=0</panel_attributes>
+    <additional_attributes>450.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>1647</x>
+      <y>954</y>
+      <w>243</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;&gt;
+send aquired data
+layer=0</panel_attributes>
+    <additional_attributes>250.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>1107</x>
+      <y>990</y>
+      <w>549</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;&gt;
+send user, chats, pending messages, etc.
+layer=0</panel_attributes>
+    <additional_attributes>590.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>918</x>
+      <y>990</y>
+      <w>198</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;&gt;
+store data
+layer=0</panel_attributes>
+    <additional_attributes>200.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>99</x>
+      <y>729</y>
+      <w>306</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;
+start app</panel_attributes>
+    <additional_attributes>10.0;20.0;320.0;20.0</additional_attributes>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>90</x>
+      <y>621</y>
+      <w>27</w>
+      <h>117</h>
+    </coordinates>
+    <panel_attributes>lt=.</panel_attributes>
+    <additional_attributes>10.0;10.0;10.0;110.0</additional_attributes>
+  </element>
+  <element>
+    <id>UMLGeneric</id>
+    <coordinates>
+      <x>90</x>
+      <y>720</y>
+      <w>18</w>
+      <h>54</h>
+    </coordinates>
+    <panel_attributes/>
+    <additional_attributes/>
+  </element>
+  <element>
+    <id>Relation</id>
+    <coordinates>
+      <x>747</x>
+      <y>1026</y>
+      <w>369</w>
+      <h>36</h>
+    </coordinates>
+    <panel_attributes>lt=-&gt;&gt;
+online
+layer=0</panel_attributes>
+    <additional_attributes>390.0;20.0;10.0;20.0</additional_attributes>
+  </element>
+</diagram>

pom.xml

@@ -28,13 +28,6 @@
 				</plugin>
 			</plugins>
 		</pluginManagement>
-		<plugins>
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-surefire-plugin</artifactId>
-				<version>3.0.0-M5</version>
-			</plugin>
-		</plugins>
 	</build>
 
 	<modules>

server/src/main/java/envoy/server/data/PersistenceManager.java

@@ -1,7 +1,7 @@
 package envoy.server.data;
 
 import java.time.Instant;
-import java.util.*;
+import java.util.List;
 import java.util.logging.Level;
 
 import javax.persistence.*;
@@ -121,9 +121,8 @@ public final class PersistenceManager {
 		transaction(() -> {
 
 			// Remove this contact from the contact list of his contacts
-			for (final var remainingContact : contact.contacts)
+			for (final var remainingContact : contact.getContacts())
 				remainingContact.getContacts().remove(contact);
-			contact.contacts.clear();
 		});
 		remove(contact);
 	}
@@ -224,9 +223,6 @@ public final class PersistenceManager {
 	 * @since Envoy Server Standalone v0.2-beta
 	 */
 	public List<Message> getPendingMessages(User user, Instant lastSync) {
-		if (user == null)
-			return new ArrayList<>();
-		lastSync = Objects.requireNonNullElse(lastSync, Instant.EPOCH);
 		return entityManager.createNamedQuery(Message.getPending).setParameter("user", user)
 			.setParameter("lastSeen", lastSync).getResultList();
 	}
@@ -240,9 +236,6 @@ public final class PersistenceManager {
 	 * @since Envoy Server Standalone v0.2-beta
 	 */
 	public List<GroupMessage> getPendingGroupMessages(User user, Instant lastSync) {
-		if (user == null)
-			return new ArrayList<>();
-		lastSync = Objects.requireNonNullElse(lastSync, Instant.EPOCH);
 		return entityManager.createNamedQuery(GroupMessage.getPendingGroupMsg)
 			.setParameter("userId", user.getID())
 			.setParameter("lastSeen", lastSync)
@@ -284,7 +277,6 @@ public final class PersistenceManager {
 	 * @since Envoy Server v0.3-beta
 	 */
 	public void addContactBidirectional(Contact contact1, Contact contact2) {
-		if (!(contact1 == null || contact2 == null)) {
 
 		// Add users to each others contact list
 		contact1.getContacts().add(contact2);
@@ -296,7 +288,6 @@ public final class PersistenceManager {
 			entityManager.merge(contact2);
 		});
 	}
-	}
 
 	/**
 	 * Removes a contact from the contact list of another contact and vice versa.
@@ -317,7 +308,6 @@ public final class PersistenceManager {
 	 * @since Envoy Server v0.3-beta
 	 */
 	public void removeContactBidirectional(Contact contact1, Contact contact2) {
-		if (!(contact1 == null || contact2 == null)) {
 
 		// Remove users from each others contact list
 		contact1.getContacts().remove(contact2);
@@ -329,7 +319,6 @@ public final class PersistenceManager {
 			entityManager.merge(contact2);
 		});
 	}
-	}
 
 	/**
 	 * @param user the User whose contacts should be retrieved
@@ -342,36 +331,15 @@ public final class PersistenceManager {
 	}
 
 	private void persist(Object obj) {
-		try {
 		transaction(() -> entityManager.persist(obj));
-		} catch (EntityExistsException e) {
-			if (transaction.isActive())
-				transaction.rollback();
-			EnvoyLog.getLogger(PersistenceManager.class).log(Level.WARNING,
-				String.format("Could not persist %s: entity exists already.", obj));
-		}
 	}
 
 	private void merge(Object obj) {
-		try {
 		transaction(() -> entityManager.merge(obj));
-		} catch (IllegalArgumentException e) {
-			if (transaction.isActive())
-				transaction.rollback();
-			EnvoyLog.getLogger(PersistenceManager.class).log(Level.WARNING,
-				String.format("Could not merge %s: entity doesn't exist.", obj));
-		}
 	}
 
 	private void remove(Object obj) {
-		try {
 		transaction(() -> entityManager.remove(obj));
-		} catch (IllegalArgumentException e) {
-			if (transaction.isActive())
-				transaction.rollback();
-			EnvoyLog.getLogger(PersistenceManager.class).log(Level.WARNING,
-				String.format("Could not remove %s: entity didn't exist (for the database).", obj));
-		}
 	}
 
 	/**

server/src/main/java/envoy/server/net/ConnectionManager.java

@@ -49,10 +49,8 @@ public final class ConnectionManager implements ISocketIdListener {
 			// Notify contacts of this users offline-going
 			final envoy.server.data.User user =
 				PersistenceManager.getInstance().getUserByID(getUserIDBySocketID(socketID));
-			if (user != null) {
 			user.setLastSeen(Instant.now());
 			UserStatusChangeProcessor.updateUserStatus(user, UserStatus.OFFLINE);
-			}
 
 			// Remove the socket
 			sockets.entrySet().removeIf(e -> e.getValue() == socketID);

server/src/main/java/envoy/server/net/ObjectMessageProcessor.java

@@ -33,6 +33,7 @@ public final class ObjectMessageProcessor implements IMessageProcessor {
 		this.processors = processors;
 	}
 
+	@SuppressWarnings("unchecked")
 	@Override
 	public void process(Message message, WriteProxy writeProxy) {
 		try (ObjectInputStream in =
@@ -44,21 +45,7 @@ public final class ObjectMessageProcessor implements IMessageProcessor {
 				return;
 			}
 
-			logger.log(Level.INFO, "Received " + obj);
+			logger.fine("Received " + obj);
-
-			refer(message.socketId, writeProxy, obj);
-		} catch (IOException | ClassNotFoundException e) {
-			logger.log(Level.WARNING,
-				"An exception occurred when reading in an object: " + e);
-		}
-	}
-
-	/**
-	 * Executes the appropriate {@link ObjectProcessor} for the given input ({@code obj}), if any is
-	 * present.
-	 */
-	@SuppressWarnings("unchecked")
-	private void refer(long socketID, WriteProxy writeProxy, Object obj) {
 
 			// Get processor and input class and process object
 			for (@SuppressWarnings("rawtypes")
@@ -67,11 +54,14 @@ public final class ObjectMessageProcessor implements IMessageProcessor {
 					.getActualTypeArguments()[0];
 				if (c.equals(obj.getClass()))
 					try {
-					p.process(c.cast(obj), socketID, new ObjectWriteProxy(writeProxy));
+						p.process(c.cast(obj), message.socketId, new ObjectWriteProxy(writeProxy));
 						break;
 					} catch (IOException e) {
 						logger.log(Level.SEVERE, "Exception during processor execution: ", e);
 					}
 			}
+		} catch (IOException | ClassNotFoundException e) {
+			e.printStackTrace();
+		}
 	}
 }

server/src/main/java/envoy/server/processors/GroupMessageProcessor.java

@@ -5,7 +5,7 @@ import static envoy.server.Startup.config;
 
 import java.time.Instant;
 import java.util.Collections;
-import java.util.logging.*;
+import java.util.logging.Logger;
 
 import javax.persistence.EntityExistsException;
 
@@ -15,7 +15,6 @@ import envoy.util.EnvoyLog;
 
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.*;
-import envoy.server.util.UserAuthenticationUtil;
 
 /**
  * @author Maximilian Käfer
@@ -30,15 +29,6 @@ public final class GroupMessageProcessor implements ObjectProcessor<GroupMessage
 
 	@Override
 	public void process(GroupMessage groupMessage, long socketID, ObjectWriteProxy writeProxy) {
-
-		// Check whether the message has the expected parameters
-		if (!UserAuthenticationUtil.isExpectedUser(groupMessage.getSenderID(), socketID)
-			|| persistenceManager.getContactByID(groupMessage.getRecipientID()) == null) {
-			logger.log(Level.INFO,
-				"Received a group message with invalid parameters");
-			return;
-		}
-
 		groupMessage.nextStatus();
 
 		// Update statuses to SENT / RECEIVED depending on online status

server/src/main/java/envoy/server/processors/GroupMessageStatusChangeProcessor.java

@@ -12,7 +12,6 @@ import envoy.util.EnvoyLog;
 
 import envoy.server.data.*;
 import envoy.server.net.*;
-import envoy.server.util.UserAuthenticationUtil;
 
 /**
  * @author Maximilian Käfer
@@ -29,17 +28,7 @@ public final class GroupMessageStatusChangeProcessor
 	@Override
 	public void process(GroupMessageStatusChange statusChange, long socketID,
 		ObjectWriteProxy writeProxy) {
-
-		// Check whether the message has the expected parameters
-		if (!UserAuthenticationUtil.isExpectedUser(statusChange.getMemberID(), socketID)) {
-			logger.log(Level.INFO,
-				"Received a group message with invalid parameters");
-			return;
-		}
-		
 		GroupMessage gmsg = (GroupMessage) persistenceManager.getMessageByID(statusChange.getID());
-		if (gmsg == null)
-			return;
 
 		// Any other status than READ is not supposed to be sent to the server
 		if (statusChange.get() != MessageStatus.READ) {

server/src/main/java/envoy/server/processors/GroupResizeProcessor.java

@@ -24,10 +24,6 @@ public final class GroupResizeProcessor implements ObjectProcessor<GroupResize>
 		final var	group	= persistenceManager.getGroupByID(groupResize.getGroupID());
 		final var	sender	= persistenceManager.getUserByID(groupResize.get().getID());
 
-		// TODO: Inform the sender that this group has already been deleted
-		if (group == null)
-			return;
-
 		// Perform the desired operation
 		switch (groupResize.getOperation()) {
 			case ADD:

server/src/main/java/envoy/server/processors/IsTypingProcessor.java

@@ -23,11 +23,10 @@ public final class IsTypingProcessor implements ObjectProcessor<IsTyping> {
 		throws IOException {
 		final var contact = persistenceManager.getContactByID(event.get());
 		if (contact instanceof User) {
-			if (connectionManager.isOnline(event.get()))
+			final var destinationID = event.getDestinationID();
-				writeProxy.write(connectionManager.getSocketID(event.get()),
+			if (connectionManager.isOnline(destinationID))
-					new IsTyping(connectionManager.getUserIDBySocketID(socketID)));
+				writeProxy.write(connectionManager.getSocketID(destinationID), event);
 		} else
-			writeProxy.writeToOnlineContacts(contact.getContacts(),
+			writeProxy.writeToOnlineContacts(contact.getContacts(), event);
-				new IsTyping(connectionManager.getUserIDBySocketID(socketID)));
 	}
 }

server/src/main/java/envoy/server/processors/LoginCredentialProcessor.java

@@ -40,7 +40,6 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 		// Cache this write proxy for user-independent notifications
 		UserStatusChangeProcessor.setWriteProxy(writeProxy);
 
-		// Check for compatible versions
 		if (!VersionUtil.verifyCompatibility(credentials.getClientVersion())) {
 			logger.info("The client has the wrong version.");
 			writeProxy.write(socketID, new HandshakeRejection(WRONG_VERSION));
@@ -71,10 +70,10 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 						writeProxy.write(socketID, new HandshakeRejection(INVALID_TOKEN));
 						return;
 					}
-				} else if (!PasswordUtil.validate(credentials.getPassword(),
+				} else
-					user.getPasswordHash())) {
 
 				// Check the password hash
+				if (!PasswordUtil.validate(credentials.getPassword(), user.getPasswordHash())) {
 					logger.info(user + " has entered the wrong password.");
 					writeProxy.write(socketID, new HandshakeRejection(WRONG_PASSWORD_OR_USER));
 					return;
@@ -102,8 +101,7 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 				writeProxy.write(socketID, new HandshakeRejection(USERNAME_TAKEN));
 				return;
 			} catch (final NoResultException e) {
-
+				// Creation of a new user
-				// Create a new user
 				user = new User();
 				user.setName(credentials.getIdentifier());
 				user.setLastSeen(Instant.now());
@@ -125,6 +123,7 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 		// Process token request
 		if (credentials.requestToken()) {
 			String token;
+
 			if (user.getAuthToken() != null && user.getAuthTokenExpiration().isAfter(Instant.now()))
 
 				// Reuse existing token and delay expiration date
@@ -141,14 +140,6 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 			writeProxy.write(socketID, new NewAuthToken(token));
 		}
 
-		// Notify the user if a contact deletion has happened since he last logged in
-		if (user.getLatestContactDeletion().isAfter(user.getLastSeen()))
-			writeProxy.write(socketID, new ContactsChangedSinceLastLogin());
-
-		// Complete the handshake
-		writeProxy.write(socketID, user.toCommon());
-
-		// Send pending (group) messages and status changes
 		final var pendingMessages =
 			PersistenceManager.getInstance().getPendingMessages(user, credentials.getLastSync());
 		pendingMessages.removeIf(GroupMessage.class::isInstance);
@@ -173,10 +164,9 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 					writeProxy.write(connectionManager.getSocketID(msg.getSender().getID()),
 						new MessageStatusChange(msgCommon));
 				}
-			} else {
+			} else
 				writeProxy.write(socketID, new MessageStatusChange(msgCommon));
 		}
-		}
 
 		final List<GroupMessage> pendingGroupMessages = PersistenceManager.getInstance()
 			.getPendingGroupMessages(user, credentials.getLastSync());
@@ -209,11 +199,10 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 					}
 
 					PersistenceManager.getInstance().updateMessage(gmsg);
-				} else {
+				} else
 
 					// Just send the message without updating if it was received in the past
 					writeProxy.write(socketID, gmsgCommon);
-				}
 			} else {
 
 				// Sending group message status changes
@@ -233,5 +222,11 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 					writeProxy.write(socketID, new MessageStatusChange(gmsgCommon));
 			}
 		}
+		// Notify the user if a contact deletion has happened since he last logged in
+		if (user.getLatestContactDeletion().isAfter(user.getLastSeen()))
+			writeProxy.write(socketID, new ContactsChangedSinceLastLogin());
+
+		// Complete the handshake
+		writeProxy.write(socketID, user.toCommon());
 	}
 }

server/src/main/java/envoy/server/processors/MessageProcessor.java

@@ -12,7 +12,6 @@ import envoy.util.EnvoyLog;
 
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.*;
-import envoy.server.util.UserAuthenticationUtil;
 
 /**
  * This {@link ObjectProcessor} handles incoming {@link Message}s.
@@ -30,15 +29,6 @@ public final class MessageProcessor implements ObjectProcessor<Message> {
 
 	@Override
 	public void process(Message message, long socketID, ObjectWriteProxy writeProxy) {
-
-		// Check whether the message has the expected parameters
-		if (!UserAuthenticationUtil.isExpectedUser(message.getSenderID(), socketID)
-			|| persistenceManager.getContactByID(message.getRecipientID()) == null) {
-			logger.log(Level.INFO,
-				"Received a message with invalid parameters");
-			return;
-		}
-
 		message.nextStatus();
 
 		// Convert to server message

server/src/main/java/envoy/server/processors/MessageStatusChangeProcessor.java

@@ -32,8 +32,6 @@ public final class MessageStatusChangeProcessor implements ObjectProcessor<Messa
 		}
 
 		final var msg = persistenceManager.getMessageByID(statusChange.getID());
-		if (msg == null)
-			return;
 		msg.read();
 		persistenceManager.updateMessage(msg);
 

server/src/main/java/envoy/server/processors/PasswordChangeRequestProcessor.java

@@ -7,7 +7,7 @@ import envoy.event.*;
 import envoy.util.EnvoyLog;
 
 import envoy.server.data.PersistenceManager;
-import envoy.server.net.*;
+import envoy.server.net.ObjectWriteProxy;
 import envoy.server.util.PasswordUtil;
 
 /**
@@ -21,8 +21,7 @@ public final class PasswordChangeRequestProcessor
 	public void process(PasswordChangeRequest event, long socketID, ObjectWriteProxy writeProxy)
 		throws IOException {
 		final var	persistenceManager		= PersistenceManager.getInstance();
-		final var	user					= persistenceManager
+		final var	user					= persistenceManager.getUserByID(event.getID());
-			.getUserByID(ConnectionManager.getInstance().getUserIDBySocketID(socketID));
 		final var	logger					=
 			EnvoyLog.getLogger(PasswordChangeRequestProcessor.class);
 		final var	correctAuthentication	=

server/src/main/java/envoy/server/processors/UserOperationProcessor.java

@@ -22,15 +22,9 @@ public final class UserOperationProcessor implements ObjectProcessor<UserOperati
 	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 
 	@Override
-	public void process(UserOperation evt, long socketID, ObjectWriteProxy writeProxy) {
+	public void process(UserOperation evt, long socketId, ObjectWriteProxy writeProxy) {
-		final long	userID		= ConnectionManager.getInstance().getUserIDBySocketID(socketID);
+		final long	userID		= ConnectionManager.getInstance().getUserIDBySocketID(socketId);
 		final long	contactID	= evt.get().getID();
-		final var	recipient	= persistenceManager.getUserByID(contactID);
-
-		// TODO: Inform the sender if the requested contact has already been deleted
-		if (recipient == null)
-			return;
-
 		final var	sender		= persistenceManager.getUserByID(userID);
 		switch (evt.getOperationType()) {
 			case ADD:
@@ -51,7 +45,7 @@ public final class UserOperationProcessor implements ObjectProcessor<UserOperati
 				sender.setLatestContactDeletion(Instant.now());
 
 				// Notify the removed contact on next startup(s) of this deletion
-				recipient.setLatestContactDeletion(Instant.now());
+				persistenceManager.getUserByID(contactID).setLatestContactDeletion(Instant.now());
 
 				// Notify the removed contact if online
 				if (connectionManager.isOnline(contactID))

server/src/main/java/envoy/server/util/UserAuthenticationUtil.java

@@ -1,24 +0,0 @@
-package envoy.server.util;
-
-import envoy.server.net.ConnectionManager;
-
-/**
- * @author Leon Hofmeister
- * @since Envoy Server v0.3-beta
- */
-public final class UserAuthenticationUtil {
-
-	private UserAuthenticationUtil() {}
-
-	/**
-	 * Checks whether a user is really who he claims to be.
-	 *
-	 * @param expectedID the expected user ID
-	 * @param socketID   the socket ID of the user making a request
-	 * @return whether this user is who he claims to be
-	 * @since Envoy Server v0.3-beta
-	 */
-	public static boolean isExpectedUser(long expectedID, long socketID) {
-		return ConnectionManager.getInstance().getUserIDBySocketID(socketID) == expectedID;
-	}
-}