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

@@ -5,11 +5,13 @@ import java.nio.channels.*;
 import java.nio.file.StandardOpenOption;
 import java.time.Instant;
 import java.util.*;
+import java.util.logging.Level;
 
+import envoy.client.event.EnvoyCloseEvent;
 import envoy.data.*;
 import envoy.event.*;
 import envoy.exception.EnvoyException;
-import envoy.util.SerializationUtils;
+import envoy.util.*;
 
 import dev.kske.eventbus.Event;
 import dev.kske.eventbus.EventBus;
@@ -42,12 +44,13 @@ public final class LocalDB implements EventListener {
 	private Instant lastSync = Instant.EPOCH;
 
 	// Persistence
-	private File		dbDir, userFile, idGeneratorFile, lastLoginFile, usersFile;
+	private File		userFile;
 	private FileLock	instanceLock;
 
+	private final File dbDir, idGeneratorFile, lastLoginFile, usersFile;
+
 	/**
-	 * Constructs an empty local database. To serialize any user-specific data to
-	 * the file system, call {@link LocalDB#save(boolean)}.
+	 * Constructs an empty local database.
 	 *
 	 * @param dbDir the directory in which to persist data
 	 * @throws IOException    if {@code dbDir} is a file (and not a directory)
@@ -59,9 +62,8 @@ public final class LocalDB implements EventListener {
 		EventBus.getInstance().registerListener(this);
 
 		// Ensure that the database directory exists
-		if (!dbDir.exists()) {
-			dbDir.mkdirs();
-		} else if (!dbDir.isDirectory()) throw new IOException(String.format("LocalDBDir '%s' is not a directory!", dbDir.getAbsolutePath()));
+		if (!dbDir.exists()) dbDir.mkdirs();
+		else if (!dbDir.isDirectory()) throw new IOException(String.format("LocalDBDir '%s' is not a directory!", dbDir.getAbsolutePath()));
 
 		// Lock the directory
 		lock();
@@ -88,12 +90,12 @@ public final class LocalDB implements EventListener {
 	 * @since Envoy Client v0.2-beta
 	 */
 	private synchronized void lock() throws EnvoyException {
-		File file = new File(dbDir, "instance.lock");
+		final var file = new File(dbDir, "instance.lock");
 		try {
-			FileChannel fc = FileChannel.open(file.toPath(), StandardOpenOption.CREATE, StandardOpenOption.WRITE);
+			final var fc = FileChannel.open(file.toPath(), StandardOpenOption.CREATE, StandardOpenOption.WRITE);
 			instanceLock = fc.tryLock();
 			if (instanceLock == null) throw new EnvoyException("Another Envoy instance is using this local database!");
-		} catch (IOException e) {
+		} catch (final IOException e) {
 			throw new EnvoyException("Could not create lock file!", e);
 		}
 	}
@@ -146,9 +148,8 @@ public final class LocalDB implements EventListener {
 		users.put(user.getName(), user);
 
 		// Synchronize user status data
-		for (Contact contact : users.values())
-			if (contact instanceof User)
-				getChat(contact.getID()).ifPresent(chat -> { ((User) chat.getRecipient()).setStatus(((User) contact).getStatus()); });
+		for (final var contact : users.values())
+			if (contact instanceof User) getChat(contact.getID()).ifPresent(chat -> { ((User) chat.getRecipient()).setStatus(contact.getStatus()); });
 
 		// Create missing chats
 		user.getContacts()
@@ -162,26 +163,31 @@ public final class LocalDB implements EventListener {
 	 * Stores all users. If the client user is specified, their chats will be stored
 	 * as well. The message id generator will also be saved if present.
 	 *
-	 * @param isOnline determines which {@code lastSync} time stamp is saved
 	 * @throws IOException if the saving process failed
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public synchronized void save(boolean isOnline) throws IOException {
+	@Event(eventType = EnvoyCloseEvent.class, priority = 1000)
+	private synchronized void save() {
+		EnvoyLog.getLogger(LocalDB.class).log(Level.INFO, "Saving local database...");
 
 		// Save users
-		SerializationUtils.write(usersFile, users);
+		try {
+			SerializationUtils.write(usersFile, users);
 
-		// Save user data and last sync time stamp
-		if (user != null) SerializationUtils.write(userFile, chats, cacheMap, isOnline ? Instant.now() : lastSync);
+			// Save user data and last sync time stamp
+			if (user != null)
+				SerializationUtils.write(userFile, chats, cacheMap, Context.getInstance().getClient().isOnline() ? Instant.now() : lastSync);
 
-		// Save last login information
-		if (authToken != null) SerializationUtils.write(lastLoginFile, user, authToken);
+			// Save last login information
+			if (authToken != null) SerializationUtils.write(lastLoginFile, user, authToken);
 
-		// Save id generator
-		if (hasIDGenerator()) SerializationUtils.write(idGeneratorFile, idGenerator);
+			// Save ID generator
+			if (hasIDGenerator()) SerializationUtils.write(idGeneratorFile, idGenerator);
+		} catch (final IOException e) {
+			EnvoyLog.getLogger(LocalDB.class).log(Level.SEVERE, "Unable to save local database: ", e);
+		}
 	}
 
-
 	@Event
 	private void onNewAuthToken(NewAuthToken evt) { authToken = evt.get(); }
 

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

@@ -2,9 +2,14 @@ package envoy.client.data;
 
 import java.io.*;
 import java.util.*;
+import java.util.logging.Level;
 import java.util.prefs.Preferences;
 
-import envoy.util.SerializationUtils;
+import envoy.client.event.EnvoyCloseEvent;
+import envoy.util.*;
+
+import dev.kske.eventbus.*;
+import dev.kske.eventbus.EventListener;
 
 /**
  * Manages all application settings, which are different objects that can be
@@ -20,7 +25,7 @@ import envoy.util.SerializationUtils;
  * @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;
@@ -42,6 +47,8 @@ public final class Settings {
 	 * @since Envoy Client v0.2-alpha
 	 */
 	private Settings() {
+		EventBus.getInstance().registerListener(this);
+
 		// Load settings from settings file
 		try {
 			items = SerializationUtils.read(settingsFile, HashMap.class);
@@ -65,10 +72,16 @@ public final class Settings {
 	 * @throws IOException if an error occurs while saving the themes
 	 * @since Envoy Client v0.2-alpha
 	 */
-	public void save() throws IOException {
+	@Event(eventType = EnvoyCloseEvent.class, priority = 900)
+	private void save() {
+		EnvoyLog.getLogger(Settings.class).log(Level.INFO, "Saving settings...");
 
 		// Save settings to settings file
-		SerializationUtils.write(settingsFile, items);
+		try {
+			SerializationUtils.write(settingsFile, items);
+		} catch (final IOException e) {
+			EnvoyLog.getLogger(Settings.class).log(Level.SEVERE, "Unable to save settings file: ", e);
+		}
 	}
 
 	private void supplementDefaults() {

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

@@ -0,0 +1,16 @@
+package envoy.client.event;
+
+import envoy.event.Event.Valueless;
+
+/**
+ * This event will be sent once Envoy is <strong>really</strong> closed.
+ * Its purpose is to forcefully stop other threads peacefully so that the VM can
+ * shutdown too.
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Client v0.2-beta
+ */
+public class EnvoyCloseEvent extends Valueless {
+
+	private static final long serialVersionUID = 1L;
+}

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

@@ -6,7 +6,7 @@ import java.util.concurrent.TimeoutException;
 import java.util.logging.*;
 
 import envoy.client.data.*;
-import envoy.client.event.SendEvent;
+import envoy.client.event.*;
 import envoy.data.*;
 import envoy.event.*;
 import envoy.event.Event;
@@ -49,9 +49,7 @@ public final class Client implements EventListener, Closeable {
 	 *
 	 * @since Envoy Client v0.2-beta
 	 */
-	public Client() {
-		eventBus.registerListener(this);
-	}
+	public Client() { eventBus.registerListener(this); }
 
 	/**
 	 * Enters the online mode by acquiring a user ID from the server. As a
@@ -236,7 +234,15 @@ public final class Client implements EventListener, Closeable {
 	}
 
 	@Override
-	public void close() throws IOException { if (online) socket.close(); }
+	@dev.kske.eventbus.Event(eventType = EnvoyCloseEvent.class, priority = 800)
+	public void close() {
+		if (online) {
+			logger.log(Level.INFO, "Closing connection...");
+			try {
+				socket.close();
+			} catch (final IOException e) {}
+		}
+	}
 
 	private void writeObject(Object obj) throws IOException {
 		checkOnline();

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

@@ -2,14 +2,11 @@ package envoy.client.net;
 
 import java.io.*;
 import java.net.SocketException;
-import java.util.HashMap;
-import java.util.Map;
+import java.util.*;
 import java.util.function.Consumer;
-import java.util.logging.Level;
-import java.util.logging.Logger;
+import java.util.logging.*;
 
-import envoy.util.EnvoyLog;
-import envoy.util.SerializationUtils;
+import envoy.util.*;
 
 /**
  * Receives objects from the server and passes them to processor objects based
@@ -90,7 +87,7 @@ public final class Receiver extends Thread {
 				}
 			} catch (final SocketException | EOFException e) {
 				// Connection probably closed by client.
-				logger.log(Level.FINER, "Exiting receiver...");
+				logger.log(Level.INFO, "Exiting receiver...");
 				return;
 			} catch (final Exception e) {
 				logger.log(Level.SEVERE, "Error on receiver thread", e);

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

@@ -11,7 +11,7 @@ import javafx.scene.input.*;
 import javafx.stage.Stage;
 
 import envoy.client.data.Settings;
-import envoy.client.event.ThemeChangeEvent;
+import envoy.client.event.*;
 import envoy.util.EnvoyLog;
 
 import dev.kske.eventbus.*;
@@ -114,7 +114,10 @@ public final class SceneContext implements EventListener {
 							// Presumably no Settings are loaded in the login scene, hence Envoy is closed
 							// directly
 							if (sceneInfo != SceneInfo.LOGIN_SCENE && settings.isHideOnClose()) stage.setIconified(true);
-							else System.exit(0);
+							else {
+								EventBus.getInstance().dispatch(new EnvoyCloseEvent());
+								System.exit(0);
+							}
 						});
 
 			// The LoginScene is the only scene not intended to be resized

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

@@ -11,6 +11,7 @@ import javafx.scene.control.Alert.AlertType;
 import javafx.stage.Stage;
 
 import envoy.client.data.*;
+import envoy.client.event.EnvoyCloseEvent;
 import envoy.client.net.Client;
 import envoy.client.ui.SceneContext.SceneInfo;
 import envoy.client.ui.controller.LoginScene;
@@ -20,6 +21,8 @@ import envoy.event.*;
 import envoy.exception.EnvoyException;
 import envoy.util.EnvoyLog;
 
+import dev.kske.eventbus.EventBus;
+
 /**
  * Handles application startup and shutdown.
  * <p>
@@ -95,7 +98,7 @@ public final class Startup extends Application {
 			if (!performHandshake(
 					LoginCredentials.loginWithToken(localDB.getUser().getName(), localDB.getAuthToken(), VERSION, localDB.getLastSync())))
 				sceneContext.load(SceneInfo.LOGIN_SCENE);
-		} else 
+		} else
 			// Load login scene
 			sceneContext.load(SceneInfo.LOGIN_SCENE);
 	}
@@ -213,7 +216,7 @@ public final class Startup extends Application {
 				if (Settings.getInstance().isHideOnClose()) {
 					stage.setIconified(true);
 					e.consume();
-				}
+				} else EventBus.getInstance().dispatch(new EnvoyCloseEvent());
 			});
 
 			// Initialize status tray icon
@@ -224,25 +227,4 @@ public final class Startup extends Application {
 			});
 		}
 	}
-
-	/**
-	 * Closes the client connection and saves the local database and settings.
-	 *
-	 * @since Envoy Client v0.1-beta
-	 */
-	@Override
-	public void stop() {
-		try {
-			logger.log(Level.INFO, "Saving local database and settings...");
-			localDB.save(client.isOnline());
-			Settings.getInstance().save();
-
-			if (client.isOnline()) logger.log(Level.INFO, "Closing connection...");
-			client.close();
-
-			logger.log(Level.INFO, "Envoy was terminated by its user");
-		} catch (final Exception e) {
-			logger.log(Level.SEVERE, "Unable to save local files: ", e);
-		}
-	}
 }