Merge pull request #38 from informatik-ag-ngl/f/server_config

Added config for the server and improved config mechanism.
Additionally:
- fixed small bug in both EnvoyLog and envoy.server.Startup
- fixed bug not exiting receiver thread when the server does not send anymore
- added access authorization for issues
- added option to disable attachments and groups on both client and server
- "finalized" every class that allows doing so

client/src/main/java/envoy/client/Main.java

@@ -17,7 +17,7 @@ import envoy.client.ui.Startup;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
  */
-public class Main {
+public final class Main {
 
 	private static final boolean debug = false;
 

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

@@ -3,10 +3,8 @@ package envoy.client.data;
 import static java.util.function.Function.identity;
 
 import java.io.File;
-import java.util.logging.Level;
 
 import envoy.data.Config;
-import envoy.data.ConfigItem;
 
 /**
  * Implements a configuration specific to the Envoy Client with default values
@@ -19,7 +17,7 @@ import envoy.data.ConfigItem;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
  */
-public class ClientConfig extends Config {
+public final class ClientConfig extends Config {
 
 	private static ClientConfig config;
 
@@ -33,15 +31,13 @@ public class ClientConfig extends Config {
 	}
 
 	private ClientConfig() {
-		items.put("server", new ConfigItem<>("server", "s", identity(), null, true));
+		super(".envoy");
-		items.put("port", new ConfigItem<>("port", "p", Integer::parseInt, null, true));
+		put("server", "s", identity());
-		items.put("localDB", new ConfigItem<>("localDB", "db", File::new, new File("localDB"), true));
+		put("port", "p", Integer::parseInt);
-		items.put("ignoreLocalDB", new ConfigItem<>("ignoreLocalDB", "nodb", Boolean::parseBoolean, false, false));
+		put("localDB", "db", File::new);
-		items.put("homeDirectory", new ConfigItem<>("homeDirectory", "h", File::new, new File(System.getProperty("user.home"), ".envoy"), true));
+		put("ignoreLocalDB", "nodb", Boolean::parseBoolean);
-		items.put("fileLevelBarrier", new ConfigItem<>("fileLevelBarrier", "fb", Level::parse, Level.OFF, true));
+		put("user", "u", identity());
-		items.put("consoleLevelBarrier", new ConfigItem<>("consoleLevelBarrier", "cb", Level::parse, Level.OFF, true));
+		put("password", "pw", identity());
-		items.put("user", new ConfigItem<>("user", "u", identity()));
-		items.put("password", new ConfigItem<>("password", "pw", identity()));
 	}
 
 	/**
@@ -68,24 +64,6 @@ public class ClientConfig extends Config {
 	 */
 	public Boolean isIgnoreLocalDB() { return (Boolean) items.get("ignoreLocalDB").get(); }
 
-	/**
-	 * @return the directory in which all local files are saves
-	 * @since Envoy Client v0.2-alpha
-	 */
-	public File getHomeDirectory() { return (File) items.get("homeDirectory").get(); }
-
-	/**
-	 * @return the minimal {@link Level} to log inside the log file
-	 * @since Envoy Client v0.2-alpha
-	 */
-	public Level getFileLevelBarrier() { return (Level) items.get("fileLevelBarrier").get(); }
-
-	/**
-	 * @return the minimal {@link Level} to log inside the console
-	 * @since Envoy Client v0.2-alpha
-	 */
-	public Level getConsoleLevelBarrier() { return (Level) items.get("consoleLevelBarrier").get(); }
-
 	/**
 	 * @return the user name
 	 * @since Envoy Client v0.3-alpha

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

@@ -21,7 +21,7 @@ import envoy.event.GroupMessageStatusChange;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-beta
  */
-public class GroupChat extends Chat {
+public final class GroupChat extends Chat {
 
 	private final User sender;
 
@@ -41,13 +41,10 @@ public class GroupChat extends Chat {
 	public void read(WriteProxy writeProxy) throws IOException {
 		for (int i = messages.size() - 1; i >= 0; --i) {
 			final GroupMessage gmsg = (GroupMessage) messages.get(i);
-			if (gmsg.getSenderID() != sender.getID()) {
+			if (gmsg.getSenderID() != sender.getID()) if (gmsg.getMemberStatuses().get(sender.getID()) == MessageStatus.READ) break;
-				if (gmsg.getMemberStatuses().get(sender.getID()) == MessageStatus.READ) break;
+			else {
-				else {
+				gmsg.getMemberStatuses().replace(sender.getID(), MessageStatus.READ);
-					gmsg.getMemberStatuses().replace(sender.getID(), MessageStatus.READ);
+				writeProxy.writeMessageStatusChange(new GroupMessageStatusChange(gmsg.getID(), MessageStatus.READ, Instant.now(), sender.getID()));
-					writeProxy
-						.writeMessageStatusChange(new GroupMessageStatusChange(gmsg.getID(), MessageStatus.READ, Instant.now(), sender.getID()));
-				}
 			}
 		}
 		unreadAmount = 0;

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

@@ -22,7 +22,7 @@ import envoy.util.SerializationUtils;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.2-alpha
  */
-public class Settings {
+public final class Settings {
 
 	// Actual settings accessible by the rest of the application
 	private Map<String, SettingsItem<?>> items;
@@ -139,7 +139,9 @@ public class Settings {
 	 *                         before
 	 * @since Envoy Client v0.2-beta
 	 */
-	public void setDownloadSavedWithoutAsking(boolean autosaveDownload) { ((SettingsItem<Boolean>) items.get("autoSaveDownloads")).set(autosaveDownload); }
+	public void setDownloadSavedWithoutAsking(boolean autosaveDownload) {
+		((SettingsItem<Boolean>) items.get("autoSaveDownloads")).set(autosaveDownload);
+	}
 
 	/**
 	 * @return the path where downloads should be saved

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

@@ -17,7 +17,7 @@ import javax.swing.JComponent;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class SettingsItem<T> implements Serializable {
+public final class SettingsItem<T> implements Serializable {
 
 	private T		value;
 	private String	userFriendlyName, description;

client/src/main/java/envoy/client/data/commands/SystemCommand.java

@@ -24,7 +24,7 @@ import java.util.function.Supplier;
  * @author Leon Hofmeister
  * @since Envoy Client v0.2-beta
  */
-public class SystemCommand implements OnCall {
+public final class SystemCommand implements OnCall {
 
 	protected int relevance;
 

client/src/main/java/envoy/client/data/commands/SystemCommandBuilder.java

@@ -14,7 +14,7 @@ import java.util.function.Consumer;
  * @author Leon Hofmeister
  * @since Envoy Client v0.2-beta
  */
-public class SystemCommandBuilder {
+public final class SystemCommandBuilder {
 
 	private int						numberOfArguments;
 	private Consumer<List<String>>	action;

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

@@ -11,7 +11,7 @@ import envoy.event.Event;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.2-alpha
  */
-public class MessageCreationEvent extends Event<Message> {
+public final class MessageCreationEvent extends Event<Message> {
 
 	private static final long serialVersionUID = 0L;
 

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

@@ -11,7 +11,7 @@ import envoy.event.Event;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.2-alpha
  */
-public class MessageModificationEvent extends Event<Message> {
+public final class MessageModificationEvent extends Event<Message> {
 
 	private static final long serialVersionUID = 0L;
 

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

@@ -10,7 +10,7 @@ import envoy.event.Event;
  * @author: Maximilian K&aumlfer
  * @since Envoy Client v0.3-alpha
  */
-public class SendEvent extends Event<Event<?>> {
+public final class SendEvent extends Event<Event<?>> {
 
 	private static final long serialVersionUID = 0L;
 

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

@@ -10,7 +10,7 @@ import envoy.event.Event;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.2-alpha
  */
-public class ThemeChangeEvent extends Event<String> {
+public final class ThemeChangeEvent extends Event<String> {
 
 	private static final long serialVersionUID = 0L;
 

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

@@ -29,7 +29,7 @@ import envoy.util.SerializationUtils;
  * @author Leon Hofmeister
  * @since Envoy Client v0.1-alpha
  */
-public class Client implements Closeable {
+public final class Client implements Closeable {
 
 	// Connection handling
 	private Socket		socket;
@@ -164,6 +164,13 @@ public class Client implements Closeable {
 		// Process ProfilePicChanges
 		receiver.registerProcessor(ProfilePicChange.class, eventBus::dispatch);
 
+		// Process requests to not send any more attachments as they will not be shown to
+		// other users
+		receiver.registerProcessor(NoAttachments.class, eventBus::dispatch);
+
+		// Process group creation results - they might have been disabled on the server
+		receiver.registerProcessor(GroupCreationResult.class, eventBus::dispatch);
+
 		// Send event
 		eventBus.register(SendEvent.class, evt -> {
 			try {

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

@@ -16,7 +16,7 @@ import envoy.util.EnvoyLog;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-beta
  */
-public class GroupMessageStatusChangeProcessor implements Consumer<GroupMessageStatusChange> {
+public final class GroupMessageStatusChangeProcessor implements Consumer<GroupMessageStatusChange> {
 
 	private static final Logger logger = EnvoyLog.getLogger(GroupMessageStatusChangeProcessor.class);
 

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

@@ -16,7 +16,7 @@ import envoy.util.EnvoyLog;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class MessageStatusChangeProcessor implements Consumer<MessageStatusChange> {
+public final class MessageStatusChangeProcessor implements Consumer<MessageStatusChange> {
 
 	private static final Logger logger = EnvoyLog.getLogger(MessageStatusChangeProcessor.class);
 

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

@@ -17,7 +17,7 @@ import envoy.util.EnvoyLog;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-beta
  */
-public class ReceivedGroupMessageProcessor implements Consumer<GroupMessage> {
+public final class ReceivedGroupMessageProcessor implements Consumer<GroupMessage> {
 
 	private static final Logger logger = EnvoyLog.getLogger(ReceivedGroupMessageProcessor.class);
 

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

@@ -15,7 +15,7 @@ import envoy.event.EventBus;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class ReceivedMessageProcessor implements Consumer<Message> {
+public final class ReceivedMessageProcessor implements Consumer<Message> {
 
 	@Override
 	public void accept(Message message) {

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

@@ -22,7 +22,9 @@ import envoy.util.SerializationUtils;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class Receiver extends Thread {
+public final class Receiver extends Thread {
+
+	private boolean isAlive = true;
 
 	private final InputStream					in;
 	private final Map<Class<?>, Consumer<?>>	processors	= new HashMap<>();
@@ -49,7 +51,7 @@ public class Receiver extends Thread {
 	@Override
 	public void run() {
 
-		while (true) {
+		while (isAlive)
 			try {
 				// Read object length
 				final byte[] lenBytes = new byte[4];
@@ -64,6 +66,12 @@ public class Receiver extends Thread {
 
 				// Catch LV encoding errors
 				if (len != bytesRead) {
+					// Server has stopped sending, i.e. because he went offline
+					if (bytesRead == -1) {
+						isAlive = false;
+						logger.log(Level.INFO, "Lost connection to the server. Exiting receiver...");
+						continue;
+					}
 					logger.log(Level.WARNING,
 							String.format("LV encoding violated: expected %d bytes, received %d bytes. Discarding object...", len, bytesRead));
 					continue;
@@ -87,7 +95,6 @@ public class Receiver extends Thread {
 			} catch (final Exception e) {
 				logger.log(Level.SEVERE, "Error on receiver thread", e);
 			}
-		}
 	}
 
 	/**

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

@@ -22,7 +22,7 @@ import envoy.util.EnvoyLog;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class WriteProxy {
+public final class WriteProxy {
 
 	private final Client	client;
 	private final LocalDB	localDB;
@@ -68,9 +68,7 @@ public class WriteProxy {
 	 *
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public void flushCache() {
+	public void flushCache() { localDB.getCacheMap().getMap().values().forEach(Cache::relay); }
-		localDB.getCacheMap().getMap().values().forEach(Cache::relay);
-	}
 
 	/**
 	 * Delivers a message to the server if online. Otherwise the message is cached

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

@@ -22,7 +22,7 @@ import javafx.scene.layout.GridPane;
  * @author Leon Hofmeister
  * @since Envoy Client v0.1-beta
  */
-public class ClearableTextField extends GridPane {
+public final class ClearableTextField extends GridPane {
 
 	private final TextField textField;
 
@@ -88,82 +88,82 @@ public class ClearableTextField extends GridPane {
 	 * @see javafx.scene.control.TextInputControl#promptTextProperty()
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final StringProperty promptTextProperty() { return textField.promptTextProperty(); }
+	public StringProperty promptTextProperty() { return textField.promptTextProperty(); }
 
 	/**
 	 * @return the current prompt text
 	 * @see javafx.scene.control.TextInputControl#getPromptText()
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final String getPromptText() { return textField.getPromptText(); }
+	public String getPromptText() { return textField.getPromptText(); }
 
 	/**
 	 * @param value the prompt text to display
 	 * @see javafx.scene.control.TextInputControl#setPromptText(java.lang.String)
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final void setPromptText(String value) { textField.setPromptText(value); }
+	public void setPromptText(String value) { textField.setPromptText(value); }
 
 	/**
 	 * @return the current property of the tooltip
 	 * @see javafx.scene.control.Control#tooltipProperty()
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final ObjectProperty<Tooltip> tooltipProperty() { return textField.tooltipProperty(); }
+	public ObjectProperty<Tooltip> tooltipProperty() { return textField.tooltipProperty(); }
 
 	/**
 	 * @param value the new tooltip
 	 * @see javafx.scene.control.Control#setTooltip(javafx.scene.control.Tooltip)
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final void setTooltip(Tooltip value) { textField.setTooltip(value); }
+	public void setTooltip(Tooltip value) { textField.setTooltip(value); }
 
 	/**
 	 * @return the current tooltip
 	 * @see javafx.scene.control.Control#getTooltip()
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final Tooltip getTooltip() { return textField.getTooltip(); }
+	public Tooltip getTooltip() { return textField.getTooltip(); }
 
 	/**
 	 * @return the current property of the context menu
 	 * @see javafx.scene.control.Control#contextMenuProperty()
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final ObjectProperty<ContextMenu> contextMenuProperty() { return textField.contextMenuProperty(); }
+	public ObjectProperty<ContextMenu> contextMenuProperty() { return textField.contextMenuProperty(); }
 
 	/**
 	 * @param value the new context menu
 	 * @see javafx.scene.control.Control#setContextMenu(javafx.scene.control.ContextMenu)
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final void setContextMenu(ContextMenu value) { textField.setContextMenu(value); }
+	public void setContextMenu(ContextMenu value) { textField.setContextMenu(value); }
 
 	/**
 	 * @return the current context menu
 	 * @see javafx.scene.control.Control#getContextMenu()
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final ContextMenu getContextMenu() { return textField.getContextMenu(); }
+	public ContextMenu getContextMenu() { return textField.getContextMenu(); }
 
 	/**
 	 * @param value whether this ClearableTextField should be editable
 	 * @see javafx.scene.control.TextInputControl#setEditable(boolean)
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final void setEditable(boolean value) { textField.setEditable(value); }
+	public void setEditable(boolean value) { textField.setEditable(value); }
 
 	/**
 	 * @return the current property whether this ClearableTextField is editable
 	 * @see javafx.scene.control.TextInputControl#editableProperty()
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final BooleanProperty editableProperty() { return textField.editableProperty(); }
+	public BooleanProperty editableProperty() { return textField.editableProperty(); }
 
 	/**
 	 * @return whether this {@code ClearableTextField} is editable
 	 * @see javafx.scene.control.TextInputControl#isEditable()
 	 * @since Envoy Client v0.1-beta
 	 */
-	public final boolean isEditable() { return textField.isEditable(); }
+	public boolean isEditable() { return textField.isEditable(); }
 }

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

@@ -24,7 +24,7 @@ import envoy.util.EnvoyLog;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
  */
-public class IconUtil {
+public final class IconUtil {
 
 	private IconUtil() {}
 
@@ -160,7 +160,7 @@ public class IconUtil {
 		BufferedImage image = null;
 		try {
 			image = ImageIO.read(IconUtil.class.getResource(path));
-		} catch (IOException e) {
+		} catch (final IOException e) {
 			EnvoyLog.getLogger(IconUtil.class).log(Level.WARNING, String.format("Could not load image at path %s: ", path), e);
 		}
 		return image;

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

@@ -2,7 +2,6 @@ package envoy.client.ui;
 
 import java.io.File;
 import java.io.IOException;
-import java.util.Properties;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -19,7 +18,6 @@ import envoy.data.GroupMessage;
 import envoy.data.Message;
 import envoy.event.GroupMessageStatusChange;
 import envoy.event.MessageStatusChange;
-import envoy.exception.EnvoyException;
 import envoy.util.EnvoyLog;
 
 /**
@@ -57,30 +55,13 @@ public final class Startup extends Application {
 	@Override
 	public void start(Stage stage) throws Exception {
 		try {
-			// Load the configuration from client.properties first
+			config.loadAll(Startup.class, "client.properties", getParameters().getRaw().toArray(new String[0]));
-			final Properties properties = new Properties();
+			EnvoyLog.initialize(config);
-			properties.load(Startup.class.getClassLoader().getResourceAsStream("client.properties"));
+		} catch (final IllegalStateException e) {
-			config.load(properties);
-
-			// Override configuration values with command line arguments
-			final String[] args = getParameters().getRaw().toArray(new String[0]);
-			if (args.length > 0) config.load(args);
-
-			// Check if all mandatory configuration values have been initialized
-			if (!config.isInitialized()) throw new EnvoyException("Configuration is not fully initialized");
-		} catch (final Exception e) {
 			new Alert(AlertType.ERROR, "Error loading configuration values:\n" + e);
 			logger.log(Level.SEVERE, "Error loading configuration values: ", e);
-			e.printStackTrace();
 			System.exit(1);
 		}
-
-		// Setup logger for the envoy package
-		EnvoyLog.initialize(config);
-		EnvoyLog.attach("envoy");
-		EnvoyLog.setFileLevelBarrier(config.getFileLevelBarrier());
-		EnvoyLog.setConsoleLevelBarrier(config.getConsoleLevelBarrier());
-
 		logger.log(Level.INFO, "Envoy starting...");
 
 		// Initialize the local database

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

@@ -18,7 +18,7 @@ import envoy.event.EventBus;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.2-alpha
  */
-public class StatusTrayIcon {
+public final class StatusTrayIcon {
 
 	/**
 	 * The {@link TrayIcon} provided by the System Tray API for controlling the
@@ -85,7 +85,7 @@ public class StatusTrayIcon {
 	public void show() {
 		try {
 			SystemTray.getSystemTray().add(trayIcon);
-		} catch (AWTException e) {}
+		} catch (final AWTException e) {}
 	}
 
 	/**

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

@@ -87,6 +87,12 @@ public final class ChatScene implements Restorable {
 	@FXML
 	private Button rotateButton;
 
+	@FXML
+	private Button messageSearchButton;
+
+	@FXML
+	private Button newGroupButton;
+
 	@FXML
 	private TextArea messageTextArea;
 
@@ -108,9 +114,6 @@ public final class ChatScene implements Restorable {
 	@FXML
 	private Label topBarStatusLabel;
 
-	@FXML
-	private Button messageSearchButton;
-
 	@FXML
 	private ImageView clientProfilePic;
 
@@ -129,7 +132,7 @@ public final class ChatScene implements Restorable {
 	private AudioRecorder	recorder;
 	private boolean			recording;
 	private Attachment		pendingAttachment;
-	private boolean			postingPermanentlyDisabled;
+	private boolean postingPermanentlyDisabled;
 
 	private final SystemCommandsMap messageTextAreaCommands = new SystemCommandsMap();
 
@@ -237,6 +240,21 @@ public final class ChatScene implements Restorable {
 					break;
 			}
 		});
+
+		// Disable attachment button if server says attachments will be filtered out
+		eventBus.register(NoAttachments.class, e -> {
+			Platform.runLater(() -> {
+				attachmentButton.setDisable(true);
+				voiceButton.setDisable(true);
+				final var alert = new Alert(AlertType.ERROR);
+				alert.setTitle("No attachments possible");
+				alert.setHeaderText("Your current server does not support attachments.");
+				alert.setContentText("If this is unplanned, please contact your server administrator.");
+				alert.showAndWait();
+			});
+		});
+
+		eventBus.register(GroupCreationResult.class, e -> Platform.runLater(() -> { newGroupButton.setDisable(!e.get()); }));
 	}
 
 	/**

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

@@ -6,10 +6,8 @@ import java.util.logging.Logger;
 
 import javafx.application.Platform;
 import javafx.fxml.FXML;
-import javafx.scene.control.Alert;
+import javafx.scene.control.*;
 import javafx.scene.control.Alert.AlertType;
-import javafx.scene.control.ButtonType;
-import javafx.scene.control.ListView;
 
 import envoy.client.data.LocalDB;
 import envoy.client.event.SendEvent;
@@ -20,6 +18,7 @@ import envoy.client.ui.listcell.ListCellFactory;
 import envoy.data.User;
 import envoy.event.ElementOperation;
 import envoy.event.EventBus;
+import envoy.event.GroupCreationResult;
 import envoy.event.contact.ContactOperation;
 import envoy.event.contact.UserSearchRequest;
 import envoy.event.contact.UserSearchResult;
@@ -42,7 +41,7 @@ import envoy.util.EnvoyLog;
  * @author Leon Hofmeister
  * @since Envoy Client v0.1-beta
  */
-public class ContactSearchScene {
+public final class ContactSearchScene {
 
 	@FXML
 	private ClearableTextField searchBar;
@@ -50,6 +49,9 @@ public class ContactSearchScene {
 	@FXML
 	private ListView<User> userList;
 
+	@FXML
+	private Button newGroupButton;
+
 	private SceneContext sceneContext;
 
 	private LocalDB localDB;
@@ -86,6 +88,7 @@ public class ContactSearchScene {
 		eventBus.register(UserSearchResult.class,
 				response -> Platform.runLater(() -> { userList.getItems().clear(); userList.getItems().addAll(response.get()); }));
 		eventBus.register(ContactOperation.class, handler);
+		eventBus.register(GroupCreationResult.class, e -> Platform.runLater(() -> { newGroupButton.setDisable(!e.get()); }));
 	}
 
 	/**

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

@@ -21,6 +21,7 @@ import envoy.data.Group;
 import envoy.data.User;
 import envoy.event.EventBus;
 import envoy.event.GroupCreation;
+import envoy.event.GroupCreationResult;
 import envoy.util.Bounds;
 
 /**
@@ -39,7 +40,7 @@ import envoy.util.Bounds;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-beta
  */
-public class GroupCreationScene {
+public final class GroupCreationScene {
 
 	@FXML
 	private Button createButton;
@@ -54,6 +55,8 @@ public class GroupCreationScene {
 
 	private LocalDB localDB;
 
+	private String groupName;
+
 	private static final EventBus eventBus = EventBus.getInstance();
 
 	@FXML
@@ -61,6 +64,18 @@ public class GroupCreationScene {
 		userList.setCellFactory(new ListCellFactory<>(ContactControl::new));
 		userList.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
 		groupNameField.setClearButtonListener(e -> { groupNameField.getTextField().clear(); createButton.setDisable(true); });
+		eventBus.register(GroupCreationResult.class, e -> Platform.runLater(() -> {
+			if (e.get()) new Alert(AlertType.INFORMATION, String.format("Group '%s' successfully created.", groupName)).showAndWait();
+			else {
+				createButton.setDisable(true);
+				final var alert = new Alert(AlertType.ERROR);
+				alert.setTitle("Groups are not allowed");
+				alert.setHeaderText("Cannot create group as your current server disabled this feature");
+				alert.setContentText("If this is unplanned, please contact your server administrator.");
+				alert.showAndWait();
+				sceneContext.pop();
+			}
+		}));
 	}
 
 	/**
@@ -119,10 +134,7 @@ public class GroupCreationScene {
 			alert.setTitle("Create Group?");
 			alert.setHeaderText("Proceed?");
 			alert.showAndWait().filter(btn -> btn == ButtonType.OK).ifPresent(btn -> createGroup(name));
-		} else {
+		} else createGroup(name);
-			new Alert(AlertType.INFORMATION, String.format("Group '%s' successfully created.", name)).showAndWait();
-			createGroup(name);
-		}
 	}
 
 	/**
@@ -133,9 +145,9 @@ public class GroupCreationScene {
 	 * @since Envoy Client v0.1-beta
 	 */
 	private void createGroup(String name) {
+		groupName = name;
 		eventBus.dispatch(new SendEvent(
 				new GroupCreation(name, userList.getSelectionModel().getSelectedItems().stream().map(User::getID).collect(Collectors.toSet()))));
-		sceneContext.pop();
 	}
 
 	/**

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

@@ -18,7 +18,7 @@ import envoy.client.ui.settings.*;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
  */
-public class SettingsScene {
+public final class SettingsScene {
 
 	@FXML
 	private ListView<SettingsPane> settingsList;

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

@@ -23,7 +23,7 @@ import envoy.data.Group;
  * @author Leon Hofmeister
  * @since Envoy Client v0.1-beta
  */
-public class ChatControl extends HBox {
+public final class ChatControl extends HBox {
 
 	/**
 	 * @param chat the chat to display
@@ -36,7 +36,7 @@ public class ChatControl extends HBox {
 		ImageView contactProfilePic;
 		if (chat.getRecipient() instanceof Group) contactProfilePic = new ImageView(IconUtil.loadIconThemeSensitive("group_icon", 32));
 		else contactProfilePic = new ImageView(IconUtil.loadIconThemeSensitive("user_icon", 32));
-		Rectangle	clip				= new Rectangle();
+		final var clip = new Rectangle();
 		clip.setWidth(32);
 		clip.setHeight(32);
 		clip.setArcHeight(32);
@@ -44,7 +44,7 @@ public class ChatControl extends HBox {
 		contactProfilePic.setClip(clip);
 		getChildren().add(contactProfilePic);
 		// spacing
-		Region leftSpacing = new Region();
+		final var leftSpacing = new Region();
 		leftSpacing.setPrefSize(8, 0);
 		leftSpacing.setMinSize(8, 0);
 		leftSpacing.setMaxSize(8, 0);

client/src/main/java/envoy/client/ui/listcell/ContactControl.java

@@ -18,7 +18,7 @@ import envoy.data.User;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.2-beta
  */
-public class ContactControl extends VBox {
+public final class ContactControl extends VBox {
 
 	/**
 	 * @param contact the contact to display
@@ -36,9 +36,7 @@ public class ContactControl extends VBox {
 			final var	statusLabel	= new Label(status);
 			statusLabel.getStyleClass().add(status.toLowerCase());
 			getChildren().add(statusLabel);
-		} else {
+		} else getChildren().add(new Label(contact.getContacts().size() + " members"));
-			getChildren().add(new Label(contact.getContacts().size() + " members"));
-		}
 		getStyleClass().add("listElement");
 	}
 }

client/src/main/java/envoy/client/ui/listcell/MessageControl.java

@@ -24,7 +24,6 @@ import envoy.client.data.Settings;
 import envoy.client.ui.AudioControl;
 import envoy.client.ui.IconUtil;
 import envoy.client.ui.SceneContext;
-
 import envoy.data.GroupMessage;
 import envoy.data.Message;
 import envoy.data.Message.MessageStatus;
@@ -42,7 +41,7 @@ import envoy.util.EnvoyLog;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-beta
  */
-public class MessageControl extends Label {
+public final class MessageControl extends Label {
 
 	private boolean ownMessage;
 

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

@@ -21,7 +21,7 @@ import envoy.event.IssueProposal;
  * @author Leon Hofmeister
  * @since Envoy Client v0.2-beta
  */
-public class BugReportPane extends OnlyIfOnlineSettingsPane {
+public final class BugReportPane extends OnlyIfOnlineSettingsPane {
 
 	private final Label		titleLabel				= new Label("Suggest a title for the bug:");
 	private final TextField	titleTextField			= new TextField();

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

@@ -17,7 +17,7 @@ import envoy.client.ui.SceneContext;
  * @author Leon Hofmeister
  * @since Envoy Client v0.2-beta
  */
-public class DownloadSettingsPane extends SettingsPane {
+public final class DownloadSettingsPane extends SettingsPane {
 
 	/**
 	 * Constructs a new {@code DownloadSettingsPane}.

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

@@ -16,7 +16,7 @@ import envoy.event.EventBus;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
  */
-public class GeneralSettingsPane extends SettingsPane {
+public final class GeneralSettingsPane extends SettingsPane {
 
 	/**
 	 * @since Envoy Client v0.1-beta

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

@@ -35,7 +35,7 @@ import envoy.util.EnvoyLog;
  * @author Leon Hofmeister
  * @since Envoy Client v0.2-beta
  */
-public class UserSettingsPane extends OnlyIfOnlineSettingsPane {
+public final class UserSettingsPane extends OnlyIfOnlineSettingsPane {
 
 	private boolean	profilePicChanged, usernameChanged, validPassword;
 	private byte[]	currentImageBytes;

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

@@ -10,7 +10,7 @@ package envoy.client.util;
  * @author Leon Hofmeister
  * @since Envoy Client v0.2-beta
  */
-public class IssueUtil {
+public final class IssueUtil {
 
 	/**
 	 *

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

@@ -15,7 +15,7 @@ import javafx.scene.Node;
  * @author Leon Hofmeister
  * @since Envoy Client v0.2-beta
  */
-public class ReflectionUtil {
+public final class ReflectionUtil {
 
 	private ReflectionUtil() {}
 

client/src/main/resources/client.properties

@@ -2,3 +2,5 @@ server=localhost
 port=8080
 localDB=localDB
 consoleLevelBarrier=FINER
+fileLevelBarrier=OFF
+ignoreLocalDB=false

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

@@ -62,7 +62,7 @@
                               <Insets />
                            </HBox.margin>
       						</Button>
-                        <Button mnemonicParsing="false" prefWidth="100.0" text="New Group">
+                        <Button fx:id="newGroupButton" mnemonicParsing="false" prefWidth="100.0" text="New Group">
                            <HBox.margin>
                               <Insets />
                            </HBox.margin>

client/src/main/resources/fxml/ContactSearchScene.fxml

@@ -34,7 +34,7 @@
 							wrapText="true" />
 					</tooltip>
 				</ClearableTextField>
-				<Button mnemonicParsing="false"
+				<Button fx:id="newGroupButton" mnemonicParsing="false"
 					onAction="#newGroupButtonClicked" prefHeight="26.0"
 					prefWidth="139.0" text="New Group">
 					<HBox.margin>

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

@@ -14,7 +14,7 @@ import java.io.Serializable;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class Attachment implements Serializable {
+public final class Attachment implements Serializable {
 
 	/**
 	 * Defines the type of the attachment.

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

@@ -1,15 +1,25 @@
 package envoy.data;
 
+import java.io.File;
+import java.io.IOException;
 import java.util.*;
+import java.util.function.Function;
+import java.util.logging.Level;
+import java.util.stream.Collectors;
 
-import envoy.exception.EnvoyException;
+import envoy.util.EnvoyLog;
 
 /**
  * Manages all application settings that are set during application startup by
- * either loading them from the {@link Properties} file
+ * either loading them from the {@link Properties} file (default values)
  * {@code client.properties} or parsing them from the command line arguments of
- * the application.<br>
+ * the application.
- * <br>
+ * <p>
+ * All items inside the {@code Config} are supposed to either be supplied over
+ * default value or over command line argument. Developers that fail to provide
+ * default values will be greeted with an error message the next time they try
+ * to start Envoy...
+ * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>Config.java</strong><br>
  * Created: <strong>12 Oct 2019</strong><br>
@@ -21,60 +31,109 @@ public class Config {
 
 	protected Map<String, ConfigItem<?>> items = new HashMap<>();
 
+	private boolean modificationDisabled;
+
+	protected Config(String folderName) {
+		final var rootDirectory = new File(System.getProperty("user.home"), folderName);
+		put("homeDirectory", "home", File::new);
+		((ConfigItem<File>) get("homeDirectory")).setValue(rootDirectory);
+		put("fileLevelBarrier", "fb", Level::parse);
+		put("consoleLevelBarrier", "cb", Level::parse);
+	}
+
 	/**
 	 * Parses config items from a properties object.
 	 *
 	 * @param properties the properties object to parse
 	 * @since Envoy Common v0.1-beta
 	 */
-	public void load(Properties properties) {
+	private void load(Properties properties) {
-		items.entrySet()
+		items.entrySet().stream().filter(e -> properties.containsKey(e.getKey()))
-			.stream()
+				.forEach(e -> e.getValue().parse(properties.getProperty(e.getKey())));
-			.filter(e -> properties.containsKey(e.getKey()))
-			.forEach(e -> e.getValue().parse(properties.getProperty(e.getKey())));
 	}
 
 	/**
 	 * Parses config items from an array of command line arguments.
 	 *
 	 * @param args the command line arguments to parse
-	 * @throws EnvoyException if the command line arguments contain an unknown token
+	 * @throws IllegalStateException if a malformed command line argument has been
+	 *                               supplied
 	 * @since Envoy Common v0.1-beta
 	 */
-	public void load(String[] args) throws EnvoyException {
+	private void load(String[] args) {
 		for (int i = 0; i < args.length; i++)
-			for (ConfigItem<?> item : items.values())
+			for (final ConfigItem<?> item : items.values())
 				if (args[i].startsWith("--")) {
-					if (args[i].length() == 2) throw new EnvoyException("Malformed command line argument at position " + i);
+					if (args[i].length() == 2)
+						throw new IllegalStateException(
+								"Malformed command line argument at position " + i + ": " + args[i]);
 					final String commandLong = args[i].substring(2);
 					if (item.getCommandLong().equals(commandLong)) {
 						item.parse(args[++i]);
 						break;
 					}
 				} else if (args[i].startsWith("-")) {
-					if (args[i].length() == 1) throw new EnvoyException("Malformed command line argument at position " + i);
+					if (args[i].length() == 1)
+						throw new IllegalStateException(
+								"Malformed command line argument at position " + i + ": " + args[i]);
 					final String commandShort = args[i].substring(1);
 					if (item.getCommandShort().equals(commandShort)) {
 						item.parse(args[++i]);
 						break;
 					}
-				} else throw new EnvoyException("Malformed command line argument at position " + i);
+				} else
+					throw new IllegalStateException(
+							"Malformed command line argument at position " + i + ": " + args[i]);
 	}
 
 	/**
-	 * Initializes config items from a map.
+	 * Supplies default values from the given .properties file and parses the
+	 * configuration from an array of command line arguments.
 	 *
-	 * @param items the items to include in this config
+	 * @param declaringClass     the class calling this method
+	 * @param propertiesFilePath the path to where the .properties file can be found
+	 *                           - will be only the file name if it is located
+	 *                           directly inside the {@code src/main/resources}
+	 *                           folder
+	 * @param args               the command line arguments to parse
+	 * @throws IllegalStateException if this method is getting called again or if a
+	 *                               malformed command line argument has been
+	 *                               supplied
 	 * @since Envoy Common v0.1-beta
 	 */
-	public void load(Map<String, ConfigItem<?>> items) { this.items.putAll(items); }
+	public void loadAll(Class<?> declaringClass, String propertiesFilePath, String[] args) {
+		if (modificationDisabled)
+			throw new IllegalStateException("Cannot change config after isInitialized has been called");
+		// Load the defaults from the given .properties file first
+		final var properties = new Properties();
+		try {
+			properties.load(declaringClass.getClassLoader().getResourceAsStream(propertiesFilePath));
+		} catch (final IOException e) {
+			EnvoyLog.getLogger(Config.class).log(Level.SEVERE, "An error occurred when reading in the configuration: ",
+					e);
+		}
+		load(properties);
+
+		// Override configuration values with command line arguments
+		if (args.length > 0)
+			load(args);
+
+		// Check if all configuration values have been initialized
+		isInitialized();
+		// Disable further editing of the config
+		modificationDisabled = true;
+	}
 
 	/**
-	 * @return {@code true} if all mandatory config items are initialized
+	 * @throws IllegalStateException if a {@link ConfigItem} has not been
+	 *                               initialized
 	 * @since Envoy Common v0.1-beta
 	 */
-	public boolean isInitialized() {
+	private void isInitialized() {
-		return items.values().stream().filter(ConfigItem::isMandatory).map(ConfigItem::get).noneMatch(Objects::isNull);
+		if (items.values().stream().map(ConfigItem::get).anyMatch(Objects::isNull))
+			throw new IllegalStateException("config item(s) has/ have not been initialized:"
+					+ items.values().stream().filter(configItem -> configItem.get() == null)
+							.map(ConfigItem::getCommandLong).collect(Collectors.toSet()));
 	}
 
 	/**
@@ -82,5 +141,46 @@ public class Config {
 	 * @return the config item with the specified name
 	 * @since Envoy Common v0.1-beta
 	 */
-	public ConfigItem<?> get(String name) { return items.get(name); }
+	public ConfigItem<?> get(String name) {
+		return items.get(name);
+	}
+
+	/**
+	 * Shorthand for <br>
+	 * {@code items.put(commandName, new ConfigItem<>(commandName, commandShort, parseFunction, defaultValue))}.
+	 *
+	 * @param <T>           the type of the {@link ConfigItem}
+	 * @param commandName   the key for this config item as well as its long name
+	 * @param commandShort  the abbreviation of this config item
+	 * @param parseFunction the {@code Function<String, T>} that parses the value
+	 *                      from a string
+	 * @since Envoy Common v0.2-beta
+	 */
+	protected <T> void put(String commandName, String commandShort, Function<String, T> parseFunction) {
+		items.put(commandName, new ConfigItem<>(commandName, commandShort, parseFunction));
+	}
+
+	/**
+	 * @return the directory in which all local files are saves
+	 * @since Envoy Client v0.2-beta
+	 */
+	public File getHomeDirectory() {
+		return (File) items.get("homeDirectory").get();
+	}
+
+	/**
+	 * @return the minimal {@link Level} to log inside the log file
+	 * @since Envoy Client v0.2-beta
+	 */
+	public Level getFileLevelBarrier() {
+		return (Level) items.get("fileLevelBarrier").get();
+	}
+
+	/**
+	 * @return the minimal {@link Level} to log inside the console
+	 * @since Envoy Client v0.2-beta
+	 */
+	public Level getConsoleLevelBarrier() {
+		return (Level) items.get("consoleLevelBarrier").get();
+	}
 }

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

@@ -4,8 +4,10 @@ import java.util.function.Function;
 
 /**
  * Contains a single {@link Config} value as well as the corresponding command
- * line arguments and its default value.<br>
+ * line arguments and its default value.
- * <br>
+ * <p>
+ * All {@code ConfigItem}s are automatically mandatory.
+ * <p>
  * Project: <strong>envoy-clientChess</strong><br>
  * File: <strong>ConfigItem.javaEvent.java</strong><br>
  * Created: <strong>21.12.2019</strong><br>
@@ -14,11 +16,10 @@ import java.util.function.Function;
  * @param <T> the type of the config item's value
  * @since Envoy Common v0.1-beta
  */
-public class ConfigItem<T> {
+public final class ConfigItem<T> {
 
 	private final String				commandLong, commandShort;
 	private final Function<String, T>	parseFunction;
-	private final boolean				mandatory;
 
 	private T value;
 
@@ -29,30 +30,12 @@ public class ConfigItem<T> {
 	 * @param commandShort  the short command line argument to set this value
 	 * @param parseFunction the {@code Function<String, T>} that parses the value
 	 *                      from a string
-	 * @param defaultValue  the optional default value to set before parsing
-	 * @param mandatory     indicated that this config item must be initialized with
-	 *                      a non-null value
-	 * @since Envoy Common v0.1-beta
-	 */
-	public ConfigItem(String commandLong, String commandShort, Function<String, T> parseFunction, T defaultValue, boolean mandatory) {
-		this.commandLong	= commandLong;
-		this.commandShort	= commandShort;
-		this.parseFunction	= parseFunction;
-		this.mandatory		= mandatory;
-		value				= defaultValue;
-	}
-
-	/**
-	 * Initializes an optional {@link ConfigItem} without a default value.
-	 *
-	 * @param commandLong   the long command line argument to set this value
-	 * @param commandShort  the short command line argument to set this value
-	 * @param parseFunction the {@code Function<String, T>} that parses the value
-	 *                      from a string
 	 * @since Envoy Common v0.1-beta
 	 */
 	public ConfigItem(String commandLong, String commandShort, Function<String, T> parseFunction) {
-		this(commandLong, commandShort, parseFunction, null, false);
+		this.commandLong	= commandLong;
+		this.commandShort	= commandShort;
+		this.parseFunction	= parseFunction;
 	}
 
 	/**
@@ -84,9 +67,8 @@ public class ConfigItem<T> {
 	public T get() { return value; }
 
 	/**
-	 * @return {@code true} if this {@link ConfigItem} is mandatory for successful
+	 * @param value the value to set
-	 *         application initialization
+	 * @since Envoy Common v0.2-beta
-	 * @since Envoy Common v0.1-beta
 	 */
-	public boolean isMandatory() { return mandatory; }
+	protected void setValue(T value) { this.value = value; }
 }

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

@@ -12,7 +12,7 @@ import java.io.Serializable;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class IDGenerator implements Serializable {
+public final class IDGenerator implements Serializable {
 
 	private final long	end;
 	private long		current;

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

@@ -16,13 +16,13 @@ import envoy.data.Message.MessageStatus;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class MessageBuilder {
+public final class MessageBuilder {
 
 	// Mandatory properties without default values
 	private final long senderID, recipientID;
 
 	// Properties with default values
-	private long					id;
+	private final long				id;
 	private Instant					creationDate, receivedDate, readDate;
 	private String					text;
 	private Attachment				attachment;
@@ -69,11 +69,11 @@ public class MessageBuilder {
 	 */
 	public MessageBuilder(Message msg, long recipientID, IDGenerator iDGenerator) {
 		this(msg.getRecipientID(), recipientID, iDGenerator.next());
-		this.attachment		= msg.getAttachment();
+		attachment		= msg.getAttachment();
-		this.creationDate	= Instant.now();
+		creationDate	= Instant.now();
-		this.forwarded		= true;
+		forwarded		= true;
-		this.text			= msg.getText();
+		text			= msg.getText();
-		this.status			= MessageStatus.WAITING;
+		status			= MessageStatus.WAITING;
 	}
 
 	/**
@@ -128,7 +128,7 @@ public class MessageBuilder {
 	 * @since Envoy Common v0.2-alpha
 	 */
 	public GroupMessage buildGroupMessage(Group group) {
-		var memberStatuses = new HashMap<Long, Message.MessageStatus>();
+		final var memberStatuses = new HashMap<Long, Message.MessageStatus>();
 		group.getContacts().forEach(user -> memberStatuses.put(user.getID(), MessageStatus.WAITING));
 		return buildGroupMessage(group, memberStatuses);
 	}

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

@@ -17,7 +17,7 @@ import java.util.function.Consumer;
  * @author Kai S. K. Engelbart
  * @since Envoy v0.2-alpha
  */
-public class EventBus {
+public final class EventBus {
 
 	/**
 	 * Contains all event handler instances registered at this event bus as values

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

@@ -15,7 +15,7 @@ import envoy.data.User;
  * @author Leon Hofmeister
  * @since Envoy Common v0.1-beta
  */
-public class GroupCreation extends Event<String> {
+public final class GroupCreation extends Event<String> {
 
 	private final Set<Long> initialMemberIDs;
 

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

@@ -0,0 +1,25 @@
+package envoy.event;
+
+/**
+ * Used to communicate with a client that his request to create a group might
+ * have been rejected as it might be disabled on his current server.
+ * <p>
+ * Project: <strong>common</strong><br>
+ * File: <strong>GroupCreationResult.java</strong><br>
+ * Created: <strong>22.08.2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.2-beta
+ */
+public class GroupCreationResult extends Event<Boolean> {
+
+	private static final long serialVersionUID = 1L;
+
+	/**
+	 * Creates a new {@code GroupCreationResult}.
+	 *
+	 * @param success whether the GroupCreation sent before was successful
+	 * @since Envoy Common v0.2-beta
+	 */
+	public GroupCreationResult(boolean success) { super(success); }
+}

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

@@ -13,7 +13,7 @@ import envoy.data.Message.MessageStatus;
  * @author Maximilian Käfer
  * @since Envoy Common v0.1-beta
  */
-public class GroupMessageStatusChange extends MessageStatusChange {
+public final class GroupMessageStatusChange extends MessageStatusChange {
 
 	private final long memberID;
 

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

@@ -17,7 +17,7 @@ import envoy.data.User;
  * @author Leon Hofmeister
  * @since Envoy Common v0.1-beta
  */
-public class GroupResize extends Event<User> {
+public final class GroupResize extends Event<User> {
 
 	private final long				groupID;
 	private final ElementOperation	operation;

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

@@ -11,7 +11,7 @@ package envoy.event;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.3-alpha
  */
-public class HandshakeRejection extends Event<String> {
+public final class HandshakeRejection extends Event<String> {
 
 	/**
 	 * Select this value if a given password hash or user name was incorrect.

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

@@ -11,7 +11,7 @@ package envoy.event;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.3-alpha
  */
-public class IDGeneratorRequest extends Event.Valueless {
+public final class IDGeneratorRequest extends Event.Valueless {
 
 	private static final long serialVersionUID = 1431107413883364583L;
 }

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

@@ -11,7 +11,7 @@ package envoy.event;
  * @author Leon Hofmeister
  * @since Envoy Client v0.2-beta
  */
-public class IsTyping extends Event<Long> {
+public final class IsTyping extends Event<Long> {
 
 	private final long destinationID;
 

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

@@ -11,7 +11,7 @@ package envoy.event;
  * @author Leon Hofmeister
  * @since Envoy Common v0.2-beta
  */
-public class IssueProposal extends Event<String> {
+public final class IssueProposal extends Event<String> {
 
 	private final String	description;
 	private final boolean	bug;

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

@@ -14,7 +14,7 @@ import envoy.data.Contact;
  * @author Leon Hofmeister
  * @since Envoy Common v0.1-beta
  */
-public class NameChange extends Event<String> {
+public final class NameChange extends Event<String> {
 
 	private final long id;
 

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

@@ -0,0 +1,17 @@
+package envoy.event;
+
+/**
+ * This event is used so that the server can tell the client that attachments
+ * will be filtered out.
+ * <p>
+ * Project: <strong>common</strong><br>
+ * File: <strong>NoAttachments.java</strong><br>
+ * Created: <strong>22.08.2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.2-beta
+ */
+public class NoAttachments extends Event.Valueless {
+
+	private static final long serialVersionUID = 1L;
+}

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

@@ -10,7 +10,7 @@ import envoy.data.Contact;
  * @author Leon Hofmeister
  * @since Envoy Common v0.2-beta
  */
-public class PasswordChangeRequest extends Event<String> {
+public final class PasswordChangeRequest extends Event<String> {
 
 	private final long		id;
 	private final String	oldPassword;

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

@@ -11,7 +11,7 @@ package envoy.event;
  * @author Leon Hofmeister
  * @since Envoy Common v0.2-beta
  */
-public class PasswordChangeResult extends Event<Boolean> {
+public final class PasswordChangeResult extends Event<Boolean> {
 
 	private static final long serialVersionUID = 1L;
 

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

@@ -8,7 +8,7 @@ package envoy.event;
  * @author Leon Hofmeister
  * @since Envoy Common v0.2-beta
  */
-public class ProfilePicChange extends Event<byte[]> {
+public final class ProfilePicChange extends Event<byte[]> {
 
 	private final long id;
 

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

@@ -11,7 +11,7 @@ import envoy.data.User.UserStatus;
  * @author Leon Hofmeister
  * @since Envoy Common v0.2-alpha
  */
-public class UserStatusChange extends Event<UserStatus> {
+public final class UserStatusChange extends Event<UserStatus> {
 
 	private final long id;
 

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

@@ -14,7 +14,7 @@ import envoy.event.Event;
  * @author Maximilian Käfer
  * @since Envoy Common v0.2-alpha
  */
-public class ContactOperation extends Event<Contact> {
+public final class ContactOperation extends Event<Contact> {
 
 	private final ElementOperation operationType;
 

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

@@ -12,7 +12,7 @@ import envoy.event.Event;
  * @author Maximilian Käfer
  * @since Envoy Common v0.2-alpha
  */
-public class UserSearchRequest extends Event<String> {
+public final class UserSearchRequest extends Event<String> {
 
 	private static final long serialVersionUID = 0L;
 

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

@@ -15,7 +15,7 @@ import envoy.event.Event;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class UserSearchResult extends Event<List<User>> {
+public final class UserSearchResult extends Event<List<User>> {
 
 	private static final long serialVersionUID = 0L;
 

common/src/main/java/envoy/exception/EnvoyException.java

@@ -8,7 +8,7 @@ package envoy.exception;
  * @author Kai S. K. Engelbart
  * @since Envoy v0.1-alpha
  */
-public class EnvoyException extends Exception {
+public final class EnvoyException extends Exception {
 
 	private static final long serialVersionUID = 2096147309395387479L;
 

common/src/main/java/envoy/util/Bounds.java

@@ -12,7 +12,7 @@ import java.util.regex.Pattern;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.1-beta
  */
-public class Bounds {
+public final class Bounds {
 
 	private Bounds() {}
 

common/src/main/java/envoy/util/EnvoyLog.java

@@ -12,18 +12,15 @@ import envoy.data.Config;
  * Configures the {@link java.util.logging} API to output the log into the
  * console and a log file.
  * <p>
- * Call the {@link EnvoyLog#attach(String)} method to configure a part of the
- * logger hierarchy.
- * <p>
  * Project: <strong>envoy-client</strong><br>
  * File: <strong>EnvoyLogger.java</strong><br>
- * Created: <strong>14 Dec 2019</strong><br>
+ * Created: <strong>14.12.2019</strong><br>
  *
  * @author Leon Hofmeister
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.1-beta
  */
-public class EnvoyLog {
+public final class EnvoyLog {
 
 	private static FileHandler		fileHandler;
 	private static StreamHandler	consoleHandler;
@@ -32,8 +29,7 @@ public class EnvoyLog {
 	private EnvoyLog() {}
 
 	/**
-	 * Initializes logging. Call this method before calling the
+	 * Initializes logging.
-	 * {@link EnvoyLog#attach(String)} method.
 	 *
 	 * @param config the config providing the console and log file barriers
 	 * @since Envoy Common v0.1-beta
@@ -45,18 +41,19 @@ public class EnvoyLog {
 		LogManager.getLogManager().reset();
 
 		// Configure log file
-		final File logFile = new File((File) config.get("homeDirectory").get(),
+		final File logFile = new File(config.getHomeDirectory(),
-				"log/envoy_user_" + DateTimeFormatter.ofPattern("yyyy-MM-dd--hh-mm-mm").format(LocalDateTime.now()) + ".log");
+				"log/" + DateTimeFormatter.ofPattern("yyyy-MM-dd--hh-mm").format(LocalDateTime.now()) + ".log");
 		logFile.getParentFile().mkdirs();
 
 		// Configure formatting
-		// Sample log entry: [2020-06-13 16:50:26] [INFORMATION] [envoy.client.ui.Startup] Closing connection...
+		// Sample log entry: [2020-06-13 16:50:26] [INFORMATION]
+		// [envoy.client.ui.Startup] Closing connection...
 		System.setProperty("java.util.logging.SimpleFormatter.format", "[%1$tF %1$tT] [%4$-7s] [%3$s] %5$s %6$s%n");
 		final SimpleFormatter formatter = new SimpleFormatter();
 
 		try {
 			fileHandler = new FileHandler(logFile.getAbsolutePath());
-			fileHandler.setLevel((Level) config.get("fileLevelBarrier").get());
+			fileHandler.setLevel(config.getFileLevelBarrier());
 			fileHandler.setFormatter(formatter);
 		} catch (SecurityException | IOException e) {
 			e.printStackTrace();
@@ -69,10 +66,11 @@ public class EnvoyLog {
 				flush();
 			}
 		};
-		consoleHandler.setLevel((Level) config.get("consoleLevelBarrier").get());
+		consoleHandler.setLevel(config.getConsoleLevelBarrier());
 		consoleHandler.setFormatter(formatter);
 
 		initialized = true;
+		EnvoyLog.attach("envoy");
 	}
 
 	/**
@@ -82,7 +80,7 @@ public class EnvoyLog {
 	 * @param path the path to the loggers to configure
 	 * @since Envoy Common v0.1-beta
 	 */
-	public static void attach(String path) {
+	private static void attach(String path) {
 		if (!initialized) throw new IllegalStateException("EnvoyLog is not initialized");
 
 		// Get root logger
@@ -105,22 +103,4 @@ public class EnvoyLog {
 	 * @since Envoy Common v0.1-beta
 	 */
 	public static Logger getLogger(Class<?> logClass) { return Logger.getLogger(logClass.getCanonicalName()); }
-
-	/**
-	 * Defines the logger level required for a record to be written to the log file.
-	 *
-	 * @param fileLevelBarrier the log file level
-	 * @since Envoy Common v0.1-beta
-	 */
-	public static void setFileLevelBarrier(Level fileLevelBarrier) { if (fileHandler != null) fileHandler.setLevel(fileLevelBarrier); }
-
-	/**
-	 * Defines the logger level required for a record to be written to the console.
-	 *
-	 * @param consoleLevelBarrier the console logger level
-	 * @since Envoy Common v0.1-beta
-	 */
-	public static void setConsoleLevelBarrier(Level consoleLevelBarrier) {
-		if (consoleHandler != null) consoleHandler.setLevel(consoleLevelBarrier);
-	}
 }

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

@@ -12,7 +12,7 @@ import java.io.*;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class SerializationUtils {
+public final class SerializationUtils {
 
 	private SerializationUtils() {}
 

server/src/main/java/envoy/server/Startup.java

@@ -1,16 +1,13 @@
 package envoy.server;
 
-import java.io.File;
 import java.io.IOException;
-import java.util.HashMap;
 import java.util.Set;
 import java.util.logging.Level;
 
 import com.jenkov.nioserver.Server;
 
-import envoy.data.Config;
-import envoy.data.ConfigItem;
 import envoy.server.data.PersistenceManager;
+import envoy.server.data.ServerConfig;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectMessageProcessor;
 import envoy.server.net.ObjectMessageReader;
@@ -27,26 +24,12 @@ import envoy.util.EnvoyLog;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class Startup {
+public final class Startup {
 
 	/**
-	 * Initializes the logger with a new config instance.
+	 * Stores the configuration used for the whole server
-	 *
-	 * @since Envoy Server Standalone v0.1-beta
 	 */
-	private static void initLogging() {
+	public static final ServerConfig config = ServerConfig.getInstance();
-		final var items = new HashMap<String, ConfigItem<?>>();
-		items.put("homeDirectory",
-				new ConfigItem<>("homeDirectory", "h", File::new, new File(System.getProperty("user.home"), ".envoy-server"), true));
-		items.put("fileLevelBarrier", new ConfigItem<>("fileLevelBarrier", "fb", Level::parse, Level.WARNING, true));
-		items.put("consoleLevelBarrier", new ConfigItem<>("consoleLevelBarrier", "cb", Level::parse, Level.FINEST, true));
-
-		final var config = new Config();
-		config.load(items);
-
-		EnvoyLog.initialize(config);
-		EnvoyLog.attach("envoy");
-	}
 
 	/**
 	 * Starts the server.
@@ -57,7 +40,13 @@ public class Startup {
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
 	public static void main(String[] args) throws IOException {
-		initLogging();
+		try {
+			config.loadAll(Startup.class, "server.properties", args);
+			EnvoyLog.initialize(config);
+		} catch (final IllegalStateException e) {
+			EnvoyLog.getLogger(Startup.class).log(Level.SEVERE, "Error loading configuration values: ", e);
+			System.exit(1);
+		}
 
 		final var server = new Server(8080, ObjectMessageReader::new,
 				new ObjectMessageProcessor(Set.of(new LoginCredentialProcessor(),
@@ -84,8 +73,8 @@ public class Startup {
 		server.start();
 		server.getSocketProcessor().registerSocketIdListener(ConnectionManager.getInstance());
 
-		if (args.length == 0 || !args[0].equalsIgnoreCase("no-enter-to-stop")) {
+		if (config.isEnterToStop()) {
-			System.out.println("Press the return key to stop the server...");
+			System.out.println("Press Enter to stop the server...");
 			System.in.read();
 			System.out.println("Stopped");
 			System.exit(0);

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

@@ -14,7 +14,7 @@ import javax.persistence.Table;
  */
 @Entity
 @Table(name = "configuration")
-public class ConfigItem {
+public final class ConfigItem {
 
 	@Id
 	private String	key;

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

@@ -28,7 +28,7 @@ import javax.persistence.NamedQuery;
 		query = "SELECT g FROM Group g WHERE g.creationDate > :lastSeen AND :user MEMBER OF g.contacts"
 	)
 })
-public class Group extends Contact {
+public final class Group extends Contact {
 
 	/**
 	 * Named query retrieving a group by name (parameter {@code :name}).

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

@@ -24,7 +24,7 @@ import envoy.data.Group;
 			+ "OR m.status = envoy.data.Message$MessageStatus.READ AND m.readDate > :lastSeen "
 			+ "OR m.lastStatusChangeDate > :lastSeen)"
 )
-public class GroupMessage extends Message {
+public final class GroupMessage extends Message {
 
 	/**
 	 * Named query retrieving pending group messages sent to a group containing a

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

@@ -1,6 +1,7 @@
 package envoy.server.data;
 
 import static envoy.data.Message.MessageStatus.*;
+import static envoy.server.Startup.config;
 
 import java.time.Instant;
 
@@ -104,7 +105,7 @@ public class Message {
 		sender			= persistenceManager.getUserByID(message.getSenderID());
 		recipient		= persistenceManager.getContactByID(message.getRecipientID());
 		forwarded		= message.isForwarded();
-		if (message.hasAttachment()) {
+		if (config.isAttachmentSupportEnabled() && message.hasAttachment()) {
 			final var messageAttachment = message.getAttachment();
 			attachment		= messageAttachment.getData();
 			attachmentName	= messageAttachment.getName();

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

@@ -19,7 +19,7 @@ import envoy.server.net.ConnectionManager;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class PersistenceManager {
+public final class PersistenceManager {
 
 	private final EntityManager		entityManager	= Persistence.createEntityManagerFactory("envoy").createEntityManager();
 	private final EntityTransaction	transaction		= entityManager.getTransaction();

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

@@ -0,0 +1,96 @@
+package envoy.server.data;
+
+import static java.util.function.Function.identity;
+
+import envoy.data.Config;
+
+/**
+ * Project: <strong>server</strong><br>
+ * File: <strong>ServerConfig.java</strong><br>
+ * Created: <strong>21.08.2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Server v0.2-beta
+ */
+public final class ServerConfig extends Config {
+
+	private static ServerConfig config;
+
+	/**
+	 * @return the singleton instance of the server config
+	 * @since Envoy Client v0.1-beta
+	 */
+	public static ServerConfig getInstance() { return config == null ? config = new ServerConfig() : config; }
+
+	private ServerConfig() {
+		super(".envoy-server");
+		put("enter-to-stop", "dev-stop", Boolean::parseBoolean);
+		// parameters for issue reporting
+		put("issueCreationURL", "i-url", identity());
+		put("issueAuthToken", "i-token", identity());
+		put("userMadeLabel", "l-um", identity());
+		put("bugLabel", "l-b", identity());
+		put("featureLabel", "l-f", identity());
+		// enabling/ disabling several processors
+		put("enableIssueReporting", "e-ir", Boolean::parseBoolean);
+		put("enableGroups", "e-g", Boolean::parseBoolean);
+		put("enableAttachments", "e-a", Boolean::parseBoolean);
+	}
+
+	/**
+	 * @return true if this server should be stoppable by pressing enter
+	 * @since Envoy Server v0.2-beta
+	 */
+	public Boolean isEnterToStop() { return (Boolean) items.get("enter-to-stop").get(); }
+
+	/**
+	 * @return {@code true} if issue reporting is enabled
+	 * @since Envoy Client v0.3-alpha
+	 */
+	public Boolean isIssueReportingEnabled() { return (Boolean) items.get("enableIssueReporting").get(); }
+
+	/**
+	 * @return {@code true} if attachment support has been enabled
+	 * @since Envoy Client v0.3-alpha
+	 */
+	public Boolean isAttachmentSupportEnabled() { return (Boolean) items.get("enableAttachments").get(); }
+
+	/**
+	 * @return {@code true} if group support has been enabled
+	 * @since Envoy Client v0.3-alpha
+	 */
+	public Boolean isGroupSupportEnabled() { return (Boolean) items.get("enableGroups").get(); }
+
+	/**
+	 * @return the URL where issues should be uploaded to
+	 * @since Envoy Client v0.1-alpha
+	 */
+	public String getIssueReportingURL() { return (String) items.get("issueCreationURL").get(); }
+
+	/**
+	 * @return the String representation for the "{@code user made}" - label
+	 * @since Envoy Client v0.1-alpha
+	 */
+	public String getUserMadeLabel() { return (String) items.get("userMadeLabel").get(); }
+
+	/**
+	 * @return the String representation for the "{@code user made}" - label
+	 * @since Envoy Client v0.1-alpha
+	 */
+	public String getBugLabel() { return (String) items.get("bugLabel").get(); }
+
+	/**
+	 * @return the String representation for the "{@code user made}" - label
+	 * @since Envoy Client v0.1-alpha
+	 */
+	public String getFeatureLabel() { return (String) items.get("featureLabel").get(); }
+
+	/**
+	 * @return the authorization token used to authenticate to
+	 *         {@link ServerConfig#getIssueReportingURL()}. If null,
+	 *         authorization is expected to occur via a query_param or via a basic
+	 *         user-password-combination
+	 * @since Envoy Server v0.2-beta
+	 */
+	public String getIssueAuthToken() { return (String) items.get("issueAuthToken").get(); }
+}

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

@@ -36,7 +36,7 @@ import envoy.data.User.UserStatus;
 		query = "SELECT u FROM User u WHERE (lower(u.name) LIKE lower(:searchPhrase) AND u <> :context AND :context NOT MEMBER OF u.contacts)"
 	)
 })
-public class User extends Contact {
+public final class User extends Contact {
 
 	/**
 	 * Named query retrieving a user by name (parameter {@code :name}).

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

@@ -19,7 +19,7 @@ import envoy.server.processors.UserStatusChangeProcessor;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class ConnectionManager implements ISocketIdListener {
+public final class ConnectionManager implements ISocketIdListener {
 
 	/**
 	 * Contains all socket IDs that have not yet performed a handshake / acquired

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

@@ -25,7 +25,7 @@ import envoy.util.EnvoyLog;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class ObjectMessageProcessor implements IMessageProcessor {
+public final class ObjectMessageProcessor implements IMessageProcessor {
 
 	private final Set<ObjectProcessor<?>> processors;
 

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

@@ -19,7 +19,7 @@ import envoy.util.SerializationUtils;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class ObjectMessageReader implements IMessageReader {
+public final class ObjectMessageReader implements IMessageReader {
 
 	private List<Message>	completeMessages	= new ArrayList<>();
 	private Message			nextMessage;

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

@@ -22,7 +22,7 @@ import envoy.util.SerializationUtils;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class ObjectWriteProxy {
+public final class ObjectWriteProxy {
 
 	private final WriteProxy writeProxy;
 

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

@@ -17,7 +17,7 @@ import envoy.util.EnvoyLog;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class ContactOperationProcessor implements ObjectProcessor<ContactOperation> {
+public final class ContactOperationProcessor implements ObjectProcessor<ContactOperation> {
 
 	private static final ConnectionManager connectionManager = ConnectionManager.getInstance();
 	private static final Logger				logger				= EnvoyLog.getLogger(ContactOperationProcessor.class);

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

@@ -1,9 +1,12 @@
 package envoy.server.processors;
 
+import static envoy.server.Startup.config;
+
 import java.util.HashSet;
 
 import envoy.event.ElementOperation;
 import envoy.event.GroupCreation;
+import envoy.event.GroupCreationResult;
 import envoy.event.contact.ContactOperation;
 import envoy.server.data.Contact;
 import envoy.server.data.PersistenceManager;
@@ -18,14 +21,17 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-beta
  */
-public class GroupCreationProcessor implements ObjectProcessor<GroupCreation> {
+public final class GroupCreationProcessor implements ObjectProcessor<GroupCreation> {
 
 	private final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 	private final ConnectionManager		connectionManager	= ConnectionManager.getInstance();
 
 	@Override
 	public void process(GroupCreation groupCreation, long socketID, ObjectWriteProxy writeProxy) {
-		envoy.server.data.Group group = new envoy.server.data.Group();
+		// Don't allow the creation of groups if manually disabled
+		writeProxy.write(socketID, new GroupCreationResult(config.isGroupSupportEnabled()));
+		if (!config.isGroupSupportEnabled()) return;
+		final envoy.server.data.Group group = new envoy.server.data.Group();
 		group.setName(groupCreation.get());
 		group.setContacts(new HashSet<>());
 		groupCreation.getInitialMemberIDs().stream().map(persistenceManager::getUserByID).forEach(group.getContacts()::add);

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

@@ -1,6 +1,7 @@
 package envoy.server.processors;
 
 import static envoy.data.Message.MessageStatus.*;
+import static envoy.server.Startup.config;
 
 import java.time.Instant;
 import java.util.Collections;
@@ -10,6 +11,7 @@ import javax.persistence.EntityExistsException;
 
 import envoy.data.GroupMessage;
 import envoy.event.MessageStatusChange;
+import envoy.event.NoAttachments;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
@@ -23,7 +25,7 @@ import envoy.util.EnvoyLog;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-beta
  */
-public class GroupMessageProcessor implements ObjectProcessor<GroupMessage> {
+public final class GroupMessageProcessor implements ObjectProcessor<GroupMessage> {
 
 	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();
 	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
@@ -47,17 +49,29 @@ public class GroupMessageProcessor implements ObjectProcessor<GroupMessage> {
 			writeProxy.write(socketID, new MessageStatusChange(groupMessage));
 		}
 
+		// message attachment will be automatically removed if disabled in config
+		final var groupMessageServer = new envoy.server.data.GroupMessage(groupMessage, Instant.now());
+		// Telling the server to reload the message without the attachment and telling
+		// the client not to send anymore attachments
+		if (!config.isAttachmentSupportEnabled() && groupMessage.hasAttachment()) {
+			groupMessage = groupMessageServer.toCommon();
+			writeProxy.write(socketID, new NoAttachments());
+		}
+
+		// This is needed unfortunately because of f***ing lambda restrictions ("must be
+		// fINaL oR EFfEcTivELy FiNAl")
+		final var groupMessageCopy = groupMessage;
 		// Deliver the message to the recipients that are online
 		writeProxy.writeToOnlineContacts(
-				persistenceManager.getGroupByID(groupMessage.getRecipientID())
+				persistenceManager.getGroupByID(groupMessageCopy.getRecipientID())
 					.getContacts()
 					.stream()
-					.filter(c -> c.getID() != groupMessage.getSenderID()),
+					.filter(c -> c.getID() != groupMessageCopy.getSenderID()),
-				groupMessage);
+				groupMessageCopy);
 
 		try {
-			PersistenceManager.getInstance().addMessage(new envoy.server.data.GroupMessage(groupMessage, Instant.now()));
+			PersistenceManager.getInstance().addMessage(groupMessageServer);
-		} catch (EntityExistsException e) {
+		} catch (final EntityExistsException e) {
 			logger.warning("Received a groupMessage with an ID that already exists");
 		}
 	}

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

@@ -24,7 +24,7 @@ import envoy.util.EnvoyLog;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-beta
  */
-public class GroupMessageStatusChangeProcessor implements ObjectProcessor<GroupMessageStatusChange> {
+public final class GroupMessageStatusChangeProcessor implements ObjectProcessor<GroupMessageStatusChange> {
 
 	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();
 	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();

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

@@ -14,7 +14,7 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-beta
  */
-public class GroupResizeProcessor implements ObjectProcessor<GroupResize> {
+public final class GroupResizeProcessor implements ObjectProcessor<GroupResize> {
 
 	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();

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

@@ -17,7 +17,7 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class IDGeneratorRequestProcessor implements ObjectProcessor<IDGeneratorRequest> {
+public final class IDGeneratorRequestProcessor implements ObjectProcessor<IDGeneratorRequest> {
 
 	private static final long ID_RANGE = 200;
 

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

@@ -18,7 +18,7 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Leon Hofmeister
  * @since Envoy Server v0.2-beta
  */
-public class IsTypingProcessor implements ObjectProcessor<IsTyping> {
+public final class IsTypingProcessor implements ObjectProcessor<IsTyping> {
 
 	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();
 	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();

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

@@ -1,5 +1,7 @@
 package envoy.server.processors;
 
+import static envoy.server.Startup.config;
+
 import java.io.IOException;
 import java.net.HttpURLConnection;
 import java.net.URL;
@@ -21,29 +23,34 @@ import envoy.util.EnvoyLog;
  * @author Leon Hofmeister
  * @since Envoy Server v0.2-beta
  */
-public class IssueProposalProcessor implements ObjectProcessor<IssueProposal> {
+public final class IssueProposalProcessor implements ObjectProcessor<IssueProposal> {
 
-	private static boolean		issueReportingEnabled	= true;
+	private static final Logger logger = EnvoyLog.getLogger(IssueProposalProcessor.class);
-	private static final Logger	logger					= EnvoyLog.getLogger(IssueProposalProcessor.class);
 
 	@Override
 	public void process(IssueProposal issueProposal, long socketID, ObjectWriteProxy writeProxy) throws IOException {
 		// Do nothing if manually disabled
-		if (!issueReportingEnabled) return;
+		if (!config.isIssueReportingEnabled()) return;
 		try {
-			final var	url			= new URL(
+			final var	url			= new URL(config.getIssueReportingURL());
-					"https://git.kske.dev/api/v1/repos/zdm/envoy/issues?access_token=6d8ec2a72d64cbaf6319434aa2e7caf0130701b3");
 			final var	connection	= (HttpURLConnection) url.openConnection();
 			connection.setRequestMethod("POST");
 			connection.setRequestProperty("Content-Type", "application/json; utf-8");
 			connection.setRequestProperty("Accept", "application/json");
+			// Two types of authorization are currently supported: access token as
+			// query param or access token as authorization header
+			final var authenticationToken = config.getIssueAuthToken();
+			if (authenticationToken != null) {
+				final String auth = "token " + authenticationToken;
+				connection.setRequestProperty("Authorization", auth);
+			}
 			connection.setDoOutput(true);
 
-			final var json = String.format("{\"title\":\"%s\",\"body\":\"%s\",\"labels\":[240, %d]}",
+			final var json = String.format("{\"title\":\"%s\",\"body\":\"%s\",\"labels\":[%s, %s]}",
 					issueProposal.get(),
 					issueProposal.getDescription(),
-					// Label 240 should be user-made, label 117 bug and label 119 feature
+					config.getUserMadeLabel(),
-					issueProposal.isBug() ? 117 : 119);
+					issueProposal.isBug() ? config.getBugLabel() : config.getFeatureLabel());
 			try (final var os = connection.getOutputStream()) {
 				final byte[] input = json.getBytes("utf-8");
 				os.write(input, 0, input.length);
@@ -51,29 +58,9 @@ public class IssueProposalProcessor implements ObjectProcessor<IssueProposal> {
 			final var status = connection.getResponseCode();
 			if (status == 201) logger.log(Level.INFO, "Successfully created an issue");
 			else logger.log(Level.WARNING,
-					String.format("Tried creating an issue for %s but received status code %d - Request params:title=%s,description=%s,json=%s",
+					String.format("Tried creating an issue for %s but received status code %d - Request params:%s", url, status, json));
-							url,
-							status,
-							issueProposal.get(),
-							issueProposal.getDescription(),
-							json));
 		} catch (final IOException e) {
 			logger.log(Level.WARNING, "An error occurred while creating an issue: ", e);
 		}
 	}
-
-	/**
-	 * @return whether issue reporting is enabled
-	 * @since Envoy Server v0.2-beta
-	 */
-	public static boolean isIssueReportingEnabled() { return issueReportingEnabled; }
-
-	/**
-	 * @param issueReportingEnabled whether issue reporting should be enabled - true
-	 *                              by default
-	 * @since Envoy Server v0.2-beta
-	 */
-	public static void setIssueReportingEnabled(boolean issueReportingEnabled) {
-		IssueProposalProcessor.issueReportingEnabled = issueReportingEnabled;
-	}
 }

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

@@ -1,5 +1,7 @@
 package envoy.server.processors;
 
+import static envoy.server.Startup.config;
+
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -7,6 +9,7 @@ import javax.persistence.EntityExistsException;
 
 import envoy.data.Message;
 import envoy.event.MessageStatusChange;
+import envoy.event.NoAttachments;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
@@ -23,7 +26,7 @@ import envoy.util.EnvoyLog;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class MessageProcessor implements ObjectProcessor<Message> {
+public final class MessageProcessor implements ObjectProcessor<Message> {
 
 	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();
@@ -35,6 +38,11 @@ public class MessageProcessor implements ObjectProcessor<Message> {
 
 		// Convert to server message
 		final var serverMessage = new envoy.server.data.Message(message);
+		// Telling the server to reload the message without the attachment
+		if (!config.isAttachmentSupportEnabled() && message.hasAttachment()) {
+			message = serverMessage.toCommon();
+			writeProxy.write(socketID, new NoAttachments());
+		}
 
 		try {
 
@@ -54,7 +62,7 @@ public class MessageProcessor implements ObjectProcessor<Message> {
 				// Note that the exact time stamp might differ slightly
 				writeProxy.write(socketID, new MessageStatusChange(message));
 			}
-		} catch (EntityExistsException e) {
+		} catch (final EntityExistsException e) {
 			logger.log(Level.WARNING, "Received " + message + " with an ID that already exists!");
 		}
 	}

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

@@ -19,7 +19,7 @@ import envoy.util.EnvoyLog;
  * @author Leon Hofmeister
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class MessageStatusChangeProcessor implements ObjectProcessor<MessageStatusChange> {
+public final class MessageStatusChangeProcessor implements ObjectProcessor<MessageStatusChange> {
 
 	private final ConnectionManager		connectionManager	= ConnectionManager.getInstance();
 	private final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();

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

@@ -15,7 +15,7 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Leon Hofmeister
  * @since Envoy Server Standalone v0.1-beta
  */
-public class NameChangeProcessor implements ObjectProcessor<NameChange> {
+public final class NameChangeProcessor implements ObjectProcessor<NameChange> {
 
 	private static final PersistenceManager persistenceManager = PersistenceManager.getInstance();
 

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

@@ -18,7 +18,7 @@ import envoy.util.EnvoyLog;
  * @author Leon Hofmeister
  * @since Envoy Server v0.2-beta
  */
-public class PasswordChangeRequestProcessor implements ObjectProcessor<PasswordChangeRequest> {
+public final class PasswordChangeRequestProcessor implements ObjectProcessor<PasswordChangeRequest> {
 
 	@Override
 	public void process(PasswordChangeRequest event, long socketID, ObjectWriteProxy writeProxy) throws IOException {

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

@@ -13,7 +13,7 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Leon Hofmeister
  * @since Envoy Server v0.2-beta
  */
-public class ProfilePicChangeProcessor implements ObjectProcessor<ProfilePicChange> {
+public final class ProfilePicChangeProcessor implements ObjectProcessor<ProfilePicChange> {
 
 	@Override
 	public void process(ProfilePicChange event, long socketID, ObjectWriteProxy writeProxy) throws IOException {}

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

@@ -20,7 +20,7 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class UserSearchProcessor implements ObjectProcessor<UserSearchRequest> {
+public final class UserSearchProcessor implements ObjectProcessor<UserSearchRequest> {
 
 	/**
 	 * Writes a list of contacts to the client containing all {@link Contact}s

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

@@ -19,7 +19,7 @@ import envoy.util.EnvoyLog;
  * @author Leon Hofmeister
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChange> {
+public final class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChange> {
 
 	private static ObjectWriteProxy writeProxy;
 

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

@@ -19,7 +19,7 @@ import javax.crypto.spec.PBEKeySpec;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-beta
  */
-public class PasswordUtil {
+public final class PasswordUtil {
 
 	private static final int	ITERATIONS				= 1000;
 	private static final int	KEY_LENGTH				= 64 * 8;

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

@@ -13,7 +13,7 @@ import java.util.regex.Pattern;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-beta
  */
-public class VersionUtil {
+public final class VersionUtil {
 
 	/**
 	 * The minimal client version compatible with this server.

server/src/main/resources/server.properties

@@ -0,0 +1,16 @@
+enter-to-stop=true
+enableAttachments=true
+enableGroups=true
+enableIssueReporting=true
+# git.kske.dev config
+issueCreationURL=https://git.kske.dev/api/v1/repos/zdm/envoy/issues?access_token=6d8ec2a72d64cbaf6319434aa2e7caf0130701b3
+userMadeLabel=240
+bugLabel=117
+featureLabel=119
+# api.github.com config - supply an additional auth token
+#issueCreationURL=https://api.github.com/repos/informatik-ag-ngl/envoy/issues
+#userMadeLabel="user made"
+#bugLabel="bug"
+#featureLabel="feature"
+consoleLevelBarrier=FINEST
+fileLevelBarrier=WARNING