prevent names longer than 16 chars

src/main/java/fr/insa/clavardator/ui/MainController.java

@@ -151,14 +151,18 @@ public class MainController implements Initializable {
 		Log.v(this.getClass().getSimpleName(), "Login shown");
 		mainContainer.setVisible(false);
 		loadingController.hide();
+		if (isError) {
 			Timer t = new Timer();
 			t.schedule(new TimerTask() {
 				@Override
 				public void run() {
-				openEditUsernameDialog(isError ? EditUsernameDialogController.Mode.ERROR : EditUsernameDialogController.Mode.INITIAL);
+					openEditUsernameDialog(EditUsernameDialogController.Mode.ERROR);
 					t.cancel();
 				}
 			}, 500);
+		} else {
+			openEditUsernameDialog(EditUsernameDialogController.Mode.INITIAL);
+		}
 	}
 
 	private void showError() {

src/main/java/fr/insa/clavardator/ui/dialogs/EditUsernameDialogController.java

@@ -45,6 +45,8 @@ public class EditUsernameDialogController implements Initializable {
 	private ButtonPressEvent cancelListener;
 	private UserList userList;
 
+	private final int MAX_LENGTH = 16;
+
 	@FXML
 	private void onConfirm() {
 		setLocked(true);
@@ -101,6 +103,10 @@ public class EditUsernameDialogController implements Initializable {
 	public void onUsernameChange(ObservableValue<? extends String> observable, String oldText, String newText) {
 		setFieldError(State.VALID);
 		confirmButton.setDisable(newText.isEmpty());
+		if (textField.getText().length() > MAX_LENGTH) {
+			String s = textField.getText().substring(0, MAX_LENGTH);
+			textField.setText(s);
+		}
 	}
 
 	public void setMode(Mode mode) {