Automate switching between languages

src/main/resources/fxml/components/Menubar.fxml

@@ -5,6 +5,8 @@
 <?import javafx.scene.control.MenuItem?>
 <?import javafx.scene.control.Menu?>
 <?import javafx.scene.control.SeparatorMenuItem?>
+<?import javafx.scene.control.ToggleGroup?>
+<?import javafx.scene.control.RadioMenuItem?>
 
 <MenuBar
   fx:id="menubar"
@@ -24,10 +26,22 @@
         <MenuItem mnemonicParsing="false" text="Save" accelerator="Shortcut+s"/>
         <MenuItem mnemonicParsing="false" text="Save as" accelerator="Shortcut+S"/>
         <SeparatorMenuItem/>
+
+        <fx:define>
+          <ToggleGroup fx:id="languageToggleGroup"/>  
+        </fx:define>
+
         <Menu mnemonicParsing="false" text="Change programming language">
           <items>
-            <MenuItem mnemonicParsing="false" text="Java"/>
-            <MenuItem mnemonicParsing="false" text="Markdown"/>
+            <!-- TODO: Generate buttons based on classes -->
+            <RadioMenuItem text="Java"
+                           fx:id="toggleJava"
+                           onAction="#handleLanguageChange"
+                           toggleGroup="$languageToggleGroup"/>
+            <RadioMenuItem text="Markdown"
+                           fx:id="toggleMarkdown"
+                           onAction="#handleLanguageChange"
+                           toggleGroup="$languageToggleGroup"/>
           </items>
         </Menu>
         <SeparatorMenuItem/>