Throw error for multiple cart actions in settings view

PlayWall/src/main/java/de/tobias/playpad/viewcontroller/actions/CartActionTypeViewController.java

@@ -17,7 +17,9 @@ import javafx.scene.control.ToggleGroup;
 import javafx.scene.layout.*;
 import org.controlsfx.control.SegmentedButton;
 
+import java.util.Arrays;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * Diese View ist die Basis für die Einstellunge für eine CartAction. Dabei enthällt diese View ein Grid aus Buttons (Carts), eine
@@ -113,17 +115,21 @@ public class CartActionTypeViewController extends NVC {
 			int currentY = data[1];
 
 			try {
-				List<Action> cartActions = mapping.getActionsForType(actionType);
-				for (Action action : cartActions) {
-					if (CartAction.getX(action) == currentX && CartAction.getY(action) == currentY) {
+				final List<Action> cartActions = mapping.getActionsForType(actionType).stream()
+						.filter(action -> CartAction.getX(action) == currentX && CartAction.getY(action) == currentY)
+						.collect(Collectors.toList());
+
+				if (cartActions.size() > 1) {
+					throw new IllegalArgumentException("Only one action allowed per pad. Currently " + cartActions.size() + " are registered for pad coordinate " + Arrays.toString(data));
+				}
+
+				final Action action = cartActions.get(0);
 				if (actionViewController != null) {
 					cartActionContainer.getChildren().setAll(actionViewController.getParent());
 					cartActionContainer.setVisible(true);
 					actionViewController.setCartAction(action);
 				}
 				parentController.showMapperFor(action);
-					}
-				}
 			} catch (NoSuchComponentException e) {
 				Logger.error(e);
 			}

PlayWall/src/main/java/de/tobias/playpad/viewcontroller/actions/CartActionViewController.java

 package de.tobias.playpad.viewcontroller.actions;
 
 import de.thecodelabs.midi.action.Action;
-import de.thecodelabs.utils.ui.NVC;
 import de.thecodelabs.utils.util.Localization;
 import de.tobias.playpad.Strings;
 import de.tobias.playpad.action.actions.CartAction;