Helper method for slot lookup added.

src/engine/gameManager/BuildingManager.java

@@ -27,6 +27,7 @@ import java.time.LocalDateTime;
 import java.time.ZoneId;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ThreadLocalRandom;
 
 public enum BuildingManager {
@@ -36,6 +37,17 @@ public enum BuildingManager {
     public static HashMap<Integer, ArrayList<BuildingLocation>> _stuckLocations;
     public static HashMap<Integer, ArrayList<BuildingLocation>> _slotLocations;
 
+    public static int getAvailableSlot(Building building) {
+
+        int numOfSlots = _slotLocations.get(building.meshUUID).size();
+
+        for (int i = 1; i < numOfSlots; i++) {
+            if (!building.getHirelings().containsValue(i))
+            return i;
+        }
+        return -1;
+    }
+
     public static boolean playerCanManage(PlayerCharacter player, Building building) {
 
         if (player == null)