Implemented check to detect attempt to link 2 beacons

src/main/java/eu/ruekov/ruakij/LinkedBeaconTeleporters/linkedBeaconTeleporter/listener/OnPrepareItemCraftEvent.java

@@ -0,0 +1,11 @@
+package eu.ruekov.ruakij.LinkedBeaconTeleporters.linkedBeaconTeleporter.listener;
+
+import org.bukkit.inventory.CraftingInventory;
+import org.bukkit.inventory.InventoryView;
+
+public class OnPrepareItemCraftEvent {
+
+    public static void onPrepareItemCraftEvent(CraftingInventory what, InventoryView view, boolean isRepair){
+
+    }
+}

src/main/java/eu/ruekov/ruakij/LinkedBeaconTeleporters/listener/OnPrepareItemCraftEvent.java

@@ -14,5 +14,17 @@ public class OnPrepareItemCraftEvent implements Listener {
     @EventHandler(priority = EventPriority.LOW)
     public void onPrepareItemCraftEvent(CraftingInventory what, InventoryView view, boolean isRepair){
 
+        ItemStack[] matrix = what.getMatrix();
+
+        // Check if 2 beacons are in the crafting-slots
+        int beaconCount = 0;
+        for (ItemStack item : matrix) {
+            if(item.getType() == Material.BEACON)
+                beaconCount++;
+        }
+        if(beaconCount == 2){
+            // Exactly 2 beacons found
+            eu.ruekov.ruakij.LinkedBeaconTeleporters.linkedBeaconTeleporter.listener.OnPrepareItemCraftEvent.onPrepareItemCraftEvent(what, view, isRepair);
+        }
     }
 }