Added captivator slots

eco-api/src/main/java/com/willfp/eco/core/gui/menu/Menu.java

@@ -4,8 +4,11 @@ import com.willfp.eco.core.Eco;
 import com.willfp.eco.core.gui.slot.Slot;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.List;
+
 /**
  * GUI version of {@link Inventory}.
  * <p>
@@ -44,6 +47,14 @@ public interface Menu {
      */
     Inventory open(@NotNull Player player);
 
+    /**
+     * Get captive items.
+     *
+     * @param player The player.
+     * @return The items.
+     */
+    List<ItemStack> getCaptiveItems(@NotNull Player player);
+
     /**
      * Create a builder with a given amount of rows.
      *

eco-api/src/main/java/com/willfp/eco/core/gui/slot/SlotBuilder.java

@@ -49,6 +49,13 @@ public interface SlotBuilder {
      */
     SlotBuilder onMiddleClick(@NotNull BiConsumer<InventoryClickEvent, Slot> action);
 
+    /**
+     * Set slot to be a captive slot.
+     *
+     * @return The builder.
+     */
+    SlotBuilder setCaptive();
+
     /**
      * Build the slot.
      *