Deprecated SlotModifier, replaced with SlotUpdater

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

@@ -2,6 +2,7 @@ package com.willfp.eco.core.gui.slot;
 
 import com.willfp.eco.core.gui.slot.functional.SlotHandler;
 import com.willfp.eco.core.gui.slot.functional.SlotModifier;
+import com.willfp.eco.core.gui.slot.functional.SlotUpdater;
 import org.bukkit.event.inventory.InventoryClickEvent;
 import org.jetbrains.annotations.NotNull;
 
@@ -106,8 +107,23 @@ public interface SlotBuilder {
      *
      * @param modifier The modifier.
      * @return The builder.
+     * @deprecated Use {@link SlotBuilder#setUpdater(SlotUpdater)} instead.
      */
-    SlotBuilder setModifier(@NotNull SlotModifier modifier);
+    @Deprecated
+    default SlotBuilder setModifier(@NotNull SlotModifier modifier) {
+        return setUpdater((player, menu, previous) -> {
+            modifier.modify(player, menu, previous);
+            return previous;
+        });
+    }
+
+    /**
+     * Set the ItemStack updater.
+     *
+     * @param updater The updater.
+     * @return The builder.
+     */
+    SlotBuilder setUpdater(@NotNull SlotUpdater updater);
 
     /**
      * Set slot to be a captive slot.

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

@@ -7,8 +7,11 @@ import org.jetbrains.annotations.NotNull;
 
 /**
  * Interface to run on slot modify.
+ *
+ * @deprecated Use {@link SlotUpdater} instead.
  */
 @FunctionalInterface
+@Deprecated
 public interface SlotModifier {
     /**
      * Performs this operation on the given arguments.

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

@@ -0,0 +1,24 @@
+package com.willfp.eco.core.gui.slot.functional;
+
+import com.willfp.eco.core.gui.menu.Menu;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Interface to run on slot update.
+ */
+@FunctionalInterface
+public interface SlotUpdater {
+    /**
+     * Performs this operation on the given arguments.
+     *
+     * @param player   The player.
+     * @param menu     The menu.
+     * @param previous The previous ItemStack.
+     * @return The new ItemStack.
+     */
+    ItemStack update(@NotNull Player player,
+                     @NotNull Menu menu,
+                     @NotNull ItemStack previous);
+}

eco-api/src/main/kotlin/com/willfp/eco/core/gui/GUIHelpers.kt

@@ -43,10 +43,18 @@ fun SlotBuilder.onMiddleClick(action: (InventoryClickEvent, Slot, Menu) -> Unit)
 
 /**
  * @see SlotBuilder.setModifier
+ * @deprecated Use SlotUpdater instead.
  */
+@Deprecated("Use SlotUpdater instead")
 fun SlotBuilder.setModifier(action: (Player, Menu, ItemStack) -> Unit): SlotBuilder =
     this.setModifier { a, b, c -> action(a, b, c) }
 
+/**
+ * @see SlotBuilder.setUpdater
+ */
+fun SlotBuilder.setUpdater(action: (Player, Menu, ItemStack) -> ItemStack): SlotBuilder =
+    this.setUpdater { a, b, c -> action(a, b, c) }
+
 /**
  * Kotlin builder for slots.
  */