Move placeholder item to public ItemUtils

Author: NichtStudioCode

invui/src/main/java/xyz/xenondevs/invui/internal/menu/CustomMerchantMenu.java

@@ -16,9 +16,9 @@
 import org.bukkit.entity.Player;
 import org.jspecify.annotations.Nullable;
 import xyz.xenondevs.invui.internal.network.PacketListener;
-import xyz.xenondevs.invui.internal.util.ItemUtils2;
 import xyz.xenondevs.invui.internal.util.MathUtils;
 import xyz.xenondevs.invui.item.Item;
+import xyz.xenondevs.invui.util.ItemUtils;
 import xyz.xenondevs.invui.window.MerchantWindow;
 
 import java.lang.invoke.MethodHandle;
@@ -141,9 +141,9 @@ private MerchantOffer toMerchantOffer(MerchantWindow.Trade trade) {
 
     private ItemStack toItemStack(@Nullable Item item) {
         if (item == null)
-            return CraftItemStack.unwrap(ItemUtils2.getNonEmptyPlaceholder());
+            return CraftItemStack.unwrap(ItemUtils.getPlaceholder());
 
-        var itemStack = CraftItemStack.unwrap(ItemUtils2.nonEmpty(item.getItemProvider(player).get(player.locale())));
+        var itemStack = CraftItemStack.unwrap(ItemUtils.takeOrPlaceholder(item.getItemProvider(player).get(player.locale())));
         // add random tag value to prevent client-side insertion of matching items
         itemStack.update(
             DataComponents.CUSTOM_DATA,

invui/src/main/java/xyz/xenondevs/invui/internal/util/ItemUtils2.java

@@ -2,15 +2,13 @@
 
 import io.papermc.paper.datacomponent.DataComponentType;
 import io.papermc.paper.datacomponent.DataComponentTypes;
-import net.kyori.adventure.key.Key;
 import net.minecraft.core.component.DataComponents;
 import net.minecraft.world.item.component.BundleContents;
 import org.bukkit.Material;
 import org.bukkit.Registry;
 import org.bukkit.craftbukkit.inventory.CraftItemStack;
 import org.bukkit.inventory.ItemStack;
 import org.jspecify.annotations.Nullable;
-import xyz.xenondevs.invui.item.ItemBuilder;
 import xyz.xenondevs.invui.util.ItemUtils;
 
 import java.util.ArrayList;
@@ -23,30 +21,6 @@
 @SuppressWarnings("UnstableApiUsage")
 public class ItemUtils2 {
 
-    private static final ItemStack NON_EMPTY_PLACEHOLDER = new ItemBuilder(Material.BARRIER)
-        .hideTooltip(true)
-        .set(DataComponentTypes.ITEM_MODEL, Key.key("air"))
-        .build();
-    
-    /**
-     * Returns the copy of the non-empty placeholder item, which should be used to replace empty slots.
-     *
-     * @return the non-empty placeholder item
-     */
-    public static ItemStack getNonEmptyPlaceholder() {
-        return NON_EMPTY_PLACEHOLDER.clone();
-    }
-    
-    /**
-     * Returns the given item stack if it is not empty, otherwise the non-empty placeholder item.
-     *
-     * @param itemStack the item stack
-     * @return the non-empty item stack
-     */
-    public static ItemStack nonEmpty(@Nullable ItemStack itemStack) {
-        return ItemUtils.isEmpty(itemStack) ? getNonEmptyPlaceholder() : itemStack;
-    }
-    
     /**
      * Creates a new list where all intermediary empty item stacks are replaced with the non-empty placeholder item
      * and all trailing empty item stacks are removed.
@@ -68,7 +42,7 @@ public static List<ItemStack> withoutIntermediaryEmpties(List<@Nullable ItemStac
         for (int i = 0; i <= lastNonNull; i++) {
             var itemStack = items.get(i);
             if (ItemUtils.isEmpty(itemStack)) {
-                sanitized.add(getNonEmptyPlaceholder());
+                sanitized.add(ItemUtils.getPlaceholder());
             } else {
                 sanitized.add(itemStack);
             }

invui/src/main/java/xyz/xenondevs/invui/util/ItemUtils.java

@@ -1,14 +1,26 @@
 package xyz.xenondevs.invui.util;
 
+import io.papermc.paper.datacomponent.DataComponentTypes;
+import net.kyori.adventure.key.Key;
 import org.bukkit.Material;
 import org.bukkit.inventory.ItemStack;
 import org.jspecify.annotations.Nullable;
+import xyz.xenondevs.invui.item.ItemBuilder;
+import xyz.xenondevs.invui.item.ItemProvider;
+import xyz.xenondevs.invui.item.ItemWrapper;
 
 /**
  * Generic item-related utilities.
  */
+@SuppressWarnings("UnstableApiUsage")
 public class ItemUtils {
 
+    private static final ItemStack PLACEHOLDER = new ItemBuilder(Material.BARRIER)
+        .hideTooltip(true)
+        .set(DataComponentTypes.ITEM_MODEL, Key.key("air"))
+        .build();
+    private static final ItemWrapper PLACEHOLDER_PROVIDER = new ItemWrapper(PLACEHOLDER);
+    
     /**
      * Checks whether the given {@link ItemStack} is empty.
      * <p>
@@ -68,4 +80,33 @@ public static boolean isEmpty(@Nullable ItemStack itemStack) {
         return itemStack.clone();
     }
 
+    /**
+     * Returns a copy of the non-empty placeholder item, which is an invisible non-air item stack.
+     *
+     * @return the non-empty placeholder item
+     */
+    public static ItemStack getPlaceholder() {
+        return PLACEHOLDER.clone();
+    }
+    
+    /**
+     * Gets an {@link ItemProvider} for the {@link #getPlaceholder() placeholder} item.
+     *
+     * @return the placeholder item provider
+     */
+    public static ItemProvider getPlaceholderProvider() {
+        return PLACEHOLDER_PROVIDER;
+    }
+    
+    /**
+     * Returns the given item stack if it is not {@link #isEmpty(ItemStack) empty},
+     * otherwise the {@link #getPlaceholder() placeholder} item.
+     *
+     * @param itemStack the item stack
+     * @return the non-empty item stack
+     */
+    public static ItemStack takeOrPlaceholder(@Nullable ItemStack itemStack) {
+        return isEmpty(itemStack) ? getPlaceholder() : itemStack;
+    }
+    
 }

invui/src/main/java/xyz/xenondevs/invui/window/CartographyWindowImpl.java

@@ -8,9 +8,9 @@
 import xyz.xenondevs.invui.gui.AbstractGui;
 import xyz.xenondevs.invui.gui.Gui;
 import xyz.xenondevs.invui.internal.menu.CustomCartographyMenu;
-import xyz.xenondevs.invui.internal.util.ItemUtils2;
 import xyz.xenondevs.invui.state.Property;
 import xyz.xenondevs.invui.util.ColorPalette;
+import xyz.xenondevs.invui.util.ItemUtils;
 
 import java.awt.image.BufferedImage;
 import java.util.HashSet;
@@ -59,7 +59,7 @@ public CartographyWindowImpl(
     @Override
     protected void setMenuItem(int slot, @Nullable ItemStack itemStack) {
         if (slot == 0 || slot == 1) {
-            super.setMenuItem(slot, ItemUtils2.nonEmpty(itemStack));
+            super.setMenuItem(slot, ItemUtils.takeOrPlaceholder(itemStack));
         } else {
             super.setMenuItem(slot, itemStack);
         }

invui/src/main/java/xyz/xenondevs/invui/window/StonecutterWindowImpl.java

@@ -13,6 +13,7 @@
 import xyz.xenondevs.invui.internal.menu.CustomStonecutterMenu;
 import xyz.xenondevs.invui.internal.util.ItemUtils2;
 import xyz.xenondevs.invui.state.MutableProperty;
+import xyz.xenondevs.invui.util.ItemUtils;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -106,7 +107,7 @@ public void setSelectedSlot(int i) {
     @Override
     protected void setMenuItem(int slot, @Nullable ItemStack itemStack) {
         if (slot == 0) {
-            super.setMenuItem(0, ItemUtils2.nonEmpty(itemStack));
+            super.setMenuItem(0, ItemUtils.takeOrPlaceholder(itemStack));
         } else if (slot >= 38 && slot < buttonsGui.getSize() + 38) {
             buttons[slot - 38] = itemStack;
             buttonsDirty = true;