Added Item_Model property and mechanism

plugin/src/main/java/com/denizenscript/denizen/objects/properties/PropertyRegistry.java

@@ -233,6 +233,9 @@ public static void registerMainProperties() {
             PropertyParser.registerProperty(ItemComponentsPatch.class, ItemTag.class);
             registerItemProperty(ItemCustomData.class, "custom_data");
         }
+        if (NMSHandler.getVersion().isAtLeast(NMSVersion.v1_21)) {
+            registerItemProperty(ItemItemModel.class, "item_model");
+        }
         registerItemProperty(ItemCustomModel.class, "custom_model_data");
         registerItemProperty(ItemChargedProjectile.class, "charged_projectiles");
         registerItemProperty(ItemEnchantments.class, "enchantments", "stored_enchantments");

plugin/src/main/java/com/denizenscript/denizen/objects/properties/item/ItemItemModel.java

@@ -0,0 +1,63 @@
+package com.denizenscript.denizen.objects.properties.item;
+
+import com.denizenscript.denizen.objects.ItemTag;
+import com.denizenscript.denizencore.objects.Mechanism;
+import com.denizenscript.denizencore.objects.core.ElementTag;
+import com.denizenscript.denizencore.objects.properties.PropertyParser;
+import org.bukkit.NamespacedKey;
+import org.bukkit.inventory.meta.ItemMeta;
+
+import java.util.List;
+
+public class ItemItemModel extends ItemProperty<ElementTag> {
+
+    // <--[property]
+    // @object ItemTag
+    // @name item_model
+    // @input ElementTag
+    // @description
+    // Controls the Item Model of the item.
+    // Use with no input to remove the Item Model.
+    // See also <@link tag ItemTag.has_item_model>
+    // -->
+    public static boolean describes(ItemTag item) {
+        return !item.getBukkitMaterial().isAir();
+    }
+
+    @Override
+    public ElementTag getPropertyValue() {
+        if (getItemMeta().hasItemModel()) {
+            return new ElementTag(getItemMeta().getItemModel().toString());
+        }
+        return null;
+    }
+
+    @Override
+    public void setPropertyValue(ElementTag value, Mechanism mechanism) {
+        ItemMeta meta = getItemMeta();
+        meta.setItemModel(mechanism.hasValue() ? NamespacedKey.fromString(value.asString()) : null);
+        setItemMeta(meta);
+    }
+
+    @Override
+    public String getPropertyId() {
+        return "item_model";
+    }
+
+    public static void register() {
+        autoRegisterNullable("item_model", ItemItemModel.class, ElementTag.class, false);
+
+        // <--[tag]
+        // @attribute <ItemTag.has_item_model>
+        // @returns ElementTag(Boolean)
+        // @mechanism ItemTag.item_model
+        // @group properties
+        // @description
+        // Returns whether the item has an Item Model set on it.
+        // See also <@link tag ItemTag.item_model>.
+        // -->
+        PropertyParser.registerTag(ItemItemModel.class, ElementTag.class, "has_item_model", (attribute, prop) -> {
+            return new ElementTag(prop.getItemMeta().hasItemModel());
+        });
+    }
+}