Add ItemFactory

plugins/civmodcore-paper/src/main/java/vg/civcraft/mc/civmodcore/inventory/items/ItemFactory.java

@@ -0,0 +1,70 @@
+package vg.civcraft.mc.civmodcore.inventory.items;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import javax.annotation.Nonnull;
+import lombok.experimental.UtilityClass;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftItemStack;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+
+/**
+ * Utility class that provides a means to construct {@link CraftItemStack CraftItemStacks} in lieu of
+ * {@link ItemStack#ItemStack(Material, int) new ItemStack(Material, Int)}. The reason being that
+ * {@link CraftItemStack CraftItemStacks} interact more efficiently with NMS than {@link ItemStack} does as the latter
+ * is entirely abstract in nature.
+ */
+@UtilityClass
+public class ItemFactory {
+
+	private static final Constructor<CraftItemStack> CRAFT_ITEM_STACK_CONSTRUCTOR;
+
+	static {
+		final Constructor<CraftItemStack> constructor;
+		try {
+			constructor = CraftItemStack.class.getDeclaredConstructor(
+					Material.class, Integer.TYPE, Short.TYPE, ItemMeta.class);
+			constructor.setAccessible(true);
+		}
+		catch (final NoSuchMethodException exception) {
+			throw new IllegalStateException(exception);
+		}
+		CRAFT_ITEM_STACK_CONSTRUCTOR = constructor;
+	}
+
+	/**
+	 * Creates a new {@link CraftItemStack} based on a given material.
+	 *
+	 * @param material The material of the item.
+	 * @return Returns a new instance of {@link CraftItemStack}.
+	 */
+	public static ItemStack createItemStack(@Nonnull final Material material) {
+		return createItemStack(material, 1);
+	}
+
+	/**
+	 * Creates a new {@link CraftItemStack} based on a given material.
+	 *
+	 * @param material The material of the item.
+	 * @param amount The item amount.
+	 * @return Returns a new instance of {@link CraftItemStack}.
+	 */
+	public static ItemStack createItemStack(@Nonnull final Material material, final int amount) {
+		if (material == null || !material.isItem()) { // Ignore highlighter
+			throw new IllegalArgumentException("Material must be a valid item material!");
+		}
+		if (amount <= 0 || amount > material.getMaxStackSize()) {
+			throw new IllegalArgumentException("Must have a valid item amount");
+		}
+		try {
+			return CRAFT_ITEM_STACK_CONSTRUCTOR.newInstance(material, amount,
+					(short) 0, Bukkit.getItemFactory().getItemMeta(material));
+		}
+		catch (final InvocationTargetException | InstantiationException | IllegalAccessException exception) {
+			throw new RuntimeException("Could not construct item stack", exception);
+		}
+	}
+
+}