Fix StackedItemSpawnEvent not called in some cases

UltimateStacker-API/src/main/java/com/craftaro/ultimatestacker/api/events/entity/StackedItemSpawnEvent.java

@@ -1,11 +1,14 @@
 package com.craftaro.ultimatestacker.api.events.entity;
 
 import com.craftaro.ultimatestacker.api.stack.entity.EntityStack;
+import org.bukkit.entity.Item;
 import org.bukkit.entity.LivingEntity;
 import org.bukkit.event.Cancellable;
 import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
 import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * Called before we spawn a stacked items
@@ -13,22 +16,59 @@ import org.bukkit.inventory.ItemStack;
 public class StackedItemSpawnEvent extends Event implements Cancellable {
 
     private static final HandlerList handlers = new HandlerList();
-    private final ItemStack item;
-    private final long amount;
+    private Item item;
+    private ItemStack itemStack;
+    private long amount;
     private boolean cancelled = false;
 
-    public StackedItemSpawnEvent(ItemStack item, long amount) {
+    /**
+     * Constructor
+     *
+     * @param item   Item that will be modified. Can be null if we spawn a new one
+     * @param itemStack ItemStack that will be spawned
+     * @param amount amount
+     */
+    public StackedItemSpawnEvent(@Nullable Item item, @NotNull ItemStack itemStack, long amount) {
         this.item = item;
+        this.itemStack = itemStack;
         this.amount = amount;
     }
 
     /**
-     * Get the item that will be spawned
+     * Get the item that will be modified
+     *
+     * @return Item
+     */
+    public @Nullable Item getItem() {
+        return item;
+    }
+
+    /**
+     * Set the item that will be spawned
+     *
+     * @param item Item
+     */
+    public void setItem(Item item) {
+        this.item = item;
+    }
+
+    /**
+     * Get the ItemStack that will be spawned
      *
      * @return ItemStack
      */
-    public ItemStack getItem() {
-        return item;
+    public @NotNull ItemStack getItemStack() {
+        return itemStack;
+    }
+
+    /**
+     * Set the item that will be spawned
+     *
+     * @param itemStack ItemStack
+     */
+    public void setItemStack(ItemStack itemStack) {
+        if (itemStack == null) throw new IllegalArgumentException("ItemStack cannot be null");
+        this.itemStack = itemStack;
     }
 
     /**
@@ -40,6 +80,15 @@ public class StackedItemSpawnEvent extends Event implements Cancellable {
         return amount;
     }
 
+    /**
+     * Set the amount of items that will be spawned
+     *
+     * @param amount amount
+     */
+    public void setAmount(long amount) {
+        this.amount = amount;
+    }
+
     @Override
     public HandlerList getHandlers() {
         return handlers;

UltimateStacker-API/src/main/java/com/craftaro/ultimatestacker/api/stack/item/StackedItemManager.java

@@ -24,9 +24,11 @@ public interface StackedItemManager {
      * Create a new StackedItem for the given item
      * @param item The item to create the stack for
      * @param amount The amount of items in the stack
-     * @return The StackedItem for the given Item
+     * @return The StackedItem for the given Item or
+     *         null if it could not be created or a
+     *         plugin cancelled the event
      */
-    @NotNull StackedItem createStack(Item item, int amount);
+    @Nullable StackedItem createStack(Item item, int amount);
 
     /**
      * Create a new StackedItem for the given ItemStack

UltimateStacker-Plugin/src/main/java/com.craftaro.ultimatestacker/stackable/item/StackedItemManagerImpl.java

@@ -34,7 +34,7 @@ public class StackedItemManagerImpl implements StackedItemManager {
         if (item.getType() == Material.AIR) return null;
         World world = location.getWorld();
         if (world == null) return null;
-        StackedItemSpawnEvent event = new StackedItemSpawnEvent(item, amount);
+        StackedItemSpawnEvent event = new StackedItemSpawnEvent(null, item, amount);
         Bukkit.getPluginManager().callEvent(event);
         if (event.isCancelled()) return null;
 
@@ -44,7 +44,10 @@ public class StackedItemManagerImpl implements StackedItemManager {
     }
 
     @Override
-    public @NotNull StackedItem createStack(Item item, int amount) {
+    public StackedItem createStack(Item item, int amount) {
+        StackedItemSpawnEvent event = new StackedItemSpawnEvent(item, item.getItemStack(), amount);
+        Bukkit.getPluginManager().callEvent(event);
+        if (event.isCancelled()) return null;
         return new StackedItemImpl(item, amount);
     }