SPIGOT-2304: Add LootGenerateEvent

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-api/src/main/java/org/bukkit/event/world/LootGenerateEvent.java

@@ -0,0 +1,156 @@
+package org.bukkit.event.world;
+
+import java.util.Collection;
+import java.util.List;
+import org.bukkit.World;
+import org.bukkit.entity.Entity;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.entity.EntityDeathEvent;
+import org.bukkit.inventory.InventoryHolder;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.loot.LootContext;
+import org.bukkit.loot.LootTable;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Called when a {@link LootTable} is generated in the world for an
+ * {@link InventoryHolder}.
+ *
+ * This event is NOT currently called when an entity's loot table has been
+ * generated (use {@link EntityDeathEvent#getDrops()}, but WILL be called by
+ * plugins invoking
+ * {@link LootTable#fillInventory(org.bukkit.inventory.Inventory, java.util.Random, LootContext)}.
+ */
+public class LootGenerateEvent extends WorldEvent implements Cancellable {
+
+    private static final HandlerList handlers = new HandlerList();
+    private boolean cancelled;
+    private final Entity entity;
+    private final InventoryHolder inventoryHolder;
+    private final LootTable lootTable;
+    private final LootContext lootContext;
+    private final List<ItemStack> loot;
+    private final boolean plugin;
+
+    public LootGenerateEvent(@NotNull World world, @Nullable Entity entity, @Nullable InventoryHolder inventoryHolder, @NotNull LootTable lootTable, @NotNull LootContext lootContext, @NotNull List<ItemStack> items, boolean plugin) {
+        super(world);
+        this.entity = entity;
+        this.inventoryHolder = inventoryHolder;
+        this.lootTable = lootTable;
+        this.lootContext = lootContext;
+        this.loot = items;
+        this.plugin = plugin;
+    }
+
+    /**
+     * Get the entity used as context for loot generation (if applicable).
+     *
+     * For inventories where entities are not required to generate loot, such as
+     * hoppers, null will be returned.
+     *
+     * This is a convenience method for
+     * {@code getLootContext().getLootedEntity()}.
+     *
+     * @return the entity
+     */
+    @Nullable
+    public Entity getEntity() {
+        return entity;
+    }
+
+    /**
+     * Get the inventory holder in which the loot was generated.
+     *
+     * If the loot was generated as a result of the block being broken, the
+     * inventory holder will be null as this event is called post block break.
+     *
+     * @return the inventory holder
+     */
+    @Nullable
+    public InventoryHolder getInventoryHolder() {
+        return inventoryHolder;
+    }
+
+    /**
+     * Get the loot table used to generate loot.
+     *
+     * @return the loot table
+     */
+    @NotNull
+    public LootTable getLootTable() {
+        return lootTable;
+    }
+
+    /**
+     * Get the loot context used to provide context to the loot table's loot
+     * generation.
+     *
+     * @return the loot context
+     */
+    @NotNull
+    public LootContext getLootContext() {
+        return lootContext;
+    }
+
+    /**
+     * Set the loot to be generated. Null items will be treated as air.
+     *
+     * Note: the set collection is not the one which will be returned by
+     * {@link #getLoot()}.
+     *
+     * @param loot the loot to generate, null to clear all loot
+     */
+    public void setLoot(@Nullable Collection<ItemStack> loot) {
+        this.loot.clear();
+        if (loot != null) {
+            this.loot.addAll(loot);
+        }
+    }
+
+    /**
+     * Get a mutable list of all loot to be generated.
+     *
+     * Any items added or removed from the returned list will be reflected in
+     * the loot generation. Null items will be treated as air.
+     *
+     * @return the loot to generate
+     */
+    @NotNull
+    public List<ItemStack> getLoot() {
+        return loot;
+    }
+
+    /**
+     * Check whether or not this event was called as a result of a plugin
+     * invoking
+     * {@link LootTable#fillInventory(org.bukkit.inventory.Inventory, java.util.Random, LootContext)}.
+     *
+     * @return true if plugin caused, false otherwise
+     */
+    public boolean isPlugin() {
+        return plugin;
+    }
+
+    @Override
+    public void setCancelled(boolean cancel) {
+        this.cancelled = cancel;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    @NotNull
+    @Override
+    public HandlerList getHandlers() {
+        return handlers;
+    }
+
+    @NotNull
+    public static HandlerList getHandlerList() {
+        return handlers;
+    }
+}