Add ShulkerDuplicateEvent

paper-api/src/main/java/io/papermc/paper/event/entity/ShulkerDuplicateEvent.java

@@ -0,0 +1,68 @@
+package io.papermc.paper.event.entity;
+
+import org.bukkit.entity.Shulker;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.entity.EntityEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Fired when a shulker duplicates itself by spawning a new shulker.
+ * <p>
+ * The event is fired prior to the newly created shulker, accessible via {@link #getEntity()}, being added to the world.
+ */
+@NullMarked
+public class ShulkerDuplicateEvent extends EntityEvent implements Cancellable {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final Shulker parent;
+    private boolean cancelled;
+
+    @ApiStatus.Internal
+    public ShulkerDuplicateEvent(final Shulker child, final Shulker parent) {
+        super(child);
+        this.parent = parent;
+    }
+
+    /**
+     * Provides the newly created shulker, which did not exist prior to the duplication.
+     * At the point of this event, said shulker is not part of the world yet.
+     *
+     * @return the newly duplicated shulker.
+     */
+    @Override
+    public Shulker getEntity() {
+        return (Shulker) super.getEntity();
+    }
+
+    /**
+     * Provides the "parent" of the freshly created shulker.
+     * The parent shulker is the one that initiated the duplication.
+     *
+     * @return the previously existing shulker which duplicated.
+     */
+    public Shulker getParent() {
+        return this.parent;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return this.cancelled;
+    }
+
+    @Override
+    public void setCancelled(final boolean cancel) {
+        this.cancelled = cancel;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}