add DragonEggFormEvent

paper-api/src/main/java/io/papermc/paper/event/block/DragonEggFormEvent.java

@@ -0,0 +1,53 @@
+package io.papermc.paper.event.block;
+
+import org.bukkit.Material;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockState;
+import org.bukkit.boss.DragonBattle;
+import org.bukkit.entity.EnderDragon;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.block.BlockFormEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Called when the {@link EnderDragon} is defeated (killed) in a {@link DragonBattle},
+ * causing a {@link Material#DRAGON_EGG} (more formally: {@link #getNewState()})
+ * to possibly appear depending on {@link #isCancelled()}.
+ * <p>
+ * <b>This event might be cancelled by default depending on
+ * e.g. {@link DragonBattle#hasBeenPreviouslyKilled()} and server configuration.</b>
+ */
+@NullMarked
+public class DragonEggFormEvent extends BlockFormEvent {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final DragonBattle dragonBattle;
+
+    @ApiStatus.Internal
+    public DragonEggFormEvent(final Block block, final BlockState newState, final DragonBattle dragonBattle) {
+        super(block, newState);
+        this.dragonBattle = dragonBattle;
+    }
+
+    /**
+     * Gets the {@link DragonBattle} associated with this event.
+     * Keep in mind that the {@link EnderDragon} is already dead
+     * when this event is called.
+     *
+     * @return the dragon battle
+     */
+    public DragonBattle getDragonBattle() {
+        return this.dragonBattle;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}