Added onStructureGrow event, thanks to md-5.

By: Nathan Adams <dinnerbone@dinnerbone.com>

paper-api/src/main/java/org/bukkit/TreeType.java

@@ -1,12 +1,14 @@
 package org.bukkit;
 
 /**
- * Tree type.
+ * Tree and organic structure types.
  */
 public enum TreeType {
     TREE,
     BIG_TREE,
     REDWOOD,
     TALL_REDWOOD,
-    BIRCH
+    BIRCH,
+    RED_MUSHROOM,
+    BROWN_MUSHROOM
 }

paper-api/src/main/java/org/bukkit/event/Event.java

@@ -593,6 +593,12 @@ public abstract class Event implements Serializable {
          * @see org.bukkit.event.world.PortalCreateEvent
          */
         PORTAL_CREATE (Category.WORLD),
+        /**
+         * Called when an organic structure attempts to grow (Sapling -> Tree), (Mushroom -> Huge Mushroom), naturally or using bonemeal.
+         *
++        * @see org.bukkit.event.world.TreeGrowEvent
+         */
+        STRUCTURE_GROW (Category.WORLD),
 
         /**
          * ENTITY EVENTS

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

@@ -0,0 +1,85 @@
+package org.bukkit.event.world;
+
+import java.util.List;
+import org.bukkit.Location;
+import org.bukkit.TreeType;
+import org.bukkit.block.BlockState;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+
+/**
+ * Event that is called when an organic structure attempts to grow (Sapling -> Tree), (Mushroom -> Huge Mushroom), naturally or using bonemeal.
+ */
+public class StructureGrowEvent extends WorldEvent implements Cancellable {
+    private static final long serialVersionUID = 1L;
+    private boolean cancelled = false;
+    private Location location;
+    private final TreeType species;
+    private final boolean bonemeal;
+    private Player player;
+    private List<BlockState> blocks;
+
+    public StructureGrowEvent(Location location, final TreeType species, final boolean bonemeal, Player player, List<BlockState> blocks) {
+        super(Type.STRUCTURE_GROW, location.getWorld());
+        this.location = location;
+        this.species = species;
+        this.bonemeal = bonemeal;
+        this.player = player;
+        this.blocks = blocks;
+    }
+
+    /**
+     * Gets the location of the structure.
+     *
+     * @return Location of the structure
+     */
+    public Location getLocation() {
+        return location;
+    }
+
+    /**
+     * Gets the species type (birch, normal, pine, red mushroom, brown mushroom)
+     *
+     * @return Structure species
+     */
+    public TreeType getSpecies() {
+        return species;
+    }
+
+    /**
+     * Checks if structure  was grown using bonemeal.
+     *
+     * @return True if the structure was grown using bonemeal.
+     */
+    public boolean isFromBonemeal() {
+        return bonemeal;
+    }
+
+    /**
+     * Gets the player that created the structure.
+     *
+     * @return Player that created the structure, null if was not created manually
+     */
+    public Player getPlayer() {
+        return player;
+    }
+
+    /**
+     * Gets an ArrayList of all blocks associated with the structure.
+     *
+     * @return ArrayList of all blocks associated with the structure.
+     */
+    public List<BlockState> getBlocks() {
+        return blocks;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    @Override
+    public void setCancelled(boolean cancel) {
+        cancelled = cancel;
+    }
+}

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

@@ -56,8 +56,7 @@ public class WorldListener implements Listener {
      *
      * @param event Relevant event details
      */
-    public void onWorldInit(WorldInitEvent event) {
-    }
+    public void onWorldInit(WorldInitEvent event) {}
 
     /**
      * Called when a World is loaded
@@ -72,4 +71,10 @@ public class WorldListener implements Listener {
      * @param event Relevant event details
      */
     public void onWorldUnload(WorldUnloadEvent event) { }
+    /**
+     * Event that is called when an organic structure attempts to grow (Sapling -> Tree), (Mushroom -> Huge Mushroom), naturally or using bonemeal.
+     *
+     * @param event Relevant event details
+     */
+    public void onStructureGrow(StructureGrowEvent event) {}
 }

paper-api/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java

@@ -677,6 +677,12 @@ public class JavaPluginLoader implements PluginLoader {
                     ((WorldListener) listener).onPortalCreate((PortalCreateEvent) event);
                 }
             };
+        case STRUCTURE_GROW:
+            return new EventExecutor() {
+                public void execute(Listener listener, Event event) {
+                    ((WorldListener) listener).onStructureGrow((StructureGrowEvent) event);
+                }
+            };
 
         // Painting Events
         case PAINTING_PLACE: