SPIGOT-759: Add FireworkExplodeEvent.

nms-patches/EntityFireworks.patch

@@ -1 +1,11 @@
-
+--- a/net/minecraft/server/EntityFireworks.java
++++ b/net/minecraft/server/EntityFireworks.java
+@@ -78,7 +78,7 @@
+         }
+ 
+         if (!this.world.isClientSide && this.ticksFlown > this.expectedLifespan) {
+-            this.world.broadcastEntityEffect(this, (byte) 17);
++            if (!org.bukkit.craftbukkit.event.CraftEventFactory.callFireworkExplodeEvent(this).isCancelled()) this.world.broadcastEntityEffect(this, (byte) 17);
+             this.die();
+         }
+ 

src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -34,6 +34,7 @@ import org.bukkit.craftbukkit.util.CraftMagicNumbers;
 import org.bukkit.entity.Arrow;
 import org.bukkit.entity.Creeper;
 import org.bukkit.entity.EntityType;
+import org.bukkit.entity.Firework;
 import org.bukkit.entity.Horse;
 import org.bukkit.entity.LightningStrike;
 import org.bukkit.entity.LivingEntity;
@@ -946,4 +947,10 @@ public class CraftEventFactory {
         entityHuman.world.getServer().getPluginManager().callEvent(event);
         return (Cancellable) event;
     }
+
+    public static FireworkExplodeEvent callFireworkExplodeEvent(EntityFireworks firework) {
+        FireworkExplodeEvent event = new FireworkExplodeEvent((Firework) firework.getBukkitEntity());
+        firework.world.getServer().getPluginManager().callEvent(event);
+        return event;
+    }
 }