Event System

The Hytale server implements an event system that allows mods to react to game events, modify behavior, and communicate with each other.

The system is built around a central EventBus that manages event registration and dispatch. Events can be:

• Synchronous (IEvent) - Handlers called immediately in priority order
• Asynchronous (IAsyncEvent) - Handlers use CompletableFuture for async processing
• Cancellable (ICancellable) - Handlers can prevent the action from occurring
• Keyed - Events filtered by key (world name, asset type, etc.)

Quick Reference

Task	Guide
Listen for events	Listening to Events
Create custom events	Creating Custom Events
Dispatch events	Dispatching Events
Event reference	Event Reference

Event Flow

1. Event Created - Code creates an event instance
2. Dispatcher Obtained - eventBus.dispatchFor(EventClass.class) or with key
3. Dispatch - dispatcher.dispatch(event) calls handlers in priority order
4. Keyed Matching - For keyed events, only matching listeners are called
5. Global Fallback - Global listeners receive all keyed events
6. Unhandled Fallback - Unhandled listeners only called if no keyed match
7. Result - For cancellable events, check event.isCancelled()

Package Structure

Built-in events by package:

Package	Description
com.hypixel.hytale.assetstore.event	Asset loading and hot-reload
com.hypixel.hytale.server.core.event.events	Core server (boot, shutdown)
com.hypixel.hytale.server.core.event.events.ecs	Block/item interactions
com.hypixel.hytale.server.core.event.events.entity	Entity lifecycle
com.hypixel.hytale.server.core.event.events.permissions	Permission changes
com.hypixel.hytale.server.core.event.events.player	Player actions
com.hypixel.hytale.server.core.plugin.event	Plugin lifecycle
com.hypixel.hytale.server.core.prefab.event	Prefab paste/place
com.hypixel.hytale.server.core.universe.world.events	World and chunks

See the Event Reference for a complete list of all events.