Pumpkin-Docs/docs/en/plugin-dev/migrating-from-bukkit/events.md
Alexander Medvedev 18dfb3c73e some addtions
2026-08-10 21:40:43 +02:00

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# Migrating Events from Bukkit
In Bukkit, events are handled by creating classes that implement `Listener` and annotating methods with `@EventHandler`.
In Pumpkin, event handlers are structs or objects registered explicitly via `context.register_event_handler(...)`. Pumpkin also differentiates between **Blocking** and **Non-blocking** events to maximize server concurrency.
---
## Key Differences
| Feature | Bukkit / Spigot | Pumpkin |
| :--- | :--- | :--- |
| **Listener Declaration** | `@EventHandler` annotation on methods | `EventHandler<E>` trait / interface implementation |
| **Registration** | `pm.registerEvents(listener, plugin)` | `context.register_event_handler(handler, priority, is_blocking)` |
| **Execution Model** | Main thread execution (`EventPriority`) | Choice between **Blocking** (sequential/cancellable) and **Non-blocking** (concurrent) |
| **Cancellation** | `event.setCancelled(true)` | `event.cancel()` on blocking events |
---
## Blocking vs. Non-Blocking Events in Pumpkin
Unlike Bukkit where all event handlers run sequentially on the main server thread, Pumpkin lets you specify whether an event handler is **blocking**:
```rust
// Registration signature in Rust:
context.register_event_handler(handler, priority, is_blocking)?;
```
- **Blocking (`is_blocking = true`)**: Executes in sequential priority order. Can modify event data (e.g. edit join message) or cancel the event.
- **Non-blocking (`is_blocking = false`)**: Executes concurrently across worker threads. Ideal for logging, metrics, or external notifications where cancellation is not needed.
---
## Code Comparison: Player Join Event
### 1. Bukkit Implementation (Java)
```java [JoinListener.java]
public class JoinListener implements Listener {
@EventHandler(priority = EventPriority.NORMAL)
public void onPlayerJoin(PlayerJoinEvent event) {
Player player = event.getPlayer();
event.setJoinMessage("Welcome " + player.getName() + " to the server!");
}
}
// In JavaPlugin:
// getServer().getPluginManager().registerEvents(new JoinListener(), this);
```
### 2. Pumpkin Implementations
::: code-group
```rust [Rust]
use pumpkin_plugin_api::{
Context, Plugin, PluginMetadata, Server,
events::{EventData, EventHandler, EventPriority, PlayerJoinEvent},
text::TextComponent,
};
struct JoinHandler;
impl EventHandler<PlayerJoinEvent> for JoinHandler {
fn handle<'a>(
&'a self,
_server: Server,
mut event: EventData<PlayerJoinEvent>,
) -> EventData<PlayerJoinEvent> {
event.join_message = TextComponent::text("Welcome to the Pumpkin server!");
event
}
}
pub struct MyPlugin;
impl Plugin for MyPlugin {
fn new() -> Self { MyPlugin }
fn metadata(&self) -> PluginMetadata {
PluginMetadata {
name: "join_plugin".into(),
version: "1.0.0".into(),
authors: vec!["Developer".into()],
description: "Join event handler".into(),
}
}
fn on_load(&mut self, context: Context) -> pumpkin_plugin_api::Result<()> {
// Register blocking event handler with Normal priority
context.register_event_handler(JoinHandler, EventPriority::Normal, true)?;
Ok(())
}
}
```
```python [Python]
from pumpkin_api import (
Plugin, PluginMetadata, register_plugin,
event, server, context
)
class MyPlugin(Plugin):
def metadata(self) -> PluginMetadata:
return PluginMetadata(name="join_plugin", version="1.0.0", authors=["Dev"], description="Join event")
def on_load(self, ctx: context.Context) -> None:
self.register_event(ctx, event.EventType.PLAYER_JOIN_EVENT, self.on_player_join)
def on_player_join(self, srv: server.Server, evt: event.PlayerJoinEventData) -> event.PlayerJoinEventData:
print(f"Player joined!")
return evt
register_plugin(MyPlugin)
```
:::