Examples & Recipes

1public class WelcomePlugin extends JavaPlugin {
2    
3    public WelcomePlugin(JavaPluginInit init) {
4        super(init);
5    }
6    
7    @Override
8    protected void setup() {
9        getLogger().at(Level.INFO).log("WelcomePlugin loading...");
10    }
11    
12    @Override
13    protected void start() {
14        getEventRegistry().register(PlayerConnectEvent.class, this::onPlayerJoin);
15        getLogger().at(Level.INFO).log("WelcomePlugin started!");
16    }
17    
18    @Override
19    protected void shutdown() {
20        getLogger().at(Level.INFO).log("WelcomePlugin stopped.");
21    }
22    
23    private void onPlayerJoin(PlayerConnectEvent event) {
24        Player player = event.getPlayer();
25        
26        // Show welcome title (thread-safe)
27        showWelcomeTitle(player);
28        
29        // Spawn particles (thread-safe)
30        spawnWelcomeParticles(player);
31        
32        // Log the join
33        getLogger().at(Level.INFO).log("%s joined the server", player.getDisplayName());
34    }
35    
36    private void showWelcomeTitle(Player player) {
37        FormattedMessage title = new FormattedMessage(
38            "WELCOME",
39            null, null, null, null,
40            "#00FF88",
41            MaybeBool.True,   // bold
42            MaybeBool.False,  // italic
43            MaybeBool.False,  // monospace
44            MaybeBool.False,  // underlined
45            null, false
46        );
47        
48        FormattedMessage subtitle = new FormattedMessage(
49            player.getDisplayName(),
50            null, null, null, null,
51            "#AAAAAA",
52            MaybeBool.False,  // bold
53            MaybeBool.True,   // italic
54            MaybeBool.False,  // monospace
55            MaybeBool.False,  // underlined
56            null, false
57        );
58        
59        ShowEventTitle packet = new ShowEventTitle(
60            0.5f, 0.5f, 3.0f, null, true, title, subtitle
61        );
62        
63        player.getPlayerConnection().write(packet);
64    }
65    
66    private void spawnWelcomeParticles(Player player) {
67        TransformComponent transform = player.getTransformComponent();
68        Vector3d pos = transform.getPosition();
69        
70        SpawnParticleSystem packet = new SpawnParticleSystem(
71            "Sparkle",
72            new Position(pos.x, pos.y + 2, pos.z),
73            new Direction(0f, 0f, 0f),
74            2.0f,
75            null
76        );
77        
78        for (Player p : player.getWorld().getPlayers()) {
79            p.getPlayerConnection().write(packet);
80        }
81    }
82}

1public class ChatFilter {
2    
3    private final Set<String> bannedWords = new HashSet<>();
4    private final Map lastMessage = new ConcurrentHashMap<>();
5    private final long COOLDOWN_MS = 1000;  // 1 second
6    
7    public ChatFilter() {
8        bannedWords.add("badword1");
9        bannedWords.add("badword2");
10    }
11    
12    // Note: PlayerChatEvent is async and keyed by world name
13    public void handleChat(PlayerChatEvent event) {
14        PlayerRef sender = event.getSender();
15        String message = event.getContent().toLowerCase();
16        UUID uuid = sender.getUuid();
17        
18        // Check spam
19        long now = System.currentTimeMillis();
20        Long last = lastMessage.get(uuid);
21        
22        if (last != null && (now - last) < COOLDOWN_MS) {
23            event.setCancelled(true);
24            return;
25        }
26        
27        // Check banned words
28        for (String word : bannedWords) {
29            if (message.contains(word)) {
30                event.setCancelled(true);
31                return;
32            }
33        }
34        
35        // Update last message time
36        lastMessage.put(uuid, now);
37    }
38}

1public class SpeedCommand extends AbstractCommand {
2    
3    private final RequiredArg multiplierArg;
4    
5    public SpeedCommand() {
6        super("speed", "Set your movement speed");
7        this.multiplierArg = withRequiredArg(
8            "multiplier", 
9            "Speed multiplier (0.1 - 5.0)", 
10            ArgTypes.DOUBLE
11        );
12    }
13    
14    @Override
15    @Nullable
16    protected CompletableFuture execute(@Nonnull CommandContext ctx) {
17        if (!ctx.isPlayer()) {
18            ctx.sendMessage(Message.raw("Only players can use this command!"));
19            return null;
20        }
21        
22        double multiplier = ctx.get(multiplierArg);
23        
24        if (multiplier < 0.1 || multiplier > 5.0) {
25            ctx.sendMessage(Message.raw("Multiplier must be between 0.1 and 5.0"));
26            return null;
27        }
28        
29        Player player = ctx.senderAs(Player.class);
30        MovementSettings settings = MovementConfig.DEFAULT_MOVEMENT.toPacket();
31        
32        settings.baseSpeed = settings.baseSpeed * (float) multiplier;
33        settings.forwardWalkSpeedMultiplier *= (float) multiplier;
34        settings.forwardRunSpeedMultiplier *= (float) multiplier;
35        settings.forwardSprintSpeedMultiplier *= (float) multiplier;
36        
37        player.getPlayerConnection().write(new UpdateMovementSettings(settings));
38        ctx.sendMessage(Message.raw("Speed set to " + multiplier + "x"));
39        
40        return null;
41    }
42}