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Hytale Modding Docs

Registration

Registration

Section titled “Registration”

Package: com.hypixel.hytale.registry

public class Registration

A handle representing a single item registered with a Registry. Each Registration tracks whether it is still active and provides an unregister() method to remove itself. Registrations are lifecycle-aware: they become inactive either when explicitly unregistered or when the owning registry shuts down.

Fields

Section titled “Fields”
@Nonnull
protected final BooleanSupplier isEnabled

A supplier that returns true when the owning registry is still active. This is the registry’s enabled state, passed in during construction. When the registry calls shutdown(), this supplier starts returning false, causing isRegistered() to return false even if unregister() was never called.

@Nonnull
protected final Runnable unregister

A callback that performs the actual removal of this registration from the underlying system (e.g., removing an event listener from the EventBus, or removing a command from the dispatcher). Invoked by unregister() if the registration is still active.

private boolean registered = true

Internal flag tracking whether unregister() has been called. Starts as true and is set to false when unregister() executes.

Constructor

Section titled “Constructor”
public Registration(@Nonnull BooleanSupplier isEnabled, @Nonnull Runnable unregister)

Creates a registration with the given enabled supplier and unregister callback.

  • isEnabled — typically the owning Registry’s isEnabled() method reference. Used to determine whether the registration is still meaningful.
  • unregister — the callback that performs actual cleanup when unregister() is called (e.g., removing the listener, deregistering the command).

The registered flag is initially true.

Methods

Section titled “Methods”

unregister

Section titled “unregister”
public void unregister()

Removes this registration. The method checks two conditions before executing the unregister callback:

  1. The registered flag must be true (i.e., unregister() has not already been called).
  2. The isEnabled supplier must return true (i.e., the owning registry has not been shut down).

If both conditions are met, the unregister callback is invoked and the registered flag is set to false. If either condition fails, the method is a no-op. This design ensures:

  • Idempotent: calling unregister() multiple times is safe — the callback runs at most once.
  • Shutdown-safe: calling unregister() after the registry has shut down is a no-op rather than an error, because the registry’s shutdown already handled cleanup.

isRegistered

Section titled “isRegistered”
public boolean isRegistered()

Returns true only if both of the following are true:

  1. The registered flag is true (the registration has not been explicitly unregistered).
  2. The isEnabled supplier returns true (the owning registry is still active).

This means a registration can become inactive in two ways:

  • Explicit unregister — the plugin calls registration.unregister(), setting registered to false.
  • Registry shutdown — the owning registry shuts down, causing isEnabled to return false.

In both cases, isRegistered() returns false.

Lifecycle

Section titled “Lifecycle”

A Registration handle progresses through these states:

               register()
                   |
                   v
         +-------------------+
         | registered = true |
         | isEnabled = true  |
         |  isRegistered()   |
         |   returns true    |
         +-------------------+
              |           |
    unregister()    registry.shutdown()
              |           |
              v           v
         +-------------------+
         | registered = false|   (or isEnabled = false)
         |  isRegistered()   |
         |   returns false   |
         +-------------------+

  1. Active — created by Registry.register(). Both isRegistered() returns true and the underlying server-level registration is live.

  2. Manually unregistered — the plugin calls unregister(). The unregister callback runs, removing the registration from the server-level manager. isRegistered() returns false.

  3. Auto-unregistered on shutdown — when the plugin shuts down, PluginBase.cleanup() iterates the shared shutdown task list in reverse order (LIFO). Each task invokes the unregister callback. The isEnabled supplier then returns false (since the registry is shut down), and isRegistered() returns false.

In all cases, the unregister callback runs at most once, preventing double-removal.

Known Subclasses

Section titled “Known Subclasses”
ClassPackageAdditional Context
EventRegistrationcom.hypixel.hytale.eventCarries the event class this registration listens to
CommandRegistrationcom.hypixel.hytale.server.core.command.systemHolds the AbstractCommand instance that was registered

These subclasses inherit the lifecycle behavior from Registration and add domain-specific fields.

Usage Example

Section titled “Usage Example”
@Override
protected void setup() {
    // Store the handle to optionally unregister later
    EventRegistration<Void, BootEvent> bootReg =
        getEventRegistry().register(BootEvent.class, event -> {
            getLogger().info("Server booted!");
        });


    // Check if still active
    if (bootReg.isRegistered()) {
        getLogger().info("Boot listener is registered.");
    }


    // Manually unregister (optional -- auto-cleaned on shutdown)
    bootReg.unregister();


    // Now returns false
    assert !bootReg.isRegistered();


    // Safe to call again -- no-op
    bootReg.unregister();
}
Section titled “Related Types”