Class MessageBus

java.lang.Object

dev.ua.theroer.magicutils.messaging.MessageBus

All Implemented Interfaces:

AutoCloseable

public final class MessageBus
extends Object
implements AutoCloseable

Typed cross-server publish/subscribe bus for MagicUtils plugins.

Wraps a pluggable MessageTransport (the default per-platform plugin-messaging transport, or Redis) with a channel-oriented, typed API: subscribe(String, Class, MessageHandler) and publish(Target, String, Object). Payloads are serialized with a shared MessageCodec. The bus applies Target addressing on receipt so routing behaves identically regardless of which transport is in use.

The bus is AutoCloseable and is meant to be registered with a MagicRuntime so it is torn down with the plugin.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	MessageBus.Builder	Builder for MessageBus.

Method Summary

Modifier and Type	Method	Description
void	broadcast(String channel, @Nullable Object payload)	Broadcasts a payload on a channel to every subscriber on the network.
static MessageBus.Builder	builder(MessageSource self, MessageTransport transport)	Creates a bus builder.
void	close()
MessageCodec	codec()	Returns the codec used for payload serialization.
void	hostsPlayer(@Nullable Predicate<UUID> hostsPlayer)	Sets the predicate answering whether this member hosts a given player id.
void	publish(Target target, String channel, @Nullable Object payload)	Publishes a payload on a channel to the given target.
MessageSource	self()	Returns this member's identity.
<T> ListenerSubscription	subscribe(String channel, Class<T> type, MessageHandler<T> handler)	Subscribes a typed handler to a channel.
MessageTransport	transport()	Returns the underlying transport.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

builder

public static MessageBus.Builder builder(MessageSource self,
 MessageTransport transport)

Creates a bus builder.

Parameters:

self - this member's identity

transport - underlying transport

Returns:

builder

self

public MessageSource self()

Returns this member's identity.

Returns:

self source

transport

public MessageTransport transport()

Returns the underlying transport.

Returns:

transport

codec

public MessageCodec codec()

Returns the codec used for payload serialization.

Returns:

message codec

hostsPlayer

public void hostsPlayer(@Nullable
 @Nullable Predicate<UUID> hostsPlayer)

Sets the predicate answering whether this member hosts a given player id.

Used to honour Target.player(UUID) on backends. Ignored on the proxy. May be updated at any time (for example wired to the online-player registry).

Parameters:

hostsPlayer - predicate, or null to disable player-target delivery

publish

public void publish(Target target,
 String channel,
 @Nullable
 @Nullable Object payload)

Publishes a payload on a channel to the given target.

Parameters:

target - addressing hint

channel - logical channel name

payload - payload object (serialized with the shared codec; may be null)

broadcast

public void broadcast(String channel,
 @Nullable
 @Nullable Object payload)

Broadcasts a payload on a channel to every subscriber on the network.

Parameters:

channel - logical channel name

payload - payload object

subscribe

public <T> ListenerSubscription subscribe(String channel,
 Class<T> type,
 MessageHandler<T> handler)

Subscribes a typed handler to a channel.

Type Parameters:

T - payload type

Parameters:

channel - logical channel name

type - payload type

handler - message handler

Returns:

subscription handle; close it to unsubscribe

close

public void close()

Specified by:

close in interface AutoCloseable