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Application events & lifecycle

ligero-core includes a tiny in-process event bus and lifecycle hooks so producers and consumers decouple without a message broker.

Install with the CLI
ligero add events

Events and the lifecycle hooks are in ligero-core — no extra dependency.

Events​

Events events = new Events();

// subscribe by type (also delivered to supertype/interface subscribers)
events.subscribe(OrderPlaced.class, e -> mailer.confirm(e.orderId()));
events.subscribe(DomainEvent.class, e -> audit.record(e));

// publish anywhere you hold the bus
events.publish(new OrderPlaced(42));
  • Delivery is synchronous and in subscription order.
  • A subscriber matches the event's exact type and any supertype/interface it implements.
  • A handler that throws is logged and does not stop the others.

Register the Events bus as a bean and inject it where you publish or subscribe.

Lifecycle hooks​

Run code when the server starts (port bound) and stops (before the engine shuts down):

app.onStart(() -> log.info("ready on {}", app.port()))
   .onStop(scheduler::close)
   .onStop(pool::close);
app.start();

Hooks run in registration order; a failing hook is logged and doesn't abort the rest.

Notes​

  • Use events for in-process decoupling (a write triggers a notification, an audit entry, a cache invalidation). For cross-service messaging, publish to a broker from a subscriber.
  • Lifecycle hooks are the clean place to start/stop a Scheduler, close a connection pool, or warm a cache.