publishEvent abstract method

Publishes the given event to all registered ApplicationEventListeners.

This method implements the Observer pattern within the application context, allowing decoupled communication between application components.

Event Delivery Guarantees:

• Synchronous Delivery: Events are typically delivered synchronously
• Order Preservation: Events are delivered in publication order
• Exception Handling: Listener exceptions are caught and logged
• Thread Context: Events are published in the caller's thread context

Event Types:

• Context Lifecycle Events: ContextRefreshedEvent, ContextClosedEvent
• Application Domain Events: UserCreatedEvent, OrderProcessedEvent
• Framework Events: Internal framework operation events

Example:

class OrderService {
  final ApplicationContext context;
  
  OrderService(this.context);
  
  Future<Order> createOrder(OrderRequest request) async {
    final order = Order.fromRequest(request);
    
    // Persist order
    await orderRepository.save(order);
    
    // Publish domain event
    context.publishEvent(OrderCreatedEvent(this, order));
    
    return order;
  }
}

class OrderEventListener implements ApplicationEventListener<OrderCreatedEvent> {
  @override
  void onApplicationEvent(OrderCreatedEvent event) {
    // Send confirmation email
    emailService.sendConfirmation(event.order);
    
    // Update inventory
    inventoryService.reserveItems(event.order.items);
  }
}

Error Handling:

If a listener throws an exception, it is caught and logged, but other listeners will still receive the event. The publishing code is not affected by listener exceptions.