13.8Transaction bound event

As of Spring 4.2, the listener of an event can be bound to a phase of the transaction. The typical example is to handle the event when the transaction has completed successfully: this allows events to be used with more flexibility when the outcome of the current transaction actually matters to the listener.

Registering a regular event listener is done via the@EventListenerannotation. If you need to bind it to the transaction use@TransactionalEventListener. When you do so, the listener will be bound to the commit phase of the transaction by default.

Let’s take an example to illustrate this concept. Assume that a component publish an order created event and we want to define a listener that should only handle that event once the transaction in which it has been published as committed successfully:

@Component
   public class MyComponent {

       @TransactionalEventListener
       public void handleOrderCreatedEvent(CreationEvent<Order> creationEvent) {
             ...
       }
   }

TheTransactionalEventListenerannotation exposes aphaseattribute that allows to customize to which phase of the transaction the listener should be bound to. The valid phases areBEFORE_COMMIT,AFTER_COMMIT(default),AFTER_ROLLBACKandAFTER_COMPLETIONthat aggregates the transaction completion (be it a commit or a rollback).

If no transaction is running, the listener is not invoked at all since we can’t honor the required semantics. It is however possible to override that behaviour by setting thefallbackExecutionattribute of the annotation totrue.