Creating a post commit when using transaction in Spring

Question

Due to certain reasons i have manually performed transaction commit and roll back using Spring PlatformTransactionManager, what i need to do is setup a hook so that a post c

Answer 1

Since Spring 4.2 it has been possible to define listeners for post commit events (or more generally transaction synchronization events e.g. rollbacks) using annotation based configuraton. This is based off event handling in core spring. It is easier to test code using this approach since you avoid a direct dependency on TransactionSynchronizationManager, which will likely not be active in a unit test. You can easily test that your transactional service publishes an event and also that your listener performs the right action when you receive an event.

So without further ado this is how to set it up:

In this example we'll assume you have a Customer entity and a CustomerRepository (and ORM to go with it).

First you need a new event type NewCustomerEvent:

// NewCustomerEvent.java
// Just a regular pojo for the event
public class NewCustomerEvent {

    public String email;

    // constructor, setters and getters omitted
}

Then you define a listener using @TransactionalEventListener. By default this will execute after a sucessful commit but this can be changed using the phase parameter:

// NewCustomerEventListener.java
@Component
public class NewCustomerEventListener {

    @TransactionalEventListener
    public void handleNewCustomerEvent(NewCustomerEvent newCustomerEvent) {
        // handle new customer event
    }
}

Finally you augment your transaction service with an ApplicationEventPublisher on which you call publish once all the transaction statements have been sent.

// CustomerRespositoryService.java
@Service
public class CustomerRepositoryService {

    @Inject
    private ApplicationEventPublisher applicationEventPublisher;

    @Inject
    private CustomerRepository customerRepository;

    @Transactional
    public void createCustomer(String email) {
        Customer customer = new Customer(email);
        customerRespotory.save(customer);
        applicationEventPublisher.publish(new NewCustomerEvent(email));
    }

}

See also:

• https://dzone.com/articles/simpler-handling-of-asynchronous-transaction-bound
• https://dzone.com/articles/transaction-synchronization-and-spring-application