Logging using Interceptors

One of the most popular uses of Interceptors is to log object creations/insertions and deletions. Interceptors allow you to transparently log these state changes and manage the audit trail for an entity.

Testing the Interceptor

In the previous post we created a simple Interceptor that logged different operations to the console when they occurred. For testing I created an Entity class that has a one-to-one relation and a collection and decided to test out various operations on it.

Spring and Events and Listeners

Spring's ApplicationContext provides the functionality to support events and listeners in code. Spring allows us to create listeners in the code. We can create beans that listen for events which are published through our ApplicationContext. This is achieved via the ApplicationEventPublisher interface.

Hibernate Queries and the Question Mark

The one thing we see in logs when we use Hibernate is the Question Mark. The question mark makes its appearance in all queries generated whether you use HQL or Criteria or do a load on the object identifier. If we need to debug a query, we need to actually copy the values from bind parameters and then replace them for the question marks. This (and I am sure developers will agree with me ) is a pain. Real PAIN.

Listeners in Hibernate

Hibernate 3.x is built on the concept of events and listeners.To deal with the different operations like loading an object, saving an object, Hibernate creates events. There exists listeners in the Hibernate framework listening for these events.