Data Access - Spring Enterprise Recipes: A Problem Solution Approach - page 147

http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd" >
...
<tx:annotation-driven />

<bean id="transactionManager"
class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

<bean id="jpaTemplate"
class="org.springframework.orm.jpa.JpaTemplate">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

<bean name="courseDao"
class="com.apress.springenterpriserecipes.course.jpa.JpaCourseDao">
<property name="jpaTemplate" ref="jpaTemplate" />
</bean>
</beans>

Another advantage of HibernateTemplate and JpaTemplate is that they will translate
native Hibernate and JPA exceptions into exceptions in Spring's DataAccessException hierarchy.
This allows consistent exception handling for all the data access strategies in Spring. For
instance, if a database constraint is violated when persisting an object, Hibernate will
throw an org.hibernate.exception.ConstraintViolationException while JPA will throw a
javax.persistence.EntityExistsException . These exceptions will be translated by HibernateTemplate
and JpaTemplate into DataIntegrityViolationException , which is a subclass of Spring's
DataAccessException .
If you want to get access to the underlying Hibernate session or JPA entity manager in
HibernateTemplate or JpaTemplate in order to perform native Hibernate or JPA operations, you
can implement the HibernateCallback or JpaCallback interface and pass its instance to the execute()
method of the template. This will give you a chance to use any implementation-specific features directly
if there's not sufficient support already available from the template implementations.

hibernateTemplate.execute(new HibernateCallback() {
public Object doInHibernate(Session session) throws HibernateException,
SQLException {
// ... anything you can imagine doing can be done here. ➥

Cache invalidation, for example…
}
};

jpaTemplate.execute(new JpaCallback() {
public Object doInJpa(EntityManager em) throws PersistenceException {
// ... anything you can imagine doing can be done here. }
};

Extending the Hibernate and JPA DAO Support Classes
Your Hibernate DAO can extend HibernateDaoSupport to have the setSessionFactory() and
setHibernateTemplate() methods inherited. Then, in your DAO methods, you can simply call
the getHibernateTemplate() method to retrieve the template instance.