How Hibernate SessionFactory autowired using LocalSessionFactoryBean?

Question

Autowiring is happening perfectly and everything works fine. But i need to know how session factory is injected in HibernateTransactionManager using LocalSessionFactoryBean though no relation between LocalSessionFactoryBean class and SessionFactory interface.

PFB the code i used in my project

<beans:bean id="transactionManager"
        class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <beans:property name="sessionFactory"
            ref="localSessionFactoryBean" />
    </beans:bean>
<beans:bean id="localSessionFactoryBean"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <beans:property name="dataSource" ref="dataSource" />
                <beans:property name="hibernateProperties">
            <beans:props>
                <beans:prop key="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect
                </beans:prop>
                <beans:prop key="hibernate.show_sql">true</beans:prop>
            </beans:props>
        </beans:property>
    </beans:bean>

In the above code, I am injecting LocalSessionFactoryBean for sessionFactory in HibernateTransactionManager.

Please, explain how sessionFactory is initialized in HibernateTransactionManager from LocalSessionFactoryBean using annotation driven in detail.

Answer 1

LocalSessionFactoryBean implements FactoryBean<SessionFactory>. So when Spring sets sessionFactory to the HibernateTransactionManager it calls getObject() methods of LocalSessionFactoryBean and gets SessionFactory.

public class LocalSessionFactoryBean extends HibernateExceptionTranslator
        implements FactoryBean<SessionFactory> {

    public SessionFactory getObject() {
        return this.sessionFactory;
    }

}

What's a FactoryBean?