com.interface21.orm.hibernate
Interface HibernateCallback


public interface HibernateCallback

Callback interface for Hibernate code. To be used with HibernateTemplate's execute method, assumably often as anonymous classes within a method implementation. The typical implementation will call Session.load/find/save/update to perform some operations on persistent objects. It can also perform direct JDBC operations via Hibernate's Session.connection() method, returning the active JDBC connection.

Note that Hibernate works on unmodified plain Java objects, performing dirty detection via copies made at load time. Returned objects can thus be used outside of an active Hibernate Session without any hassle, e.g. for display in a web GUI. Reassociating such instances with a new Session, e.g. for updates when coming back from the GUI, is straightforward, as the instance has kept its identity. You should care to reassociate them as early as possible though, to avoid having already loaded a version from the database in the same Session.

Since:
02.05.2003
Author:
Juergen Hoeller
See Also:
HibernateTemplate

Method Summary
 java.lang.Object doInHibernate(net.sf.hibernate.Session session)
          Gets called by HibernateTemplate.execute with an active Hibernate Session.
 

Method Detail

doInHibernate

public java.lang.Object doInHibernate(net.sf.hibernate.Session session)
                               throws net.sf.hibernate.HibernateException,
                                      java.lang.RuntimeException
Gets called by HibernateTemplate.execute with an active Hibernate Session. Does not need to care about activating or closing the Session, or handling transactions.

If called without a thread-bound Hibernate transaction (initiated by HibernateTransactionManager), the code will simply get executed on the underlying JDBC connection with its transactional semantics. If Hibernate is configured to use a JTA-aware DataSource, the JDBC connection and thus the callback code will be transactional if a JTA transaction is active.

Allows for returning a result object created within the callback, i.e. a business object or a collection of business objects. Note that there's special support for List results: see HibernateTemplate.executeFind. A thrown RuntimeException is treated as application exception, it gets propagated to the caller of the template.

Parameters:
session - active Hibernate session
Returns:
a result object, or null if none
Throws:
net.sf.hibernate.HibernateException - in case of Hibernate errors
java.lang.RuntimeException - in case of an application exception, propagating the exception to the caller
See Also:
HibernateTemplate.execute(com.interface21.orm.hibernate.HibernateCallback), HibernateTemplate.executeFind(com.interface21.orm.hibernate.HibernateCallback), HibernateTransactionManager


Rod Johnson and Spring contributors 2001-2003.