Hibernate version:
3.2

I used hbm2dao to generate my DAO PersonHome.java, and I assume the following method is to create/persist a new Person into the database:



However, I get the following exception:



I understand (from the example) that you should call beginTransaction() on the session before calling save(). So how is the persist() method supposed to function in this generated DAO?

Furthermore, is there documentation on what the generated methods in this PersonHome class are supposed to do exactly, such as attachDirty, attachClean, merge?

Thanks.

Use a layer above the DAOs to control the Transaction boundaries. This might be a CMT method or a manually managed transaction boundary. This allows the DAO methods to be called when you please under a what ever transaction is required for the current execution context.

I'm looking for that kind of documentation, too.

Not really but the methods are short and use the hibernate core API which is well documented. Just as the persist DAO method is really a wrapper to Hibernate's session.persist method thus API docs for hibernate has all the information you require.

I am writing a test on a dao using hsqldb:

public class DataDaoTestCase {

private SessionFactory mSessionFactory;
private Session mSession;
private Transaction mTransaction;
private DataDao mDataDao;

protected void setUp() throws Exception {
mSessionFactory = createSessionFactory();
mDataDao = new HibernateDataDao(mSessionFactory);
mSession = mSessionFactory.openSession();
mTransaction = mSession.beginTransaction();
}

public void testPersist() {
...
mDataDao.save(aDataObject);
...
}
}

My HibernateDataDao is:
public class HibernateDataDao implements DataDao {
private SessionFactory mSessionFactory;
public HibernateDataDao(SessionFactory aSessionFactory) {
mSessionFactory = aSessionFactory;
}
public Long save(DataObject aDataObject) {
return (Long) mSessionFactory
.getCurrentSession().save(aDataObject);
}
}

But I still get this exception:
org.hibernate.HibernateException: save is not valid without active transaction
at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:297)
at $Proxy8.save(Unknown Source)
at HibernateDataDao.save(HibernateDataDao.java:93)
at HibernateDataDaoTestCase.testSave(HibernateDataDaoTestCase.java:122)

My hibernate.cfg.xml is:
<hibernate-configuration>
<session-factory>
<property name="connection.driver_class">org.hsqldb.jdbcDriver</property>
<property name="connection.url">jdbc:hsqldb:mem:aname</property>
<property name="connection.username">sa</property>
<property name="connection.password"></property>
<property name="hibernate.dialect">org.hibernate.dialect.HSQLDialect</property>
<property name="hibernate.current_session_context_class">thread</property>
<property name="hibernate.cache.use_second_level_cache">true</property>
<property name="hibernate.cache.use_query_cache">true</property>
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>

<property name="show_sql">true</property>
<property name="format_sql">true</property>

<property name="hibernate.hbm2ddl.auto">create</property>
</session-factory>
</hibernate-configuration>

Mapping resources are added in createSessionFactory() method.

In the setUp() of the test class, instead of using:
mSession = mSessionFactory.openSession();
mTransaction = mSession.beginTransaction();

use:
mSession = mSessionFactory.getCurrentSession();
mTransaction = mSession.beginTransaction();

My understanding is that:
getCurrentSession() will create a new session if there is none bound to the thread context, while openSession() does not bound the new session to the thread context.

You are correct getCurrentSession() is the recommended approach as it helps you control the tx/session context for free.