Differences between session.lock and query.setLockMode.

Marcos Silva Pereira · **Posted:** Mon Nov 27, 2006 6:22 pm

Hibernate version: 3.1.3
Mapping documents: not matter
Name and version of the database you are using: PostgreSQL 8.1.3

Hello, I have implemented some classes to translate hibernate exceptions and other stuff and now I have some doubt about lock methods to use pessimistic locking. So, I have done the following code:

Code:

public List findUnique(String query, Object[] params, String lockAlias) {

   Session session = (Session) transManag.getPersistenceSession();

   String queryValue = queryProperties.getProperty(query);
   Type[] types = TypeConverter.convertTypes(params);

   Query hibernateQuery = session.createQuery(queryValue);
   hibernateQuery.setParameters(params, types);
   hibernateQuery.setMaxResults(1);

   return hibernateQuery.setLockMode(lockAlias, LockMode.WRITE).list();
}

But this is a little bit intrusive because I must specify the lockAlias. Therefore, I am considering change it to the code below:

Code:

public List findUnique(String query, Object[] params) {

   Session session = (Session) transManag.getPersistenceSession();

   String queryValue = queryProperties.getProperty(query);
   Type[] types = TypeConverter.convertTypes(params);

   Query hibernateQuery = session.createQuery(queryValue);
   hibernateQuery.setParameters(params, types);
   hibernateQuery.setMaxResults(1);

   List queryResult = hibernateQuery.setLockMode(lockAlias, LockMode.WRITE).list();

   Object result = queryResult.iterator().next();

   return result;
}

In the second code snipped I don't have to use the alias parameter. But I am concerned about concurrency issues. Is the first way more secure than the second? Or are they equivalent?

kind regards