[OJB-developers] Optimistic locking

[Jakob B. <jbr...@ho...>]

hi,

the attached zip contains some code based on version 0.7.310 to support
optimistic locking for int, long and timestamp fields.

<FieldDescriptor id="6">
<field.name>test</field.name>
<column.name>test</column.name>
<jdbc_type>INTEGER</jdbc_type>
<locking>true</locking>
</FieldDescriptor>
<FieldDescriptor id="8">
<field.name>lastModified</field.name>
<column.name>entryDate</column.name>
<jdbc_type>TIMESTAMP</jdbc_type>
<locking>true</locking>
</FieldDescriptor>

the locking fields are used in the where-clause for update and delete. if
the rowcount of the update is 0, an exception is thrown
(JdbcAccess::executeUpdate()) :
...
broker.getStatementManager().bindUpdate(stmt, mif, obj);
if (stmt.executeUpdate() == 0 && mif.isLocking()) //BRJ
{
    throw new PersistenceBrokerException("Object has been modified by
someone else");
}
...

hth
jakob