Re: Optimistic Locking

[Armin Waibel]

By the way, I'm using CVS head

ClassDescriptor#updateLockingValues(Object obj)
increment version field on object
regards,
Armin
[EMAIL PROTECTED] wrote:

I've looked through the OJB source code and can't find where it is 
incrementing the version number before an update.  Can you please tell me 
where that happens?

Thanks
Jay
On Thu, 26 Feb 2004, Armin Waibel wrote:


Hi Jay,

mapping seems ok, so it's difficult to say what's going wrong. You can 
use p6spy to log the generated SQL statements, maybe this will sheed 
some light on it.
(Or set DEBUG log level for 
org.apache.ojb.broker.accesslayer.sql.SqlGeneratorDefaultImpl
to see the generated prepared SQL statements without values).

In OJB test suite you can find a test case for optimistic locking called 
...broker.OptimisticLockingTest (all tests pass).

regards,
Armin
[EMAIL PROTECTED] wrote:


Hello, I can't figure out how Optimistic locking should work.  I followed 
the instructions in the FAQ but it doesn't work.  This is the only 
documentation I have found about Optimistic locking.  Can someone help?  
Here is how I have things configured.

I'm using rc4.

Here's my table in the repository.xml file:

<class-descriptor class="edu.iu.uis.ps.data.ApplicationSettingsBean" 
table="PS_APPL_STTG_T">
 <field-descriptor name="appSettingName" column="APPL_STTG_NM" 
jdbc-type="VARCHAR" primarykey="true" />
 <field-descriptor name="appSettingText" column="APPL_STTG_TXT" 
jdbc-type="VARCHAR" />
 <field-descriptor name="ojbVerNbr" column="OJB_VER_NBR" 
jdbc-type="BIGINT" locking="true"/>
</class-descriptor>

(note the locking="true" on ojbVerNbr)

The table doesn't allow null values in ojb_ver_nbr.  If I try to insert a 
row and don't set ojb_ver_nbr, I get an exception because ojb_ver_nbr 
isn't set.

If I try to simulate a situation where optimistic locking is necessary, it 
doesn't work.  The value of ojb_ver_nbr never changes and it doesn't 
detect situations that it should.  Here is sample code:

   ApplicationSettingsBean as = new ApplicationSettingsBean();
   as.setAppSettingName("junk");
   as.setAppSettingText("Value 1");
   as.setOjbVerNbr(new Long(1));
   as.store(broker);
   System.err.println("Stored");
   ApplicationSettingsBean as1 = new ApplicationSettingsBean();
   as1.setAppSettingName("junk");
   as1.setAppSettingText("Value 2");
   as1.setOjbVerNbr(new Long(1));
   ApplicationSettingsBean as2 = new ApplicationSettingsBean();
   as2.setAppSettingName("junk");
   as2.setAppSettingText("Value 3");
   as2.setOjbVerNbr(new Long(1));
   as1.store();
   System.err.println("2nd Stored");
   // This should fail
   as2.store();
   System.err.println("3rd Stored");
The 3rd store should fail because it tried to write on top of the 2nd 
store.  It succeeds and the ojb_ver_nbr column never changes.

Can someone please tell me how to get this to work?

Thanks
Jay


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