Entity locking question

When an entity has a @Version property, is it automatically version checked on flush/commit or lock() must be called in order for it to get this behaviour ?

Im talking in general, cos i am doing an API to be called from both standalone and server environment.
What should I do here ?
Please tell me the general rule..

Similar Messages

  • CAF Entity locking HELP

    hello
    I am doing some tests in WebDynpro and CAF Core services.
    I have a piece of code as below that retrieves an entity from CAF Core for update. I need this entity to be locked during the update but the two methods lock() and unlock() do nothing. I can still access for update the same entity instance from another user.
    This probably works if the transaction is happening within CAF service but I also need to lock entities from webdynpro when doing complex updates. In other words I am not willing to create a custom method in CAF service for each update I need to implement in webdynpro.
    Any advice ? How are we supposed to use the class com.sap.tc.col.client.generic.api.LockStrategy ? I did not find much about this api.
    Thanks in advance
    Vitaliano
      public void UpdateKAMInTransaction( )
        //@@begin UpdateKAMInTransaction()
         IServiceFacade serviceFacade = CAFServiceFactory.getServiceFacade(cplxmdlDefinition.class);
        String guid = wdContext.currentAKamElement().getGuid();
         AKam akam = MyAppProxy.readKam(guid);
         //locking is not working at all. concurrent changes are lost
         akam.lock(LockStrategy.EXCLUSIVE);
         //update a value here
         akam.setVersion(akam.getVersion() + 1);
         akam.getAspect().sendChanges();
         serviceFacade.save();
         //locking is not working at all. concurrent changes are lost
         akam.unlock();
         wdThis.wdGetAPI().getMessageManager().reportSuccess("done update AKAM=" + akam);
        //@@end

    Now I feel lost. Please keep helping a newby.
    I have implemented my custom method in CAF Services. Here I lock the entity, make all my chanegs, then update and return. I call this custom CAF Application Service method from WebDynpro.
    Nevertheless I noticed that concurrency can still happen. If more than one user updates the same entity at the same time, and exception is thrown in the log files but no exception is thrown. I.e. I cannot intercept the collision.
    in the log file a huge stacktrace is written, while the most interesting message is "javax.jdo.JDOUserException: optimistic transaction failed".
    So... what am I doing wrong here? Should'nt new locking just hold until the existing one is released?
    HELP!
    Vitaliano
         public java.lang.String myUpdateKam(java.lang.String guid, long newVersion) throws com.sap.caf.rt.exception.ServiceException
              // logging
              java.lang.String CAF_user = sessionContext.getCallerPrincipal().getName();
              java.lang.String CAF_methodHeader = MyAppBean.JARM_REQUEST + ":" + "myUpdateKam(java.lang.String, long)";
              Object[] CAF_parameters = new Object[] { guid, new java.lang.Long(newVersion)};
              com.sap.caf.rt.util.CAFPublicLogger.entering(CAF_user, MyAppBean.JARM_REQUEST, CAF_methodHeader, MyAppBean.location, CAF_parameters);
              java.lang.String retValue;
              try
                   //@@custom code start - myUpdateKam(java.lang.String, long)
                   //Read the BO and prepare for changes
                   retValue = "";
                   Kam kam = getKamService().read(guid);
                   char modeLock = IBusinessEntityService.MODE_WRITE;
                   try
                        //Lock BO before updating
                        try
                             getKamService().lock(kam.getKey(), modeLock, 3000);
                             retValue += "-lock-";
                        catch (CAFLockException e)
                             retValue += e.getMessage();
                        //Now do the update and commit
                        // =====> NOTE: regardelss if there is another update in progress,
                        // a concurrent update still gets down to here. WHY ?
                        long counter = kam.getVersion();
                        kam.setVersion(++counter);
                        getKamService().update(kam);
                        retValue += "-update-";
                   catch (CAFUpdateException e)
                        //This case is when concurrent update occurs
                        retValue += e.getMessage();
                   catch (Exception e)
                        //any other exception thrown?
                        retValue += e.getMessage();
                   finally
                        //Make sure we always leave our BO unlocked
                        try
                             getKamService().unlock(kam.getKey(), modeLock);
                             retValue += "-unlock-";
                        catch (CAFLockException e)
                             retValue += e.getMessage();
                   //@@custom code end - myUpdateKam(java.lang.String, long)
                   return retValue;
              finally
                   com.sap.caf.rt.util.CAFPublicLogger.exiting(CAF_user, MyAppBean.JARM_REQUEST, CAF_methodHeader, MyAppBean.location, CAF_parameters);
    This is the code in WebDynpro to invoke CAF custom method.
      public void UpdateKAMRemotely( )
        //@@begin UpdateKAMRemotely()
         IServiceFacade serviceFacade = CAFServiceFactory.getServiceFacade(cplxmdlDefinition.class);
         IAspect retValue = null;
         for (int i = 1; i < 101; i++)
              long newLong = wdContext.currentAKamElement().getVersion() +i;
              retValue = MyAppProxy.myUpdateKam(wdContext.currentAKamElement().getGuid(),newLong);
              IAspectRow row = retValue.getAspectRow(0);
              String retMsg = row.getAttributeAsString("value");
              wdThis.wdGetAPI().getMessageManager().reportSuccess("IAspectRow=" + row + "index="+i);
              serviceFacade.save();
        //@@end
    Message was edited by:
            Vitaliano Trecca

  • About session abnormal termination, table locked question.

    Hi all,
    i test some table lock,after i run this statement:
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    i checked some document, the parameter of SQLNET.EXPIRE_TIME = 5 in sqlnet.ora file can release that lock, i set with 5,and then test again, but still wait 20 minutes the lock can release, why?

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    Hello,
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    The docs are rather specific that all of the functionality for FileLock is platform dependent.
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    Dear all
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    wangjw wrote:
    Dear all
    I have a question about <<Developer’s Guide>> Explicit Locking (27-3)：
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    Hi there. I have a question surrounding the following code block:
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    thank you as always mr. verdagen!
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  • Record Locking question

    Hi,
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    Thanks for the reply.
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  • Lifecycle designer 8 Field Locking question

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    Hi all,
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    Marvin

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