Hi David, [EMAIL PROTECTED] wrote:
The PB is a very low level kernel. It does not track states of objects.Can someone explain the WHY behind this code fragment? It's from org.apache.ojb.broker.singlevm.PersistenceBrokerImpl.store(Object). I thought there was a state kept, to determine if it's an insert or new.
This must be done in client code (maybe your own PB client or in a high level object transaction manager like ODMG or JDO).
The Broker is designed in this way to keep it lean and for a clear separation of concerns.
The broker is for basic persistence operations. ODMG and JDO are Object level transaction managers.
If you don't know if an object is new or not you have to find out first. this is checked by (dbAccess.materializeObject(cld, oid) == null).Having to load the object from the database just to write it back out seems very wasteful.
If you do know that an object requires an update only you can use a different PB method store(Object, ObjectModification) do tell OJB to not perform a check, but use either INSERT or UPDATE as signalled by the ObjectModification.
In fact the ODMG and JDO layers use this method as they track the state of persistent instances.
They do things like
broker.store(instance, ObjectModificationDefaultImpl.UPDATE);
to perform an UPDATE without a prior sanity check!
cheers,
Thomas
boolean doInsert = false; // lookup cache or db to see whether object needs insert or update if (dbAccess.materializeObject(cld, oid) == null) { doInsert = true; // now store it: }This message contains information from Equifax Inc. which may be confidential and privileged. If you are not an intended recipient, please refrain from any disclosure, copying, distribution or use of this information and note that such actions are prohibited. If you have received this transmission in error, please notify by e-mail [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
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