From: Jody G. <jga...@re...> - 2004-04-07 18:23:39
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Alvaro Zabala wrote: > h) Is your feature lock model pessimistic? Are you planning to > consideer optimistic locking and conflicts resolution? We are working > to integrate our DAO model with Hibernate. Hibernate uses optimistic > locking. The FeatureLock model follows the WFS spec, which is pessimistic and the locks only valid for a duration. Actually it supports two styles of locking - locks that are valid for the duration of a transaction, and FeatureLocks that are valid for a duration. Client keeps an authroization ticket which is used to access the locked in the furture. Ticket must be supplied to the Transaction to allow access, Transaction only keeps the ticket for the duration of a commit/rollback. We could extend the API to support optimistic locking - we would need to think up a design. In a perfect world I would like to keep the locking stratagy orthogonal to the DataStores in a manner similar to Transaction. A given DataStore could provide native support as suited. It does get messy though as the FeatureSources (remember there high level optimizations?) can often make use of native locking. This usually avoids walk through the data checking feature Ids before issuing a SQL statement. |