Rob Harrop and Shaun Smith gave an overview about Oracle Toplinks successor EclipseLink. They started by outlining the problems Rob faced when trying to integrate a JPA provider into SpringSource Application Platform. Shaun then gave a brief overview over EclipseLink which definately exceeds ToplinkEssentials functionality I have used before. It seems to abstract data access in a more broad way including access to XML or JCA.
A major point of the bothy guy’s talk was caching. Shaun presented a demo where a listener constantly triggered a query to the database. It of course was only executed once. Further queries hit the cache as expected. The nice thing about EclipseLink then was that a thread updating the data transparently updated the cached value, so that the changes were reflected in the listener without triggering a new query.
Another hot topic of the presentation was the use of query hints to optimize data access. Rob suggested to have two aspects defined - one to register hints on named queries in a certain business method call context and another one looking up the hints to append when executing the named queries. This sounds quite good and i think i will take some time to reiterate this.
The last amazing topic was a transparent implementation of a database state history. With EclipseLink it is or will (I don’t remember exactly) to query database state at a given point in time. Especi