[infinispan-dev] Query API, JPA and a fine-grained model

So the plan is that we would implement a new fine-grained model to replace POJO Cache. Rather than AOP, we would use a JPA-like session- style interface where we can track changes made to state in a session to detect field changes [1]. This hugely simplifies the implementation and makes things more robust, plus provides people with a familiar JPA API to use. Now considering the query API, if we are already providing a JPA interface, this is another reason for the query API to support JPA-QL rather than just Lucene queries. The other reason, of course, is easy migration off using databases for persistence to using a data grid for persistence [2]. Now, naturally, the designs outlined in [2] can easily be achieved using Hibernate and a good distributed cache, but what happens when you don't actually want to persist your data at all, just want it to live in a grid (because you think your grid is "good enough" to not be unavailable, and/or your data is transient or can be recalculated), but you still want to use a JPA interface because either you are more familiar with it, or you started off storing this state in JPA and are now rethinking your persistence needs but don't want to rewrite your app. Of course, supporting JPA-QL in a distributed cache query API is not trivial. We know we can do this fairly easily with Lucene queries. Does anyone know of a mechanism to translate between these easily enough? If need be, this is something we could build. JPA-QL grammar is finite and an ANTLR [3] definition to translate these to Lucene query objects shouldn't be too hard ... Thoughts? Manik [1] http://www.jboss.org/community/wiki/NewFineGrainedReplicationAPIDesign [2] http://web2.sys-con.com/node/951117 [3] http://www.antlr.org/ -- Manik Surtani manik(a)jboss.org Lead, Infinispan Lead, JBoss Cache http://www.infinispan.org http://www.jbosscache.org