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From Christopher Schmidt <>
Subject Re: JPA and Scala
Date Mon, 24 May 2010 09:15:03 GMT
John, I am not sure if I understand you right... (JPAExtension is not
a application, it is a library)

5 years ago we started to use a really complex relational schema (that
uses really every relational modeling feature available regarding
primary keys and subclassing). We used Hibernate (non JPA) for access,
AspectJ (for transaction and rights handling) and Sun's Jersey (JAX-RS
implementation) to deploy it (in a Tomcat) as several webservices.

This year we started to switch to JPA 2.0 (and OpenJPA. Bender1199
posted already some questions here or to the user list) as persistence
layer. Next step was to think about using Scala as "backend language"
and therefore we started to use it together with OpenJPA. The first
thing what came out was wrapping EntitiyManager, EntityManagerFacory
and Query (to make it more type safe). The filter-object concept was
to simplify the query parameter handling (and make it more typesafe
again). The result is the JPAExtension - thats all.

The "Server Side Example" in my blog came from a small geo tagging
project (mainly a test for replacing Aspects by Scala's functional

Hope thats what you wanted to know...


On Sun, May 23, 2010 at 1:30 PM, Web developer <> wrote:
> Who will use your application? What process it automates? John
> 2010/5/22 Christopher Schmidt <>
>> Just to be sure: what do you mean with practical purpose?
>> Christopher
>> Am 22.05.2010 13:49 schrieb "Web developer" <>:
>> Interesting, and what is a practical purpose of application(s) that you
>> develop? John
>> 2010/5/21 Christopher Schmidt <>
>> > Hi all,
>> > I am working on a JPA wrapper for Scala and I think that I have found
>> > an elegant way ...

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