JPAExtension

JPA

JSR 317: JavaTM Persistence 2.0 (JPA 2.0) is s a POJO persistence API for object/relational mapping. It contains a full object/relational mapping specification supporting the use of Java language metadata annotations (and/or XML descriptors) to define the mapping between Java objects and a relational database.

The definition of persistent entities, relations, interceptors etc. is annotation based (if you do not use the XML descriptors). Only dependent from the standard package javax.persistence . This allows to choose different JPA implementations/providers like:

• OpenJPA
• Hibernate
• EclipseLink

All of them do provide additional rich feature enhancements like PostGIS syntax, compile time entity enhancement, plug-able extensibility etc.

JPAExtension

JPAExtension does provide

• a Scala interface to the base JPA classes EntityManager, EntityMangerFactory, Query etc. to ease their usage
• Transaction scope and query wrapper to mesh better with Scala’s FP
• more type safe interface using Scala’s type system
• externalized query and filter class definition (dedicated XML file)
• Query parameter holder classes for type safe binding

I know that the most challenging thing is to provide working Scala implementations (suitable for Java Reflection API’s expectations). I will try to collect as many examples as possible for the common issues. (If you have one, contact me.)

The JPAExtension is available at Scala-Tools Maven Snapshot Repository
and it will be available at the Snapshot Documentation Site soon.

For now please visit the short blogposts (blog.fakod.eu/tag/jpa/ ) I wrote to get an impression of JPAExtension and Scala entities.

And as usual: Follow me on Twitter

Maven

To use JPAExtension simple put the following dependency in your pom.xml

	</dependencies>
	  <dependency>
	    <groupId>org.scala-libs</groupId>
	    <artifactId>jpaextension</artifactId>
	    <version>0.0.2-SNAPSHOT</version>
	  </dependency>
	</dependencies>

Planned

The JPA Extension should support

• more examples and test-cases
• enhance Filter Classes features (→ JDBCluster:CCFilter )
• Acegi integration
• Domain value check (→ JDBCluster: Domains) using Bean Validation )