Map XMLTyp Toplink Essentials

Question

hi,
I'm been looking up info for a while now about XMLType. I found out that Toplink Essentials not directly supports XMLType but I managed to get it from the database. When I have got the object as an oracle.xdb.XMLType then I can read it, which is good, but now (when I alter it) i have to store it again. I use this to alter my XMLType:
    public static void main(String[] args) throws Exception{
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("data");
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        WebeMakrArtikel wma = (WebeMakrArtikel) em.find(WebeMakrArtikel.class, 1L);
        String newXmlString = "<newXml></newXml>";
        XMLType xml = wma.getArtikelXml();
        XMLType newXml = XMLType.createXML(xml.getJavaSqlConnection(), newXmlString);
        wma.setArtikelXml(newXml);       
        em.getTransaction().commit();
        em.close();
        emf.close();
    }But then i get this error :
Exception in thread "main" javax.persistence.RollbackException: java.lang.NullPointerException
     at oracle.toplink.essentials.internal.ejb.cmp3.transaction.base.EntityTransactionImpl.commit(EntityTransactionImpl.java:109)
     at oracle.toplink.essentials.internal.ejb.cmp3.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:45)
     at be.roularta.schrijf.Main.main(Main.java:19)
Caused by: java.lang.NullPointerException
     at oracle.sql.Datum.equals(Datum.java:65)
     at oracle.toplink.essentials.mappings.foundation.AbstractDirectMapping.compareObjects(AbstractDirectMapping.java:286)
     at oracle.toplink.essentials.mappings.foundation.AbstractDirectMapping.compareForChange(AbstractDirectMapping.java:219)
     at oracle.toplink.essentials.descriptors.changetracking.DeferredChangeDetectionPolicy.createObjectChangeSetThroughComparison(DeferredChangeDetectionPolicy.java:124)
     at oracle.toplink.essentials.descriptors.changetracking.DeferredChangeDetectionPolicy.createObjectChangeSet(DeferredChangeDetectionPolicy.java:103)
     at oracle.toplink.essentials.descriptors.changetracking.DeferredChangeDetectionPolicy.calculateChanges(DeferredChangeDetectionPolicy.java:81)
     at oracle.toplink.essentials.internal.sessions.UnitOfWorkImpl.calculateChanges(UnitOfWorkImpl.java:476)
     at oracle.toplink.essentials.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1108)
     at oracle.toplink.essentials.internal.ejb.cmp3.base.RepeatableWriteUnitOfWork.commitRootUnitOfWork(RepeatableWriteUnitOfWork.java:82)
     at oracle.toplink.essentials.internal.sessions.UnitOfWorkImpl.commitAndResume(UnitOfWorkImpl.java:842)
     at oracle.toplink.essentials.internal.ejb.cmp3.transaction.base.EntityTransactionImpl.commit(EntityTransactionImpl.java:90)
     ... 2 moreCan anyone help me to store this XMLType back in the database?
Why does XMLType keep the connection anyway?

Answer 1

XMLType is supported by EclipseLink which is replacing TopLink Essentials as the JPA implementation in GlassFish V3 and will be shipped in OracleAS/TopLink 11gR1. In addition to mapping XMLType columns into XML Strings or DOMs in the domain model the support also includes expression support so that
SQLX queries can be generated.
The solution in EclipseLink involves several classes working together to handle all of the reading, writing and querying capabilities so it not easy to point at a single piece of code to solve your problem.
Doug