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From Rick Curtis <curti...@gmail.com>
Subject Re: my fist openjpa porject / problem. help me please
Date Wed, 20 Feb 2013 02:34:35 GMT
What is at com.caf.db.dao.JpaDao.persist(JpaDao.java:20)?


On Tue, Feb 19, 2013 at 5:08 PM, Aitor Iturriondobeitia <
laudio.info@gmail.com> wrote:

> hello
> i an tring to build my firts openjpa app
> i am readint this article (
> http://java.dzone.com/articles/jpa-implementation-patterns) and building
> it
> for this i make this:
> 1.- generic interface:
> public interface IGenericDao<K, E> {
>  void persist(E entity);
> }
> 2.- other interface, my interface.
> public interface IWsSrvTrackRequest  extends IGenericDao<Integer,
> Wssrvtrackrequest>{
>  void wsSrvRequestPersist(Wssrvtrackrequest request);
> }
> 3.- generic JPA-DAO:
> public abstract class JpaDao<K, E> implements IGenericDao<K, E> {
>  protected Class<E> entityClass;
>
>  @PersistenceContext
>  protected EntityManager entityManager;
>
>  public JpaDao() {
>   ParameterizedType genericSuperclass = (ParameterizedType)
> getClass().getGenericSuperclass();
>   this.entityClass = (Class<E>)
> genericSuperclass.getActualTypeArguments()[1];
>  }
>  public void persist(E entity) {
>   entityManager.persist(entity);
>  }
>  }
> }
> 4.- my jpa-dao implementation (the Wssrvtrackrequest obj is one jpa object
> (entity)).
> public class JpaWsSrvTrackRequestDaoImpl extends JpaDao<Integer,
> Wssrvtrackrequest> implements IWsSrvTrackRequest {
>  public void wsSrvRequestPersist(Wssrvtrackrequest request){
>    entityManager.persist(request);
>  }
> }
> i am make one main class:
> public static void main(String[] args) {
>   IWsSrvTrackRequest r = new JpaWsSrvTrackRequestDaoImpl();
>   Wssrvtrackrequest v = new Wssrvtrackrequest();
>   v.setWssrvreqIp("la ip");
>   v.setWssrvreqOid("oid");
>   v.setWssrvreqOiduser("oiduser");
>   v.setWssrvreqRequest("la request");
>   r.persist(v);
>  }
>
>  but it always returns one nullpointerexception.
>  Exception in thread "main" java.lang.NullPointerException
>  at com.caf.db.dao.JpaDao.persist(JpaDao.java:20)
>  at com.caf.db.dao.ll.main(ll.java:20)
>
>  Can you help me please?
>
>  thanks
>



-- 
*Rick Curtis*

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