package net.dbyrne.hibernate;

import java.util.Date;

import junit.framework.TestCase;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.auction.AuctionItem;
import org.hibernate.auction.Bid;
import org.hibernate.auction.User;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.hsqldb.Server;

public class HibernateTestCase extends TestCase {
   private static Log log = LogFactory.getLog(HibernateTestCase.class);
   protected Configuration conf;
   protected SessionFactory sessionFactory;
   private static Server server;
   private static String SERVER_PROPS = "database.0=mem:test";
   
   private Long auctionItemId ;
   private Integer userId = new Integer(99);
   private String bidId = "someId";
   int bidAmount = 88;
   private Date bidDate = new Date();
   
    protected void setUp() {
        server = new Server();
        server.putPropertiesFromString(SERVER_PROPS);
        server.start();
      conf = new Configuration().configure();
      sessionFactory = conf.buildSessionFactory();
       SchemaExport schemaExport = new SchemaExport(conf);
       schemaExport.create(true, true);
       
       Session session = sessionFactory.openSession();
       
       Transaction trans = session.beginTransaction();
       
       User user = new User();
       user.setMyUserId(userId);
       user.setEmail("dennis@dbyrne.net");
       user.setFirstName("dennis");
       user.setInitial('C');
       user.setLastName("byrne");
       user.setPassword("scooter");
       user.setUserName("CIA-leak");
       
       session.save(user);
       
       trans.commit();

       Transaction trans2 = session.beginTransaction();
       
       AuctionItem ai = new AuctionItem();
       ai.setCondition(4);
       ai.setDescription("desc.");
       ai.setEnds(new Date());
       
       session.save(ai);
       
       trans2.commit();
       
       Transaction trans3 = session.beginTransaction();
       
       Bid bid = new Bid();
       bid.setMyBidId(bidId);
       bid.setItem(ai);
       bid.setBidder(user);
       bid.setDatetime(bidDate);
       bid.setAmount(bidAmount);
       
       ai.setSeller(user);
       ai.setSuccessfulBid(bid);

       session.save(bid);
       trans3.commit();
       
       auctionItemId = ai.getId();
       session.close();
       log.info("finished creating test data");
    }
   
   protected void tearDown() throws Exception {
      sessionFactory.close();
      sessionFactory = null;
      server.stop();
      server = null;
      super.tearDown();
   }

   public void testUpdate(){
      
      Session session = sessionFactory.openSession();
      Transaction tx = session.beginTransaction();
      
      String hql = "FROM User WHERE id = " + userId.toString();
      User user = (User) session.createQuery(hql).uniqueResult();
      hql = "FROM AuctionItem where id = " + auctionItemId.toString();
      AuctionItem ai = (AuctionItem) session.createQuery(hql).uniqueResult();
      
      Bid bid = new Bid();
      bid.setMyBidId(bidId);       // same id
      bid.setBidder(user);         // same user
      bid.setItem(ai);             // same item
      bid.setDatetime(new Date()); // diff date
      bid.setAmount(bidAmount);    // same amount
      
      // session.merge(bid); // no exception
      session.update(bid); // cause java.lang.NullPointerException
      tx.commit();
      session.close();
   }
}

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="org.hibernate.auction">

   <class name="Bid">
      <comment>A bid or "buy now" for an item.</comment>

      <id name="myBidId" type="string">
         <generator class="assigned" />
      </id>

      <!--  <discriminator type="char">
         <column name="isBuyNow">
         <comment>Y if a "buy now", N if a regular bid.</comment>
         </column>
         </discriminator> -->

      <natural-id>
         <many-to-one name="item" />
         <property name="amount" />
      </natural-id>

      <property name="datetime" not-null="true" column="`datetime`" />

      <many-to-one name="bidder" not-null="true" />
      <!--
         <subclass name="BuyNow"
         discriminator-value="Y"/> -->

   </class>

</hibernate-mapping>

java.lang.NullPointerException
   at org.hibernate.event.def.DefaultFlushEntityEventListener.checkNaturalId(DefaultFlushEntityEventListener.java:70)
   at org.hibernate.event.def.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:145)
   at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:97)
   at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:195)
   at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:76)
   at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:26)
   at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:905)
   at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:345)
   at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
   at net.dbyrne.hibernate.HibernateTestCase.testUpdate(Unknown Source)
   at org.eclipse.ant.internal.ui.antsupport.InternalAntRunner.run(InternalAntRunner.java:416)
   at org.eclipse.ant.internal.ui.antsupport.InternalAntRunner.main(InternalAntRunner.java:138)