[OJB-developers] mapping inheritance hierarchies question

[Matt G. <mat...@ss...>]

Hello again,

I've been trying to get the "mapping all classes on the same table" scenario
working. I think there's a bug in the code that instantiates these objects.
I originally posted about problems with this in December last year - I
should have followed it up sooner :(.

The easiest way to hilight the problem is by extending the
PersistenceBrokerTest.java unit tests - at the end of the message is a
modified version of the testMappingToOneTable() test.

AFAICT, the test now adds 2 A's and 1 B, I haven't found any other tests
which add any more. I would therefore expect the table to hold 2 A's and 1 B
which should mean that a search for AB's, A's and B's should return 3, 2 and
1 objects respectively. You actually get 6, 3 and 3 objects!

Hopefully, I've understood how to use OJB in this way. If not, my apologies
for saying there's a bug ;)

Hopefully, one day (if I ever get to use OJB properly), I'll be able to send
patches in instead.

Cheers, Matt

----------------------------------------------------------------------
    /**
     * performs a test of the inheritance mapping to one table.
     */
    public void testMappingToOneTable()
    {
        try
        {
            A a1 = new A();
            Identity iA1 = new Identity(a1);

            A a2 = new A();
            Identity iA2 = new Identity(a2);

            B b1 = new B();
            Identity iB2 = new Identity(b1);

            broker.store(a1);
            broker.store(a2);

            broker.store(b1);

   AB ab = null;

            Criteria crit = new Criteria();
            crit.addEqualTo("id", new Integer(a1.id));
            Query q = QueryFactory.newQuery(AB.class, crit);
            ab = (AB) broker.getObjectByQuery(q);

            assertEquals(A.class.getName(), ab.getConcreteClass());
            assertEquals(A.class, ab.getClass());


            crit = new Criteria();
            crit.addEqualTo("id", new Integer(b1.id));
            q = QueryFactory.newQuery(AB.class, crit);
            ab = (AB) broker.getObjectByQuery(q);
            assertEquals(B.class.getName(), ab.getConcreteClass());
            assertEquals(B.class, ab.getClass());

   Collection abs = null;

   // Test retrieval of collections
   q  = QueryFactory.newQuery(AB.class, null);
   abs = broker.getCollectionByQuery(q);
   //System.out.println("AB's = " + abs.size());
   assertEquals(abs.size(), 3);

   q  = QueryFactory.newQuery(A.class, null);
   abs = broker.getCollectionByQuery(q);
   //System.out.println("A's = " + abs.size());
   assertEquals(abs.size(), 2);

   q  = QueryFactory.newQuery(B.class, null);
   abs = broker.getCollectionByQuery(q);
   //System.out.println("B's = " + abs.size());
   assertEquals(abs.size(), 1);
        }
        catch (Throwable t)
        {
            fail(t.getMessage());
        }
    }
----------------------------------------------------------------------

---
Matt Goodall
Analyst Programmer, Strategic Systems Solutions
e: mat...@ss..., t: +44 113 3892645