OpenJPA
  1. OpenJPA
  2. OPENJPA-1645

Instance not found when using inheritance and hierarchy is higher than 2

    Details

    • Type: Bug Bug
    • Status: Open
    • Priority: Major Major
    • Resolution: Unresolved
    • Affects Version/s: 2.0.0
    • Fix Version/s: None
    • Component/s: None
    • Environment:

      Description

      Assume the following class hierarchy: A super class of B superclass of C using single table strategy.

      Case 1:
      1a: Create and persist instance of B (e.g. primary key = 1)
      1b: Find instance via entity manager find like em.find(B.class, 1) → this works as expected
      1c: Find instance via entity manager find like em.find(A.class, 1) → this works as expected

      Case 2:
      2a: Create and persist instance of C (e.g. primary key = 2)
      2b: Find instance via entity manager find like em.find(C.class, 2) → this works as expected
      2c: Find instance via entity manager find like em.find(A.class, 2) → this works as expected
      2d: Find instance via entity manager find like em.find(B.class, 2) → instance is not found

      The reason is as follows (only part of the code is shown to make this shorter)

      // TestA is like
      @Entity
      @Inheritance
      @DiscriminatorColumn(name = "dis", discriminatorType = DiscriminatorType.STRING)
      public abstract class TestA implements Serializable {

      private static final long serialVersionUID = -4733743965438652043L;

      // id
      @Id
      private long id;

      private String name;

      public TestA() {
      }

      public TestA(String name)

      { id = System.nanoTime(); this.name = name; }

      // TestsB is like
      @Entity
      public class TestB extends TestA {

      private static final long serialVersionUID = -2091733862251849317L;

      // Constructors
      public TestB()

      { super(); }

      public TestB(String name) { super(name); }

      // TestC is like
      @Entity
      public class TestC extends TestB {

      private static final long serialVersionUID = -2091733862251849317L;

      // Constructors
      public TestC() { super(); }

      public TestC(String name)

      { super(name); }

      The facade looks like this:
      @Override
      public void create(TestA test)

      { em.persist(test); }

      @Override
      public <T extends TestA> T find(Class<T> cls, long id)

      { return em.find(cls, id); }

      // Somewhere in a bean ...
      @EJB
      private TestFacadeLocal tf;

      // ...

      // *** Case 1 ***

      // Case 1a
      TestB tb0 = new TestB("name1");
      tf.create(tb0);

      // Case 1b
      tb0 = tf.find(TestB.class, tb0.getId());

      Resulting SQL:
      SELECT t0.dis, t0.name FROM TestA t0 WHERE t0.dis = ? AND t0.id = ? [params=(String) TestB, (long) 4013390270882]

      The discriminator column is taken into account, this is ok

      // Case 1c
      TestA ta0 = tf.find(TestA.class, tb0.getId());

      Resulting SQL:
      SELECT t0.dis, t0.name FROM TestA t0 WHERE t0.id = ? [params=(long) 4013390270882]

      The discriminator column is not taken into account to be able to retrieve TestA. This is ok.

      // *** Case 2 ***

      // Case 2a
      TestC tc1 = new TestC("name1");
      tf.create(tc1);

      // Case 2b
      tc1 = tf.find(TestC.class, tc1.getId());

      Resulting SQL:
      SELECT t0.dis, t0.name FROM TestA t0 WHERE t0.dis = ? AND t0.id = ? [params=(String) TestC, (long) 4013797794600]

      The discriminator column is taken into account. This is ok

      // Case 2c
      TestA ta1 = tf.find(TestA.class, tc1.getId());

      Resulting SQL:
      SELECT t0.dis, t0.name FROM TestA t0 WHERE t0.id = ? [params=(long) 4013797794600]

      The discriminator column is not taken into account to be able to retrieve TestA. This is ok.

      // Case 2d
      TestB tb1 = tf.find(TestB.class, tc1.getId());

      Resulting SQL:
      SELECT t0.dis, t0.name FROM TestA t0 WHERE t0.dis = ? AND t0.id = ? [params=(String) TestB, (long) 4013797794600]

      Here the problem arises. The discriminator column is taken in the wrong way into account. It just checks for "TestB" but it should also take "TestC" into account. The result is, that the instance is not found. Actually the same scenario works fine with SNAPSHOT 1.3.0.

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          • Assignee:
            Unassigned
            Reporter:
            Georg Nozicka
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            Dates

            • Created:
              Updated:

              Development