ass1-jpa/src/test/java/dst/ass1/jpa/tests/UniqueConstraintTester.java

   1 package dst.ass1.jpa.tests;
   2
   3 import static org.junit.Assert.fail;
   4
   5 import java.util.function.Consumer;
   6 import java.util.function.Supplier;
   7
   8 import javax.persistence.EntityManager;
   9 import javax.persistence.EntityTransaction;
  10 import javax.persistence.PersistenceException;
  11
  12 import org.hibernate.exception.ConstraintViolationException;
  13
  14 /**
  15  * Tests a unique constraint by creating two instances of an entity, calling the same value setter on each entity,
  16  * and finally trying to persist them.
  17  *
  18  * @param <E> the entity type
  19  */
  20 public class UniqueConstraintTester<E> {
  21
  22     private Consumer<E> valueSetter;
  23     private E e1;
  24     private E e2;
  25
  26     public UniqueConstraintTester(E e1, E e2, Consumer<E> valueSetter) {
  27         this.e1 = e1;
  28         this.e2 = e2;
  29         this.valueSetter = valueSetter;
  30     }
  31
  32     public UniqueConstraintTester(Supplier<E> entityFactory, Consumer<E> valueSetter) {
  33         this(entityFactory.get(), entityFactory.get(), valueSetter);
  34     }
  35
  36     public void run(EntityManager em) {
  37         EntityTransaction tx = em.getTransaction();
  38         if (!tx.isActive()) {
  39             tx.begin();
  40         }
  41
  42         valueSetter.accept(e1);
  43         em.persist(e1);
  44         em.flush();
  45
  46         try {
  47             valueSetter.accept(e2);
  48             em.persist(e2);
  49             em.flush();
  50             fail("Missing unique constraint in " + e2.getClass());
  51         } catch (PersistenceException e) {
  52             Throwable cause = e.getCause();
  53             if (!(cause instanceof ConstraintViolationException)) {
  54                 fail("Missing unique constraint in " + e2.getClass());
  55             }
  56         }
  57     }
  58 }