Examples with ScrollableResults org.hibernate.ScrollableResults used on opensource projects

Example 1 with ScrollableResults

use of org.hibernate.ScrollableResults in project querydsl by querydsl.

the class IntegrationBase method scroll.

@Test
public void scroll() {
    session.save(new Cat("Bob", 10));
    session.save(new Cat("Steve", 11));
    QCat cat = QCat.cat;
    HibernateQuery<?> query = new HibernateQuery<Void>(session);
    ScrollableResults results = query.from(cat).select(cat).scroll(ScrollMode.SCROLL_INSENSITIVE);
    while (results.next()) {
        assertNotNull(results.get(0));
    }
    results.close();
}

Example 2 with ScrollableResults

use of org.hibernate.ScrollableResults in project hibernate-orm by hibernate.

the class HQLTest method test_hql_api_scroll_projection_example.

@Test
public void test_hql_api_scroll_projection_example() {
    doInJPA(this::entityManagerFactory, entityManager -> {
        Session session = entityManager.unwrap(Session.class);
        try (ScrollableResults scrollableResults = session.createQuery("select p " + "from Person p " + "where p.name like :name").setParameter("name", "J%").scroll()) {
            while (scrollableResults.next()) {
                Person person = (Person) scrollableResults.get()[0];
                process(person);
            }
        }
    });
}

Example 3 with ScrollableResults

use of org.hibernate.ScrollableResults in project hibernate-orm by hibernate.

the class BatchTest method withScroll.

private void withScroll() {
    withBatch();
    //tag::batch-session-scroll-example[]
    EntityManager entityManager = null;
    EntityTransaction txn = null;
    ScrollableResults scrollableResults = null;
    try {
        entityManager = entityManagerFactory().createEntityManager();
        txn = entityManager.getTransaction();
        txn.begin();
        int batchSize = 25;
        Session session = entityManager.unwrap(Session.class);
        scrollableResults = session.createQuery("select p from Person p").setCacheMode(CacheMode.IGNORE).scroll(ScrollMode.FORWARD_ONLY);
        int count = 0;
        while (scrollableResults.next()) {
            Person Person = (Person) scrollableResults.get(0);
            processPerson(Person);
            if (++count % batchSize == 0) {
                //flush a batch of updates and release memory:
                entityManager.flush();
                entityManager.clear();
            }
        }
        txn.commit();
    } catch (RuntimeException e) {
        if (txn != null && txn.isActive())
            txn.rollback();
        throw e;
    } finally {
        if (scrollableResults != null) {
            scrollableResults.close();
        }
        if (entityManager != null) {
            entityManager.close();
        }
    }
//end::batch-session-scroll-example[]
}

Example 4 with ScrollableResults

use of org.hibernate.ScrollableResults in project hibernate-orm by hibernate.

the class BatchTest method doBatchInsertUpdate.

public void doBatchInsertUpdate(int nEntities, int nBeforeFlush) {
    Session s = openSession();
    s.setCacheMode(CacheMode.IGNORE);
    Transaction t = s.beginTransaction();
    for (int i = 0; i < nEntities; i++) {
        DataPoint dp = new DataPoint();
        dp.setX(new BigDecimal(i * 0.1d).setScale(19, BigDecimal.ROUND_DOWN));
        dp.setY(new BigDecimal(Math.cos(dp.getX().doubleValue())).setScale(19, BigDecimal.ROUND_DOWN));
        s.save(dp);
        if (i + 1 % nBeforeFlush == 0) {
            s.flush();
            s.clear();
        }
    }
    t.commit();
    s.close();
    s = openSession();
    s.setCacheMode(CacheMode.IGNORE);
    t = s.beginTransaction();
    int i = 0;
    ScrollableResults sr = s.createQuery("from DataPoint dp order by dp.x asc").scroll(ScrollMode.FORWARD_ONLY);
    while (sr.next()) {
        DataPoint dp = (DataPoint) sr.get(0);
        dp.setDescription("done!");
        if (++i % nBeforeFlush == 0) {
            s.flush();
            s.clear();
        }
    }
    t.commit();
    s.close();
    s = openSession();
    s.setCacheMode(CacheMode.IGNORE);
    t = s.beginTransaction();
    i = 0;
    sr = s.createQuery("from DataPoint dp order by dp.x asc").scroll(ScrollMode.FORWARD_ONLY);
    while (sr.next()) {
        DataPoint dp = (DataPoint) sr.get(0);
        s.delete(dp);
        if (++i % nBeforeFlush == 0) {
            s.flush();
            s.clear();
        }
    }
    t.commit();
    s.close();
}

Example 5 with ScrollableResults

use of org.hibernate.ScrollableResults in project hibernate-orm by hibernate.

the class AggressiveReleaseTest method testSerializationFailsOnAfterStatementAggressiveReleaseWithOpenResources.

@Test
public void testSerializationFailsOnAfterStatementAggressiveReleaseWithOpenResources() throws Throwable {
    prepare();
    Session s = getSessionUnderTest();
    Silly silly = new Silly("silly");
    s.save(silly);
    // this should cause the CM to obtain a connection, and then release it
    s.flush();
    // both scroll() and iterate() cause batching to hold on
    // to resources, which should make aggressive-release not release
    // the connection (and thus cause serialization to fail)
    ScrollableResults sr = s.createQuery("from Silly").scroll();
    try {
        SerializationHelper.serialize(s);
        fail("Serialization allowed on connected session; or aggressive release released connection with open resources");
    } catch (IllegalStateException e) {
    // expected behavior
    }
    // getting the first row only because SybaseASE15Dialect throws NullPointerException
    // if data is not read beforeQuery closing the ResultSet
    sr.next();
    // Closing the ScrollableResults does currently force batching to
    // aggressively release the connection
    sr.close();
    SerializationHelper.serialize(s);
    s.delete(silly);
    s.flush();
    release(s);
    done();
}