/**
* Makes a try to lock object. This will save us great number of SQL statements in several cases.
* It's not a big problem if locking is not possible.
*
* @param o object to lock.
* @param s session to lock object in.
*/
public static void lock(Object o, Session s) {
try {
s.lock(o, LockMode.NONE);
} catch (HibernateException e) {
// Well, it's possible that object is dirty.
}
}
/** obtains a pessimistic lock on the given process instance. */
public void lockProcessInstance(ProcessInstance processInstance) {
try {
session.lock(processInstance, LockMode.UPGRADE);
} catch (HibernateException e) {
handle(e);
throw new JbpmPersistenceException("could not lock " + processInstance, e);
}
}
@Override
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
Session session = RequestAdapter.getSession(request);
TaskDAOIf taskDAO = DAOFactory.TaskDAOIf(session);
Task task = taskDAO.getTask(Util.parseInteger(request.getParameter("taskid"), 0));
if (task == null) {
request.setAttribute("title", "Aufgabe nicht gefunden");
request.getRequestDispatcher("MessageView").forward(request, response);
return;
}
// check Lecture Participation
ParticipationDAOIf participationDAO = DAOFactory.ParticipationDAOIf(session);
Participation participation =
participationDAO.getParticipation(
RequestAdapter.getUser(request), task.getTaskGroup().getLecture());
if (participation == null
|| participation.getRoleType().compareTo(ParticipationRole.ADVISOR) != 0) {
response.sendError(HttpServletResponse.SC_FORBIDDEN, "insufficient rights");
return;
}
if (task.getDeadline().after(Util.correctTimezone(new Date()))
|| task.getShowPoints() != null) {
request.setAttribute("title", "Ungültige Anfrage");
request.getRequestDispatcher("MessageView").forward(request, response);
return;
}
Transaction tx = session.beginTransaction();
session.lock(task, LockMode.UPGRADE);
if (request.getParameter("mail") != null) {
for (Submission submission : task.getSubmissions()) {
for (Participation submitterParticipation : submission.getSubmitters()) {
if (submission.getPoints() != null && submission.getPoints().getPointsOk()) {
// HACK hardcoded URL
MailSender.sendMail(
submitterParticipation.getUser().getFullEmail(),
"Bewertung erfolgt",
"Hallo "
+ submitterParticipation.getUser().getFullName()
+ ",\n\neine Ihrer Abgaben wurde bewertet.\n\nEinsehen: <https://si.in.tu-clausthal.de/submissionsystem/servlets/ShowTask?taskid="
+ task.getTaskid()
+ ">.\n\n-- \nReply is not possible.");
}
}
}
}
task.setShowPoints(task.getDeadline());
session.saveOrUpdate(task);
tx.commit();
response.sendRedirect(response.encodeRedirectURL("ShowTask?taskid=" + task.getTaskid()));
}
public void attachClean(Testwordcase instance) {
log.debug("attaching clean Testwordcase instance");
Session session = sessionFactory.openSession();
try {
session.lock(instance, LockMode.NONE);
log.debug("attach successful");
session.close();
} catch (RuntimeException re) {
session.close();
log.error("attach failed", re);
throw re;
}
}
/**
* Test the equivalent of EJB3 LockModeType.READ
*
* <p>From the spec:
*
* <p>If transaction T1 calls lock(entity, LockModeType.READ) on a versioned object, the entity
* manager must ensure that neither of the following phenomena can occur:
*
* <ul>
* <li>P1 (Dirty read): Transaction T1 modifies a row. Another transaction T2 then reads that
* row and obtains the modified value, before T1 has committed or rolled back. Transaction
* T2 eventually commits successfully; it does not matter whether T1 commits or rolls back
* and whether it does so before or after T2 commits.
* <li>P2 (Non-repeatable read): Transaction T1 reads a row. Another transaction T2 then
* modifies or deletes that row, before T1 has committed. Both transactions eventually
* commit successfully.
* <p>This will generally be achieved by the entity manager acquiring a lock on the
* underlying database row. Any such lock may be obtained immediately (so long as it is
* retained until commit completes), or the lock may be deferred until commit time (although
* even then it must be retained until the commit completes). Any implementation that
* supports repeatable reads in a way that prevents the above phenomena is permissible.
* <p>The persistence implementation is not required to support calling lock(entity,
* LockMode-Type.READ) on a non-versioned object. When it cannot support such a lock call,
* it must throw the PersistenceException. When supported, whether for versioned or
* non-versioned objects, LockMode-Type.READ must always prevent the phenomena P1 and P2.
* Applications that call lock(entity, LockModeType.READ) on non-versioned objects will not
* be portable.
* <p>Odd as it may sound, EJB3 LockModeType.READ actually maps to the Hibernate
* LockMode.UPGRADE
*/
public void testLockModeTypeRead() {
if (!readCommittedIsolationMaintained("ejb3 lock tests")) {
return;
}
if (getDialect().doesReadCommittedCauseWritersToBlockReaders()) {
reportSkip("deadlock", "jpa read locking");
return;
}
final String initialName = "lock test";
// set up some test data
Session s1 = getSessions().openSession();
Transaction t1 = s1.beginTransaction();
Item item = new Item();
item.setName(initialName);
s1.save(item);
t1.commit();
s1.close();
Long itemId = item.getId();
// perform the isolated update
s1 = getSessions().openSession();
t1 = s1.beginTransaction();
item = (Item) s1.get(Item.class, itemId);
s1.lock(item, LockMode.UPGRADE);
item.setName("updated");
s1.flush();
Session s2 = getSessions().openSession();
Transaction t2 = s2.beginTransaction();
Item item2 = (Item) s2.get(Item.class, itemId);
assertEquals("isolation not maintained", initialName, item2.getName());
t1.commit();
s1.close();
item2 = (Item) s2.get(Item.class, itemId);
assertEquals("repeatable read not maintained", initialName, item2.getName());
t2.commit();
s2.close();
s1 = getSessions().openSession();
t1 = s1.beginTransaction();
s1.delete(item);
t1.commit();
s1.close();
}
/**
* Test the equivalent of EJB3 LockModeType.READ
*
* <p>From the spec:
*
* <p>If transaction T1 calls lock(entity, LockModeType.READ) on a versioned object, the entity
* manager must ensure that neither of the following phenomena can occur:
*
* <ul>
* <li>P1 (Dirty read): Transaction T1 modifies a row. Another transaction T2 then reads that
* row and obtains the modified value, beforeQuery T1 has committed or rolled back.
* Transaction T2 eventually commits successfully; it does not matter whether T1 commits or
* rolls back and whether it does so beforeQuery or afterQuery T2 commits.
* <li>P2 (Non-repeatable read): Transaction T1 reads a row. Another transaction T2 then
* modifies or deletes that row, beforeQuery T1 has committed. Both transactions eventually
* commit successfully.
* <p>This will generally be achieved by the entity manager acquiring a lock on the
* underlying database row. Any such lock may be obtained immediately (so long as it is
* retained until commit completes), or the lock may be deferred until commit time (although
* even then it must be retained until the commit completes). Any implementation that
* supports repeatable reads in a way that prevents the above phenomena is permissible.
* <p>The persistence implementation is not required to support calling lock(entity,
* LockMode-Type.READ) on a non-versioned object. When it cannot support such a lock call,
* it must throw the PersistenceException. When supported, whether for versioned or
* non-versioned objects, LockMode-Type.READ must always prevent the phenomena P1 and P2.
* Applications that call lock(entity, LockModeType.READ) on non-versioned objects will not
* be portable.
* <p>EJB3 LockModeType.READ actually maps to the Hibernate LockMode.OPTIMISTIC
*/
@Test
public void testLockModeTypeRead() {
if (!readCommittedIsolationMaintained("ejb3 lock tests")) {
return;
}
final String initialName = "lock test";
// set up some test data
Session s1 = sessionFactory().openSession();
Transaction t1 = s1.beginTransaction();
Item item = new Item();
item.setName(initialName);
s1.save(item);
t1.commit();
s1.close();
Long itemId = item.getId();
// do the isolated update
s1 = sessionFactory().openSession();
t1 = s1.beginTransaction();
item = (Item) s1.get(Item.class, itemId);
s1.lock(item, LockMode.UPGRADE);
item.setName("updated");
s1.flush();
Session s2 = sessionFactory().openSession();
Transaction t2 = s2.beginTransaction();
Item item2 = (Item) s2.get(Item.class, itemId);
assertEquals("isolation not maintained", initialName, item2.getName());
t1.commit();
s1.close();
item2 = (Item) s2.get(Item.class, itemId);
assertEquals("repeatable read not maintained", initialName, item2.getName());
t2.commit();
s2.close();
s1 = sessionFactory().openSession();
t1 = s1.beginTransaction();
s1.delete(item);
t1.commit();
s1.close();
}
public void lock(String entityName, Object object, LockMode lockMode) throws HibernateException {
session.lock(entityName, object, lockMode);
}
public void lock(Object object, LockMode lockMode) throws HibernateException {
session.lock(object, lockMode);
}
/**
* Test the equivalent of EJB3 LockModeType.WRITE
*
* <p>From the spec:
*
* <p>If transaction T1 calls lock(entity, LockModeType.WRITE) on a versioned object, the entity
* manager must avoid the phenomena P1 and P2 (as with LockModeType.READ) and must also force an
* update (increment) to the entity's version column. A forced version update may be performed
* immediately, or may be deferred until a flush or commit. If an entity is removed beforeQuery a
* deferred version update was to have been applied, the forced version update is omitted, since
* the underlying database row no longer exists.
*
* <p>The persistence implementation is not required to support calling lock(entity,
* LockMode-Type.WRITE) on a non-versioned object. When it cannot support a such lock call, it
* must throw the PersistenceException. When supported, whether for versioned or non-versioned
* objects, LockMode-Type.WRITE must always prevent the phenomena P1 and P2. For non-versioned
* objects, whether or not LockModeType.WRITE has any additional behaviour is vendor-specific.
* Applications that call lock(entity, LockModeType.WRITE) on non-versioned objects will not be
* portable.
*
* <p>Due to the requirement that LockModeType.WRITE needs to force a version increment, a new
* Hibernate LockMode was added to support this behavior: {@link org.hibernate.LockMode#FORCE}.
*/
@Test
public void testLockModeTypeWrite() {
if (!readCommittedIsolationMaintained("ejb3 lock tests")) {
return;
}
final String initialName = "lock test";
// set up some test data
Session s1 = sessionFactory().openSession();
Transaction t1 = s1.beginTransaction();
Item item = new Item();
item.setName(initialName);
s1.save(item);
MyEntity myEntity = new MyEntity();
myEntity.setName("Test");
s1.save(myEntity);
t1.commit();
s1.close();
Long itemId = item.getId();
long initialVersion = item.getVersion();
s1 = sessionFactory().openSession();
t1 = s1.beginTransaction();
item = (Item) s1.get(Item.class, itemId);
s1.lock(item, LockMode.FORCE);
assertEquals("no forced version increment", initialVersion + 1, item.getVersion());
myEntity = (MyEntity) s1.get(MyEntity.class, myEntity.getId());
s1.lock(myEntity, LockMode.FORCE);
assertTrue("LockMode.FORCE on a un-versioned entity should degrade nicely to UPGRADE", true);
s1.lock(item, LockMode.FORCE);
assertEquals("subsequent LockMode.FORCE did not no-op", initialVersion + 1, item.getVersion());
Session s2 = sessionFactory().openSession();
Transaction t2 = s2.beginTransaction();
Item item2 = (Item) s2.get(Item.class, itemId);
assertEquals("isolation not maintained", initialName, item2.getName());
item.setName("updated-1");
s1.flush();
// currently an unfortunate side effect...
assertEquals(initialVersion + 2, item.getVersion());
t1.commit();
s1.close();
item2.setName("updated");
try {
t2.commit();
fail("optimistic lock should have failed");
} catch (Throwable ignore) {
// expected behavior
t2.rollback();
} finally {
s2.close();
}
s1 = sessionFactory().openSession();
t1 = s1.beginTransaction();
s1.delete(item);
s1.delete(myEntity);
t1.commit();
s1.close();
}