I have a code that saves a bean, and updates another bean in a DB via Hibernate. It must be do in the same transaction, because if something wrong occurs (f.ex launches a Exception) rollback must be executed for the two operations.
public class BeanDao extends ManagedSession {
public Integer save(Bean bean) {
Session session = null;
try {
session = createNewSessionAndTransaction();
Integer idValoracio = (Integer) session.save(bean); // SAVE
doOtherAction(bean); // UPDATE
commitTransaction(session);
return idBean;
} catch (RuntimeException re) {
log.error("get failed", re);
if (session != null) {
rollbackTransaction(session);
}
throw re;
}
}
private void doOtherAction(Bean bean) {
Integer idOtherBean = bean.getIdOtherBean();
OtherBeanDao otherBeanDao = new OtherBeanDao();
OtherBean otherBean = otherBeanDao.findById(idOtherBean);
.
. (doing operations)
.
otherBeanDao.attachDirty(otherBean)
}
}
The problem is:
In case that
session.save(bean)
launches an error, then I get AssertionFailure, because the function doOtherAction (that is used in other parts of the project) uses session after a Exception is thrown.
The first thing I thought were extract the code of the function doOtherAction, but then I have the same code duplicate, and not seems the best practice to do it.
What is the best way to refactor this?
It's a common practice to manage transactions at one level above DAOs, in services or other business logic classes. That way you can, based on the business/service logic, in one case do two DAO operations in one transaction and, in another case, do them in separate transactions.
I'm a huge fan of Declarative Transaction Management. If you can spare the time to get it working (piece of cake with an Application Server such as GlassFish or JBoss, and easy with Spring). If you annotate your business method with #TransactionAttribute(REQUIRED) (it can even be set to be done as default) and it calls the two DAO methods you will get exactly what you want: everything gets committed at once or rolled back over an Exception.
This solution is about as loosely coupled as it gets.
The others are correct in that they take in to account what are common practice currently.
But that doesn't really help you with your current practice.
What you should do is create two new DAO methods. Such as CreateGlobalSession and CommitGlobalSession.
What these do is the same thing as your current create and commit routines.
The difference is that they set a "global" session variable (most likely best done with a ThreadLocal). Then you change the current routines so that they check if this global session already exists. If your create detects the global session, then simply return it. If your commit detects the global session, then it does nothing.
Now when you want to use it you do this:
try {
dao.createGlobalSession();
beanA.save();
beanb.save();
Dao.commitGlobalSession();
} finally {
dao.rollbackGlobalSession();
}
Make sure you wrap the process in a try block so that you can reset your global session if there's an error.
While the other techniques are considered best practice and ideally you could one day evolve to something like that, this will get you over the hump with little more than 3 new methods and changing two existing methods. After that the rest of your code stays the same.
Related
I want to publish an event if and only if there were changes to the DB. I'm running under #Transaction is Spring context and I come up with this check:
Session session = entityManager.unwrap(Session.class);
session.isDirty();
That seems to fail for new (Transient) objects:
#Transactional
public Entity save(Entity newEntity) {
Entity entity = entityRepository.save(newEntity);
Session session = entityManager.unwrap(Session.class);
session.isDirty(); // <-- returns `false` ):
return entity;
}
Based on the answer here https://stackoverflow.com/a/5268617/672689 I would expect it to work and return true.
What am I missing?
UPDATE
Considering #fladdimir answer, although this function is called in a transaction context, I did add the #Transactional (from org.springframework.transaction.annotation) on the function. but I still encounter the same behaviour. The isDirty is returning false.
Moreover, as expected, the new entity doesn't shows on the DB while the program is hold on breakpoint at the line of the session.isDirty().
UPDATE_2
I also tried to change the session flush modes before calling the repo save, also without any effect:
session.setFlushMode(FlushModeType.COMMIT);
session.setHibernateFlushMode(FlushMode.MANUAL);
First of all, Session.isDirty() has a different meaning than what I understood. It tells if the current session is holding in memory queries which still haven't been sent to the DB. While I thought it tells if the transaction have changing queries. When saving a new entity, even in transaction, the insert query must be sent to the DB in order to get the new entity id, therefore the isDirty() will always be false after it.
So I ended up creating a class to extend SessionImpl and hold the change status for the session, updating it on persist and merge calls (the functions hibernate is using)
So this is the class I wrote:
import org.hibernate.HibernateException;
import org.hibernate.internal.SessionCreationOptions;
import org.hibernate.internal.SessionFactoryImpl;
import org.hibernate.internal.SessionImpl;
public class CustomSession extends SessionImpl {
private boolean changed;
public CustomSession(SessionFactoryImpl factory, SessionCreationOptions options) {
super(factory, options);
changed = false;
}
#Override
public void persist(Object object) throws HibernateException {
super.persist(object);
changed = true;
}
#Override
public void flush() throws HibernateException {
changed = changed || isDirty();
super.flush();
}
public boolean isChanged() {
return changed || isDirty();
}
}
In order to use it I had to:
extend SessionFactoryImpl.SessionBuilderImpl to override the openSession function and return my CustomSession
extend SessionFactoryImpl to override the withOptions function to return the extended SessionFactoryImpl.SessionBuilderImpl
extend AbstractDelegatingSessionFactoryBuilderImplementor to override the build function to return the extended SessionFactoryImpl
implement SessionFactoryBuilderFactory to implement getSessionFactoryBuilder to return the extended AbstractDelegatingSessionFactoryBuilderImplementor
add org.hibernate.boot.spi.SessionFactoryBuilderFactory file under META-INF/services with value of my SessionFactoryBuilderFactory implementation full class name (for the spring to be aware of it).
UPDATE
There was a bug with capturing the "merge" calls (as tremendous7 comment), so I end up capturing the isDirty state before any flush, and also checking it once more when checking isChanged()
The following is a different way you might be able to leverage to track dirtiness.
Though architecturally different than your sample code, it may be more to the point of your actual goal (I want to publish an event if and only if there were changes to the DB).
Maybe you could use an Interceptor listener to let the entity manager do the heavy lifting and just TELL you what's dirty. Then you only have to react to it, instead of prod it to sort out what's dirty in the first place.
Take a look at this article: https://www.baeldung.com/hibernate-entity-lifecycle
It has a lot of test cases that basically check for dirtiness of objects being saved in various contexts and then it relies on a piece of code called the DirtyDataInspector that effectively listens to any items that are flagged dirty on flush and then just remembers them (i.e. keeps them in a list) so the unit test cases can assert that the things that SHOULD have been dirty were actually flushed as dirty.
The dirty data inspector code is on their github. Here's the direct link for ease of access.
Here is the code where the interceptor is applied to the factory so it can be effective. You might need to write this up in your injection framework accordingly.
The code for the Interceptor it is based on has a TON of lifecycle methods you can probably exploit to get the perfect behavior for "do this if there was actually a dirty save that occured".
You can see the full docs of it here.
We do not know your complete setup, but as #Christian Beikov suggested in the comment, is it possible that the insertion was already flushed before you call isDirty()?
This would happen when you called repository.save(newEntity) without a running transaction, since the SimpleJpaRepository's save method is annotated itself with #Transactional:
#Transactional
#Override
public <S extends T> S save(S entity) {
...
}
This will wrap the call in a new transaction if none is already active, and flush the insertion to the DB at the end of the transaction just before the method returns.
You might choose to annotate the method where you call save and isDirty with #Transactional, so that the transaction is created when your method is called, and propagated to the repository call. This way the transaction would not be committed when the save returns, and the session would still be dirty.
(edit, just for completeness: in case of using an identity ID generation strategy, the insertion of newly created entity is flushed during a repository's save call to generate the ID, before the running transaction is committed)
I have this class and I tought three ways to handle detached entity state in case of persistence exceptions (which are handled elsewhere):
#ManagedBean
#ViewScoped
public class EntityBean implements Serializable
{
#EJB
private PersistenceService service;
private Document entity;
public void update()
{
// HANDLING 1. ignore errors
service.transact(em ->
{
entity = em.merge(entity);
// some other code that modifies [entity] properties:
// entity.setCode(...);
// entity.setResposible(...);
// entity.setSecurityLevel(...);
}); // an exception may be thrown on method return (rollback),
// but [entity] has already been reassigned with a "dirty" one.
//------------------------------------------------------------------
// HANDLING 2. ensure entity is untouched before flush is ok
service.transact(em ->
{
Document managed = em.merge(entity);
// some other code that modifies [managed] properties:
// managed.setCode(...);
// managed.setResposible(...);
// managed.setSecurityLevel(...);
em.flush(); // an exception may be thrown here (rollback)
// forcing method exit without [entity] being reassigned.
entity = managed;
}); // an exception may be thrown on method return (rollback),
// but [entity] has already been reassigned with a "dirty" one.
//------------------------------------------------------------------
// HANDLING 3. ensure entity is untouched before whole transaction is ok
AtomicReference<Document> reference = new AtomicReference<>();
service.transact(em ->
{
Document managed = em.merge(entity);
// some other code that modifies [managed] properties:
// managed.setCode(...);
// managed.setResposible(...);
// managed.setSecurityLevel(...);
reference.set(managed);
}); // an exception may be thrown on method return (rollback),
// and [entity] is safe, it's not been reassigned yet.
entity = reference.get();
}
...
}
PersistenceService#transact(Consumer<EntityManager> consumer) can throw unchecked exceptions.
The goal is to maintain the state of the entity aligned with the state of the database, even in case of exceptions (prevent entity to become "dirty" after transaction fail).
Method 1. is obviously naive and doesn't guarantee coherence.
Method 2. asserts that nothing can go wrong after flushing.
Method 3. prevents the new entity assigment if there's an exception in the whole transaction
Questions:
Is method 3. really safer than method 2.?
Are there cases where an exception is thrown between flush [excluded] and commit [included]?
Is there a standard way to handle this common problem?
Thank you
Note that I'm already able to rollback the transaction and close the EntityManager (PersistenceService#transact will do it gracefully), but I need to solve database state and the business objects do get out of sync. Usually this is not a problem. In my case this is the problem, because exceptions are usually generated by BeanValidator (those on JPA side, not on JSF side, for computed values that depends on user inputs) and I want the user to input correct values and try again, without losing the values he entered before.
Side note: I'm using Hibernate 5.2.1
this is the PersistenceService (CMT)
#Stateless
#Local
public class PersistenceService implements Serializable
{
#PersistenceContext
private EntityManager em;
#TransactionAttribute(TransactionAttributeType.REQUIRED)
public void transact(Consumer<EntityManager> consumer)
{
consumer.accept(em);
}
}
#DraganBozanovic
That's it! Great explanation for point 1. and 2.
I'd just love you to elaborate a little more on point 3. and give me some advice on real-world use case.
However, I would definitely not use AtomicReference or similar cumbersome constructs. Java EE, Spring and other frameworks and application containers support declaring transactional methods via annotations: Simply use the result returned from a transactional method.
When you have to modify a single entity, the transactional method would just take the detached entity as parameter and return the updated entity, easy.
public Document updateDocument(Document doc)
{
Document managed = em.merge(doc);
// managed.setXxx(...);
// managed.setYyy(...);
return managed;
}
But when you need to modify more than one in a single transaction, the method can become a real pain:
public LinkTicketResult linkTicket(Node node, Ticket ticket)
{
LinkTicketResult result = new LinkTicketResult();
Node managedNode = em.merge(node);
result.setNode(managedNode);
// modify managedNode
Ticket managedTicket = em.merge(ticket);
result.setTicket(managedTicket);
// modify managedTicket
Remark managedRemark = createRemark(...);
result.setRemark(managedemark);
return result;
}
In this case, my pain:
I have to create a dedicated transactional method (maybe a dedicated #EJB too)
That method will be called only once (will have just one caller) - is a "one-shot" non-reusable public method. Ugly.
I have to create the dummy class LinkTicketResult
That class will be instantiated only once, in that method - is "one-shot"
The method could have many parameters (or another dummy class LinkTicketParameters)
JSF controller actions, in most cases, will just call a EJB method, extract updated entities from returned container and reassign them to local fields
My code will be steadily polluted with "one-shotters", too many for my taste.
Probably I'm not seeing something big that's just in front of me, I'll be very grateful if you can point me in the right direction.
Is method 3. really safer than method 2.?
Yes. Not only is it safer (see point 2), but it is conceptually more correct, as you change transaction-dependent state only when you proved that the related transaction has succeeded.
Are there cases where an exception is thrown between flush [excluded] and commit [included]?
Yes. For example:
LockMode.OPTIMISTIC:
Optimistically assume that transaction will not experience contention
for entities. The entity version will be verified near the transaction
end.
It would be neither performant nor practically useful to check optimistick lock violation during each flush operation within a single transaction.
Deferred integrity constraints (enforced at commit time in db). Not used often, but are an illustrative example for this case.
Later maintenance and refactoring. You or somebody else may later introduce additional changes after the last explicit call to flush.
Is there a standard way to handle this common problem?
Yes, I would say that your third approach is the standard one: Use the results of a complete and successful transaction.
However, I would definitely not use AtomicReference or similar cumbersome constructs. Java EE, Spring and other frameworks and application containers support declaring transactional methods via annotations: Simply use the result returned from a transactional method.
Not sure if this is entirely to the point, but there is only one way to recover after exceptions: rollback and close the EM. From https://docs.jboss.org/hibernate/entitymanager/3.6/reference/en/html/transactions.html#transactions-basics-issues
An exception thrown by the Entity Manager means you have to rollback
your database transaction and close the EntityManager immediately
(discussed later in more detail). If your EntityManager is bound to
the application, you have to stop the application. Rolling back the
database transaction doesn't put your business objects back into the
state they were at the start of the transaction. This means the
database state and the business objects do get out of sync. Usually
this is not a problem, because exceptions are not recoverable and you
have to start over your unit of work after rollback anyway.
-- EDIT--
Also see http://piotrnowicki.com/2013/03/jpa-and-cmt-why-catching-persistence-exception-is-not-enough/
ps: downvote is not mine.
There are countless questions here, how to solve the "could not initialize proxy" problem via eager fetching, keeping the transaction open, opening another one, OpenEntityManagerInViewFilter, and whatever.
But is it possible to simply tell Hibernate to ignore the problem and pretend the collection is empty? In my case, not fetching it before simply means that I don't care.
This is actually an XY problem with the following Y:
I'm having classes like
class Detail {
#ManyToOne(optional=false) Master master;
...
}
class Master {
#OneToMany(mappedBy="master") List<Detail> details;
...
}
and want to serve two kinds of requests: One returning a single master with all its details and another one returning a list of masters without details. The result gets converted to JSON by Gson.
I've tried session.clear and session.evict(master), but they don't touch the proxy used in place of details. What worked was
master.setDetails(nullOrSomeCollection)
which feels rather hacky. I'd prefer the "ignorance" as it'd be applicable generally without knowing what parts of what are proxied.
Writing a Gson TypeAdapter ignoring instances of AbstractPersistentCollection with initialized=false could be a way, but this would depend on org.hibernate.collection.internal, which is surely no good thing. Catching the exception in the TypeAdapter doesn't sound much better.
Update after some answers
My goal is not to "get the data loaded instead of the exception", but "how to get null instead of the exception"
I
Dragan raises a valid point that forgetting to fetch and returning a wrong data would be much worse than an exception. But there's an easy way around it:
do this for collections only
never use null for them
return null rather than an empty collection as an indication of unfetched data
This way, the result can never be wrongly interpreted. Should I ever forget to fetch something, the response will contain null which is invalid.
You could utilize Hibernate.isInitialized, which is part of the Hibernate public API.
So, in the TypeAdapter you can add something like this:
if ((value instanceof Collection) && !Hibernate.isInitialized(value)) {
result = new ArrayList();
}
However, in my modest opinion your approach in general is not the way to go.
"In my case, not fetching it before simply means that I don't care."
Or it means you forgot to fetch it and now you are returning wrong data (worse than getting the exception; the consumer of the service thinks the collection is empty, but it is not).
I would not like to propose "better" solutions (it is not topic of the question and each approach has its own advantages), but the way that I solve issues like these in most use cases (and it is one of the ways commonly adopted) is using DTOs: Simply define a DTO that represents the response of the service, fill it in the transactional context (no LazyInitializationExceptions there) and give it to the framework that will transform it to the service response (json, xml, etc).
What you can try is a solution like the following.
Creating an interface named LazyLoader
#FunctionalInterface // Java 8
public interface LazyLoader<T> {
void load(T t);
}
And in your Service
public class Service {
List<Master> getWithDetails(LazyLoader<Master> loader) {
// Code to get masterList from session
for(Master master:masterList) {
loader.load(master);
}
}
}
And call this service like below
Service.getWithDetails(new LazyLoader<Master>() {
public void load(Master master) {
for(Detail detail:master.getDetails()) {
detail.getId(); // This will load detail
}
}
});
And in Java 8 you can use Lambda as it is a Single Abstract Method (SAM).
Service.getWithDetails((master) -> {
for(Detail detail:master.getDetails()) {
detail.getId(); // This will load detail
}
});
You can use the solution above with session.clear and session.evict(master)
I have raised a similar question in the past (why dependent collection isn't evicted when parent entity is), and it has resulted an answer which you could try for your case.
The solution for this is to use queries instead of associations (one-to-many or many-to-many). Even one of the original authors of Hibernate said that Collections are a feature and not an end-goal.
In your case you can get better flexibility of removing the collections mapping and simply fetch the associated relations when you need them in your data access layer.
You could create a Java proxy for every entity, so that every method is surrounded by a try/catch block that returns null when a LazyInitializationException is catched.
For this to work, all your entities would need to implement an interface and you'd need to reference this interface (instead of the entity class) all throughout your program.
If you can't (or just don't want) to use interfaces, then you could try to build a dynamic proxy with javassist or cglib, or even manually, as explained in this article.
If you go by common Java proxies, here's a sketch:
public static <T> T ignoringLazyInitialization(
final Object entity,
final Class<T> entityInterface) {
return (T) Proxy.newProxyInstance(
entityInterface.getClassLoader(),
new Class[] { entityInterface },
new InvocationHandler() {
#Override
public Object invoke(
Object proxy,
Method method,
Object[] args)
throws Throwable {
try {
return method.invoke(entity, args);
} catch (InvocationTargetException e) {
Throwable cause = e.getTargetException();
if (cause instanceof LazyInitializationException) {
return null;
}
throw cause;
}
}
});
}
So, if you have an entity A as follows:
public interface A {
// getters & setters and other methods DEFINITIONS
}
with its implementation:
public class AImpl implements A {
// getters & setters and other methods IMPLEMENTATIONS
}
Then, assuming you have a reference to the entity class (as returned by Hibernate), you could create a proxy as follows:
AImpl entityAImpl = ...; // some query, load, etc
A entityA = ignoringLazyInitialization(entityAImpl, A.class);
NOTE 1: You'd need to proxy collections returned by Hibernate as well (left as an excersice to the reader) ;)
NOTE 2: Ideally, you should do all this proxying stuff in a DAO or in some type of facade, so that everything is transparent to the user of the entities
NOTE 3: This is by no means optimal, since it creates a stacktrace for every access to an non-initialized field
NOTE 4: This works, but adds complexity; consider if it's really necessary.
So I have a interesting problem that i will need some help with. I know a bunch of questions have been asked around rollbacks in transactions using junit but I believe my problem and slightly different. To give people a better understanding of the problem let me start from the beginning.
I have implemented a UserManagementService with its respective DAO for a user management system. There is a general method called CreateUser(User obj) that is used to create a unique user. Now, there is a constraint set that email addresses are unique so if we try to invoke this method with a email address that has already been used, we throw a custom exception called UserManagementException with its respective error message. All this works fine however, the problem I am having is when it comes to the unit test. Oh, before i forget, let me mention the software stack i am using [Java, spring, hibernate]
I have my unit test class annotated with the Transactional annotations for each method that actually hits the db. These methods also have the #Rollback annotation so that all inserts, updates and deletions are rolled back at the end of each test invocation. So the problem i am facing here is I would like to test for the unique user constraint scenario. By calling the createUser(obj) a second time with a user object with the same email address I want to ensure that the UserManagementException exception is thrown. However, since it is transactional, whenever a exception is thrown, the transaction is rollback before the unit test completes and hence fails the test. Below is the test case.
#Test
#Rollback
#Transactional
public void testUniqueCreateConsoleUser() {
boolean success;
ConsoleUser newUser;
//first one
userManagementDao.createConsoleUser(user);
//second one. This shd throw a UserManagementException
try {
//now try and insert a new user with same email
newUser = new ConsoleUser("Queen", "Kong", "king.kong#blah.com", "kingkong","Universal Studios", "America/Los_Angeles", false, null);
userManagementDao.createConsoleUser(newUser);
//if this passed this is a problem. Console users should have unique email address
success = false;
} catch (UserManagementException e) {
success = true;
}
Assert.assertTrue(success);
}
The weird thing is when i am running it through the debugger, the Assert.assertTrue() method is invoked correctly but the test ultimately fails.
Another thing i tried was to add a prop to the #Transactional annotation. I added the flowing #Transactional(noRollbackFor = UserManagementException.class) in hopes that if the exception was thrown, the rollback wouldn't be invoked then but at the end of the test. I may be approaching this the wrong way so any ideas or best practices around this sort of testing would be greatly appricieated.
Note: Below is a snippet from the stacktrace..
org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:695)
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:321)
at org.springframework.transaction.aspectj.AbstractTransactionAspect.ajc$afterReturning$org_springframework_transaction_aspectj_AbstractTransactionAspect
It's hard to tell from your example, but you seem to be testing against your actual DAO implementation. Rather than have unit test data hitting your actual database, mock your DAO with either a mock implementation or a mocking framework. You can then manipulate the data returned programmatically and contort it into whatever validation scenarios you want.
If you can confirm that an extra rollback is thrown (for example - when spring does the insert, when it sees that it fails, does it already roll the transaction back?) then you should catch the rollback, or configure spring not to roll the transaction back.
That is, clearly, the rollback which spring is implementing is conflicting with the expected rollback in your unit test. This rollback is then confusing the rollback annotation, causing an unexpected thrown exception in the "unit-test / Spring ether".
THE SIMPLE SOLUTION : Don't enable the automated rollbacks for this test. Tests don't always have to be perfectly elegant.
Rather than inserting a user and then inserting another user with the same email address I suggest first loading an existing user from the database and then attempting to insert anther with the same email address as the one that was retrieved. If so you simply need to do:
#Test(expected = UserManagementException.class)
public void insert_duplicate_user() throws Exception {
// Read user from database
final ConsoleUser user = dao.load(...);
// Create new user with same email address.
final ConsoleUser newUser = new ConsoleUser (...);
newUser.setEmail(user.getEmail());
// Write
dao.createConsoleUser(newUser);
/*
* If you get here, there is a problem with your DAO logic
* and a new user (with the same email was created).
* So, we need to clean that up
*/
// Delete new user
dao.deleteUser(newUser);
}
This test will fail unless a UserManagementException is thrown.
My application loads entities from a Hibernate DAO, with OpenSessionInViewFilter to allow rendering.
In some cases I want to make a minor change to a field -
Long orderId ...
link = new Link("cancel") {
#Override public void onClick() {
Order order = orderDAO.load(orderId);
order.setCancelledTime(timeSource.getCurrentTime());
};
but such a change is not persisted, as the OSIV doesn't flush.
It seems a real shame to have to call orderDOA.save(order) in these cases, but I don't want to go as far as changing the FlushMode on the OSIV.
Has anyone found any way of declaring a 'request handling' (such as onClick) as requiring a transaction?
Ideally I suppose the transaction would be started early in the request cycle, and committed by the OSIV, so that all logic and rendering would take place in same transaction.
I generally prefer to use additional 'service' layer of code that wraps basic DAO
logic and provides transactions via #Transactional. That gives me better separation of presentation vs business logic and is
easier to test.
But since you already use OSIV may be you can just put some AOP interceptor around your code
and have it do flush()?
Disclaimer : I've never actually tried this, but I think it would work. This also may be a little bit more code than you want to write. Finally, I'm assuming that your WebApplication subclasses SpringWebApplication. Are you with me so far?
The plan is to tell Spring that we want to run the statements of you onClick method in a transaction. In order to do that, we have to do three things.
Step 1 : inject the PlatformTransactionManager into your WebPage:
#SpringBean
private PlatformTransactionManager platformTransactionManager;
Step 2 : create a static TransactionDefinition in your WebPage that we will later reference:
protected static final TransactionDefinition TRANSACTION_DEFINITION;
static {
TRANSACTION_DEFINITION = new DefaultTransactionDefinition(TransactionDefinition.PROPAGATION_REQUIRES_NEW);
((DefaultTransactionDefinition) TRANSACTION_DEFINITION).setIsolationLevel(TransactionDefinition.ISOLATION_SERIALIZABLE);
}
Feel free to change the TransactionDefinition settings and/or move the definition to a shared location as appropriate. This particular definition instructs Spring to start a new transaction even if there's already one started and to use the maximum transaction isolation level.
Step 3 : add transaction management to the onClick method:
link = new Link("cancel") {
#Override
public void onClick() {
new TransactionTemplate(platformTransactionManager, TRANSACTION_DEFINITION).execute(new TransactionCallback() {
#Override
public Object doInTransaction(TransactionStatus status) {
Order order = orderDAO.load(orderId);
order.setCancelledTime(timeSource.getCurrentTime());
}
}
}
};
And that should do the trick!