I'm updating an entity via EntityManager#merge() but the new JPA version number from JPA isn't being reflected correctly in the returned entity.
#Stateless
#TransactionAttribute(TransactionAttributeType.REQUIRED)
public class LeadService {
#PersistenceContext(name = "joose")
private EntityManager em;
public Lead createOrUpdateLead(Lead lead) {
if (lead.getId() != null) {
em.merge(lead);
} else {
em.persist(lead);
}
return lead;
}
How should I deal with this? Thanks!
Related
I want to reuse my AbstractDAO in a new project, except this time I don't want to use EJB annotations - just CDI ones.
So far, I've been using it like this:
public abstract class AbstractDAO<T> {
#PersistenceContext(unitName = "myUnit")
private EntityManager entityManager;
private Class<T> entityClass;
public AbstractDAO(Class<T> entityClass) {
this.entityClass = entityClass;
}
protected EntityManager getEntityManager() {
return entityManager;
}
public void save(T entity) {
entityManager.persist(entity);
}
public void update(T entity) {
entityManager.merge(entity);
}
public void remove(T entity) {
entityManager.remove(entityManager.merge(entity));
}
public T findById(Object id) {
return entityManager.find(entityClass, id);
}
public List<T> findBy(String attrName, Object attrValue) {
// Impl here
}
// [...] Many more search methods
}
And I've been creating a DAO for each Entity, like this for example:
#Stateless
public class UserDAO extends AbstractDAO<User> {
public UserDAO() {
super(User.class);
}
public User findByUsername(String username) {
if (username != null) {
return super.findOneBy("username", username.toLowerCase());
}
return null;
}
}
Now I would like to get rid of the #Stateless annotation. But simply replacing it with a #RequestScoped one won't work because of the non-private constructor with no parameters requirement of JSR-346
How can I refactor my DAO to a pure CDI one ?
Two issues here: CDI beans are not transaction aware by default -unlike EJBs, so you will have to use #Transactional qualifier if you want to do saves/updates...
Second, your no-arg constructor: you only need to pass the entity class to your abstract class even though you also specify it as a generic argument. You can infer the actual class like this:
public class AbstractDAO<T> {
private transient Class<T> entityClass;
#SuppressWarnings("unchecked")
public AbstractDAO() {
Type generSuperCls = getClass().getGenericSuperclass();
if (generSuperCls instanceof Class) {
generSuperCls = ((Class<?>) generSuperCls).getGenericSuperclass();
}
ParameterizedType parameterizedType = (ParameterizedType) generSuperCls;
Type type = parameterizedType.getActualTypeArguments()[0];
if (type instanceof Class) {
this.entityClass = (Class<T>) type;
} else if (type instanceof ParameterizedType) {
this.entityClass = (Class<T>) ((ParameterizedType) type).getRawType();
}
}
#PersistenceContext
private EntityManager em;
public T getById(Object id) throws ServiceException {
return getEm().find(entityClass, id);
}
// other methods follow
}
As a side note, why do you want to get rid of EJBs? Benchmarks show you get better performance using pooled slsb than cdi and they together very well(every EJB beans is also a CDI bean in jee container).
I have a library with some functionality that I want to reuse in other projects. My issue is that my service requires writing to the database. I would like for my library to use the datasource of the project that is inject my service.
Here is the minimal setup of my service
#Stateless
public class CustomService {
//to be added in producer
private EntityManager em;
private Principal principal;
//default constructor
public CustomService() {}
//custom constructor called in provider
public CustomService(Principal p, EntityManager e) {
principal = p;
em = e;
}
#TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
#Transactional
public CustomJPAObject createObject(...params...) {
//create JPA Object
em.persist(customObject);
em.flush();
return customObject;
}
}
I created a Custom Annotation for overriding the datasource
#Qualifier
#Retention(RetentionPolicy.RUNTIME)
#Target({ElementType.TYPE,ElementType.FIELD, ElementType.METHOD})
public #interface DynamicDS {
#Nonbinding String value() default "";
}
I also created a Singleton to be an EntityManager Producer
#Singleton
public class CustomEMProducer {
private Map<String, EntityManagerFactory> emfMap = new HashMap<>();
#Produces #Dependent #DynamicDS
public EntityManager produceEntityManager(InjectionPoint injectionPoint) {
String dataSourceName = null;
for(Annotation qualifier: injectionPoint.getQualifiers()) {
if(qualifier instanceof DynamicDS) {
DynamicDS dds = (DynamicDS) qualifier;
dataSourceName = dds.value();
break;
}
}
EntityManagerFactory emf = emfMap.get(dataSourceName);
if (emf == null) {
emf = Persistence.createEntityManagerFactory(dataSourceName);
emfMap.put(dataSourceName, emf);
}
return emf.createEntityManager();
}
#PostConstruct
public void cleanup() {
emfMap.entrySet().stream().forEach(entry -> entry.getValue().close());
}
}
Here is the code for my Service Producer
#Stateless
public class CustomServiceProvider {
#Inject private Principal principal;
#Produces #Dependent #DynamicDS
public BackgroundJobService getBackgroundJobService(InjectionPoint injectionPoint) throws EntityManagerNotCreatedException {
Annotation dsAnnotation = null;
for(Annotation qualifier: injectionPoint.getQualifiers()) {
if(qualifier instanceof BackgroundJobDS) {
dsAnnotation = qualifier;
break;
}
}
if (dsAnnotation != null) {
EntityManager em = CDI.current().select(EntityManager.class, dsAnnotation).get();
CustomService service = new CustomService(principal, em);
return service;
}
throw new EntityManagerNotCreatedException("Could not Produce CustomService");
}
}
The following is where I try to inject my new service
#Stateless
public class ProjectService {
#Inject #DynamicDS("project-ds") CustomerService service;
public CustomObject create(...params...) {
return service.createObject(...params...);
}
}
When I deploy my code and attempt to call the injected service I get the following error:
Caused by: javax.persistence.TransactionRequiredException: no transaction is in progress
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.checkTransactionNeeded(AbstractEntityManagerImpl.java:1171)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:1332)
...
It looks like all of the different levels of providers are preventing the #Transactional on the CustomService.createObject() method call from propagating the transaction. Does anyone have insight into why this is or an alternate way of accomplishing my goal of injecting a dynamic EntityManager?
After much experimenting, I was unable to get dynamically generate an EntityManager through the above code. After much research, I gave up on trying to pass in the name from outside the 3rd part library. I would up creating the following interface:
public interface CustomEntityManager {
EntityManager getEntityManager();
}
This meant that inside the project that uses the 3rd party service I can do the create the following implementation to inject the EntityManager
public ProjectSpecificEntityManager implements CustomEntityManager {
#PersistenceContext(unitname = "project-ds")
private EntityManager em;
public EntityManager getEntityManager() {
return em;
}
}
I had to update my CustomService to the following
#Stateless
public class CustomService {
//Ignore warning about no bean eligible because it is intended
//that the project that uses this library will provide the
//implementation
#SuppressWarnings("cdi-ambiguous-dependency")
#Inject
CustomEntityManager cem;
#TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
#Transactional
public CustomJPAObject createObject(...params...) {
//create JPA Object
cem.getEntityManager().persist(customObject);
return customObject;
}
}
In JPA, when doing bulk operations such as this
update LogEntry e set e.customer = null where e.customer.id = :cid
It is recommended to use a separate entity manager to avoid breaking synchronization, according to this: UPDATE SET Queries in JPA/JPQL
For example, the EntityManager may not be aware that a cached entity object in its persistence context has been modified by an UPDATE query. Therefore, it is a good practice to use a separate EntityManager for UPDATE queries.
How do I create a separate entity manager in a JTA environment such as Wildfly using hibernate? Do I need to create a separate persistence unit for bulk operations?
EDIT: Given I dont need a separate PU for bulk operations, is this a sufficient way of solving it using a new transaction?
#Transactional
public class JpaCustomerRepository implements CustomerRepository {
#Inject
private EntityManager em;
...
#Override
public Customer remove(long id) {
CustomerEntity entity = em.find(CustomerEntity.class, id);
if (entity != null) {
updateLogEntriesToNull(entity);
em.remove(entity);
return entity;
} else {
return null;
}
}
#Transactional(value=TxType.REQUIRES_NEW)
public void updateLogEntriesToNull(CustomerEntity entity) {
em.createNamedQuery(LogEntry.updateCustomerToNull)
.setParameter("cid", entity.getId())
.executeUpdate();
}
...
}
Where LogEntry.updateCustomerToNull is the bulk query.
Answer: This does not work because the interceptor is not invoked when called from inside the same class.
EDIT2: Following the suggestions from Andrei, this should work:
#Transactional
public class JpaCustomerRepository implements CustomerRepository {
public static class BulkUpdater {
#Inject
private EntityManager em;
#Transactional(value=TxType.REQUIRES_NEW)
public void updateLogEntriesToNull(CustomerEntity entity) {
em.createNamedQuery(LogEntry.updateCustomerToNull)
.setParameter("cid", entity.getId())
.executeUpdate();
}
}
#Inject
private EntityManager em;
#Inject
private BulkUpdater bulkUpdater;
...
#Override
public Customer remove(long id) {
CustomerEntity entity = em.find(CustomerEntity.class, id);
if (entity != null) {
bulkUpdater.updateLogEntriesToNull(entity);
em.remove(entity);
return entity;
} else {
return null;
}
}
...
}
Testing confirms that the interceptor gets called twice.
The recommendation is valid only if you also do other stuff with the EntityManager (when there is a risk of manipulating/reading the same entities as the BULK UPDATE). The easiest solution: make sure that this BULK UPDATE is executed in a separate service, within a new transaction. No need to create a separate PU (persistence unit) for bulk operations.
How to reach the entity manager which managed the entity. I mean; suppose that i have an entity reference in the sessionBean, how can i get entityManager of this entity belonged one?
I had already tried (plz see getEntityManagerOfEntity() method) contains method of em; but it does not work.
Thx
bgrds
#Stateless(name = "MainManager", mappedName = "MainManager")
#TransactionManagement(TransactionManagementType.CONTAINER)
#Interceptors(value = { PerformanceMonitor.class, ProfileInterceptor.class })
public class MainManagerBean implements MainManager, MainManagerLocal
{
private Logger logger = Logger.getLogger(this.getClass());
#PersistenceContext(unitName = "DSApp")
private EntityManager manager;
#PersistenceContext(unitName = "DSIX")
private EntityManager integrationManager;
#Resource
SessionContext ctx;
public EntityManager getEntityManagerOfEntity(SuperEntity superEntity)
{
if (manager.contains(superEntity))
return manager;
else if (integrationManager.contains(superEntity))
return integrationManager;
return null;
}
public SuperEntity findByPrimaryKey(SuperEntity superEntity)
{
getEntityManagerOfEntity(superEntity).setFlushMode(FlushModeType.COMMIT);
return dao.findByPrimaryKey(getEntityManagerOfEntity(superEntity), superEntity);
You cannot backtrack the EntityManager from an entity using the JPA API, even when it is still managed.
What you can do, if you have references to different EMs in your bean and the entity is managed, is to check the right EM by calling em.contains(entity).
In most cases it is not really important to know, which EM has fetched an entity originally, since you can merge the entity into any persistence context and continue working with it.
What is the best way to handle transactions in this environment?
I have a Transacao class, which has a collection of Transacao.
public class Transacao {
#OneToMany(fetch = FetchType.LAZY, mappedBy = "pai")
private List<Transacao> filhos;
}
I load this in JSF from a EJB, something like:
public class TransacaoBean {
#EJB
private TransacaoService transacaoService;
private void edit(Long id) {
this.transacao = transacaoService.findById(id);
}
}
although, if I want to get the collection of filhos, I have to do this:
public class TransacaoBean {
...
private void edit(Long id) {
this.transacao = transacaoService.findById(id);
log.info(this.transacao.getFilhos.size()); //this throws a LazyInitializationException
}
}
and I get an Exception.
What is the best way to have this loaded in my JSF? I'm considering creating a Filter and using USerTransaction to keep the transaction open for the request or fetching the filhos in my EJB. Is there a better solution to this, which one is better?
The fetch's default value of the #OneToMany is FetchType.LAZY.
You can set it FetchType.EAGER to use them in non-managed environment.
Or you can make another EJB or method for getting a list or just the size.
public class TransacaoService {
public Transacao findById(final long id) {
...
}
public long getFilhosSize(final long id) {
// SELECT f FROM Transacao AS t WHERE t.pai.id=:id
}
#PersistenceContext
private EntityManager entityManager;
}