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Re: [eclipselink-users] Virtual Metlhods | questions 
Hi Tom,

  The issues currently I am facing are as follows
1) An application event (which is published on all the nodes in the cluster - coherence grid aware) is triggered when there is a need to create a mapping. (Works fine) 2) I have service named DynamicRecordWeaverImpl which creates the mappings as follows (Please verify, if below correct way of adding mappings. As chris mentioned I am not creating mapping on active session)
NOTE >> after weave method, I can see the need added relationship in the session. 
    @Autowired
    private DynamicRecordContext dynamicRecordContext;

    @Autowired
    @Qualifier("entityManagerFactory")
private LocalContainerEntityManagerFactoryBean localContainerEntityManagerFactoryBean; 

    /*
     * (non-Javadoc)
* @see com.oracle.healthinsurance.common.domain.internal.dyndata.components.DynamicRecordWeaver#weave() 
     */
    @SuppressWarnings("rawtypes")
    @Override
    public void weave() {
JpaEntityManagerFactory jpaEntityManagerFactory = JpaEntityManagerFactory.class.cast(localContainerEntityManagerFactoryBean 
                .getNativeEntityManagerFactory());

        Session session = jpaEntityManagerFactory.getServerSession();
for (Map.Entry<Class, ClassDescriptor> entry : session.getDescriptors().entrySet()) { 

            if (MetaModelUtil.isDynamicRecordContainer(entry.getKey())) {
Class<? extends DynamicRecordContainer<DynamicRecordStorable>> dynamicRecordContainerClass = CastUtil 
                        .uncheckedCast(entry.getKey());
Class<? extends DynamicRecordStorable> dynamicRecordStorableClass = CastUtil 
.uncheckedCast(GenericTypeResolver.resolveTypeArgument(dynamicRecordContainerClass,
                                DynamicRecordContainer.class));
ClassDescriptor dynamicRecordContainerClassCd = session.getDescriptor(dynamicRecordContainerClass); ClassDescriptor dynamicRecordStorableClassCd = session.getDescriptor(EclipseLinkMetadata 
.getDomainClass(dynamicRecordStorableClass));
Map<String, DynamicRecordSetup> dynamicRecordSetupMap = dynamicRecordContext 
.doGetDynamicRecordsSetup(dynamicRecordContainerClass);
for (Map.Entry<String, DynamicRecordSetup> setupEntry : dynamicRecordSetupMap.entrySet()) { 
                    String fieldName = setupEntry.getKey();
DynamicRecordSetup dynamicRecordSetup = setupEntry.getValue(); 

                    // OneToMany
oneToManyMapping(dynamicRecordContainerClassCd, fieldName, dynamicRecordStorableClassCd.getJavaClass());
for (FieldDetails fieldDetails : dynamicRecordSetup.getFieldDetailsList()) { 
                        // Add the attributes dynamicRecordStorableClass
                        String attributeName = fieldDetails.getCode();
                        String columnName = columnName(fieldDetails);
Class<?> attributeType = attributeType(fieldDetails);
directFieldMapping(dynamicRecordStorableClassCd, attributeName, columnName, attributeType); 
                    }
                }

            }

        }
        jpaEntityManagerFactory.refreshMetadata(null);
        System.gc();
3) You mentioned >> " The way refreshMetadata works, should allow your system to stay live. When you call refreshMetadata, all existing EntityManagers continue to operate on the previous metadata. The new metadata is only in effect for new EntityManagers. " Now I am searching for entity to which new mappings where added. What I found that entityManager does not contain the newly added mappings. I cann't figure out why?? It should be picked up?? so do I have keep adding the mappings for each session and call refreshMetadata, this doen't look elegant. Is some where there is caching of entity managers happening??? 



On 25-07-2012 01:56 PM, Tom Ware wrote:

Hi Gaurav,
I am assuming you've figured out how to get refreshMetadata to work for you to get your mappings added. EclipseLink itself does not provide a mechanism to trigger the refresh There are a number of options open to you depending on how your app is architected, JMS, RMI, ServerSentEvents, WebSockets, Oracle QCN/DCN combined with one of those technologies.
The way refreshMetadata works, should allow your system to stay live. When you call refreshMetadata, all existing EntityManagers continue to operate on the previous metadata. The new metadata is only in effect for new EntityManagers. 

-Tom

On 24/07/2012 8:12 PM, gaurav malhotra wrote:

I understand the problem, but I don't know how to fix it.
1) I am recording all the changes (we store them in the database)
2) I don't know how to signal that session needs to pick them using
refreshMetadata. Does this mean using SessionEventAdapter?? If yes then which method(s) should I use. As per my understanding refreshMetadata should be only called once if there are recorded changes. When recorded changes has been pushed to session, then there is no need to refreshMetadata. It will be great if you 
point me some code snippets.
Also, my product, is a claim processing system (with millions of transactions 
handled in a day). What is the impact of refreshMetadata on the running
transactions?? We dont expect setup for the dynamic fields change every another 
minute or a day??

On 25-07-2012 12:04 AM, Christopher Delahunt wrote:
Through a metadata source repository, or the customizer approach. Your app must record the changes that are needed somehow and then signal that the 
session needs to pick them up using refreshMetadata. The app should not
directly change the running session.
On 2012-07-24, at 5:47 PM, gaurav malhotra <gaurav.malhotra@xxxxxxxxxx> wrote: 


Hi Chris,
It's the requirement of my product - Dynamic Fields can be configured at the runtime and should be picked up in live application with zero down time. Its 
for the dynamic fields I am creating the mappings.
How to accomplish above reqirement?

~Gaurav
On 24-07-2012 11:29 PM, Christopher Delahunt wrote:
This would occur if the mapping has not been initialized; initialization occurs during session login. Earlier posts showed mappings being added through a session customizer which get called prior to login. How and when 
is this mapping added?
Calling refreshMetadata as Tom mentions creates a new session from the 
metadata, and would call customizers on it before logging in. If your
customizer picks up the new mapping changes, then that might explain why it 
works for you, since they get initialized with the new session login.
It is not a good idea to make mapping/descriptor changes to active sessions 
after login has occurred.

On 24/07/2012 5:05 PM, gaurav malhotra wrote:

ava.lang.NullPointerException
at
org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRowInternal(ForeignReferenceMapping.java:2019) 


at
org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRow(ForeignReferenceMapping.java:1987) 


at
org.eclipse.persistence.mappings.ForeignReferenceMapping.buildCloneFromRow(ForeignReferenceMapping.java:276) 


at
org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoWorkingCopyClone(ObjectBuilder.java:1548) 


at
org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildWorkingCopyCloneFromRow(ObjectBuilder.java:1694) 


at
org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObjectInUnitOfWork(ObjectBuilder.java:664) 


at
org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:601) 


at
org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:560) 


at
org.eclipse.persistence.queries.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:717) 


at
org.eclipse.persistence.queries.ReadAllQuery.registerResultInUnitOfWork(ReadAllQuery.java:769) 



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