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JPA – OSGi – Hibernate – JDK6 (part 1) - RCP

Written by yarenty

Thursday, 25 June 2009 11:40

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JPA – OSGi – Hibernate – JDK6 (part 1)
Running in OSGi container
Hacking Hibernate bundles
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When I started eclipse RCP application which trying to use the same code...

.. I surprisingly (or not surprisingly) see:

javax.persistence.PersistenceException: No Persistence provider for EntityManager named eireshop

at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:129)

at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:99)

at com.yarenty.eireshop.dao.helper.JPAHelper.getEntityManager(JPAHelper.java:59)

UPS…

Lets investigate:

Go to Osgi container and display all bundles:

osgi>ss

[..]

162 RESOLVED com.springsource.org.jboss.util_2.0.4.GA

163 RESOLVED com.springsource.com.mysql.jdbc_5.1.6

171 RESOLVED com.springsource.org.jgroups_2.5.1

179 RESOLVED com.springsource.javax.transaction_1.1.0

205 RESOLVED com.springsource.org.hibernate.annotations_3.4.0.GA

Master=228

208 RESOLVED com.springsource.org.hibernate.validator_3.1.0.GA

218 ACTIVE com.yarenty.eireshop.ui_1.0.0

226 ACTIVE com.springsource.antlr_2.7.7

227 RESOLVED com.springsource.javax.persistence_1.99.0

228 ACTIVE com.springsource.org.hibernate_3.3.1.GA

Fragments=205, 230

229 RESOLVED com.springsource.org.hibernate.annotations.common_3.3.0.ga

230 RESOLVED com.springsource.org.hibernate.ejb_3.4.0.GA

Master=228

231 RESOLVED com.yarenty.erieshop.dao_1.0.0

osgi>ss

All looks OK. But when I check source code for javax.persistence I’ve found that searching persistence providers looking for current thread classloader. That will not work in OSGi as current thread has visibility only for bundles that are declared in manifest.

public Collection<PersistenceProvider> findAllProviders() throws IOException {

ClassLoader loader = Thread.currentThread()

.getContextClassLoader();

Enumeration<URL> resources = loader

.getResources(SERVICE_PROVIDER_FILE);

Set<String> providerNames = new HashSet<String>();

while (resources.hasMoreElements()) {

URL url = resources.nextElement();

InputStream is = url.openStream();

try {

providerNames.addAll(

providerNamesFromReader(

new BufferedReader(

new InputStreamReader(is))));

} finally {

is.close();

}

Collection<PersistenceProvider> loadedProviders =

new HashSet<PersistenceProvider>();

for (String s : providerNames) {

try{

loadedProviders

.add((PersistenceProvider)loader

.loadClass(s).newInstance());

} catch (ClassNotFoundException exc){

} catch (InstantiationException exc){

} catch (IllegalAccessException exc){

}

return loadedProviders;

}

But I found that there is javax.persistence.osgi package, with activator and !!! tracker !!!. And that’s what I’m really looking for:

osgi> start 227

Persistence bundle starting...

Persistence bundle started.

Lets start one more time but this time with started persistence bundle:

osgi> Persistence bundle starting...

Persistence bundle started.

javax.persistence.PersistenceException: No Persistence provider for EntityManager named eireshop

at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:129)

at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:99)

at com.yarenty.eireshop.dao.helper.JPAHelper.getEntityManager(JPAHelper.java:59)

at com.yarenty.eireshop.dao.impl.UserHome.<clinit>(UserHome.java:34)

at com.yarenty.eireshop.ui.View.createPartControl(View.java:115)

at org.eclipse.ui.internal.ViewReference.createPartHelper(ViewReference.java:371)

at org.eclipse.ui.internal.ViewReference.createPart(ViewReference.java:230)

at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:594)

at org.eclipse.ui.internal.PartPane.setVisible(PartPane.java:306)

OSGi - Find all providers.

It’s working but couldn’t find providers.

osgi> Persistence bundle starting...

Persistence bundle started.

OSGi - Find all providers.

javax.persistence.PersistenceException: No Persistence provider for EntityManager named eireshop

at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:129)

at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:99)

at com.yarenty.eireshop.dao.helper.JPAHelper.getEntityManager(JPAHelper.java:59)

Ok, if it can’t find them itself – lets help them.In my Dao bundle I create Activator class.

package com.yarenty.eireshop.dao.activator;

import java.util.Date;

import java.util.Dictionary;

import java.util.Properties;

import org.hibernate.ejb.HibernatePersistence;

import org.osgi.framework.BundleActivator;

import org.osgi.framework.BundleContext;

import javax.persistence.spi.PersistenceProvider;

/**

* @author ejarnow

public class Activator implements BundleActivator {

private BundleContext context;

@Override

public void start(BundleContext context) throws Exception {

System.out.println(

"Registering persistence provider ;-)");

Properties properties = new Properties();

properties.put("javax.persistence.spi.PersistenceProvider",

"eireshop");

context.registerService(

PersistenceProvider.class.getName(),

new HibernatePersistence(),

properties);

}

@Override

public void stop(BundleContext context) throws Exception {

}

And output:

osgi> Persistence bundle starting...

Persistence bundle started.

Registering persistence provider ;-)

ProviderTracker: New service detected...

ProviderTracker: Added service eireshop