The @Transactional and @PersistenceContext annotations work exclusively
in blueprint or eventually pax-cdi with deltaspike.
For declarative services there is no extension model to add new
annotations. So we can not easily support annotations like above.
This is not a big issue though as we have alternative solutions in place.
See
http://liquid-reality.de/display/liquid/2015/06/30/Apache+Karaf+Tutorial+part+10+-+Declarative+services
For DS there is the JPATemplate from Aries JPA. It allows the same
feature set as the annotations for blueprint but works using closures
instead.
I used this a bit myself and while I first was very pro annotation I
changed my mind in the mean time. I think the closure based approach works
as nice and is less complex. Btw. I am experimenting with an alternative
approach using try with resources instead of closures. That would allow
a similar style but be even less complex.
There is also an alternative from the OSGi specs. It is called
tx-control and also hosted at Aries.
http://aries.apache.org/modules/tx-control/
It is similar to JPATemplate but a little different in style. The code
is written by Tim Ward and he also did a very good documentation for it.
Christian
On 10.03.2017 09:00, erwan wrote:
Sorry for the "timeout" before answering your comment but it took me some
time to have a look at all solutions that were proposed. What strikes me is
that, as you already stated, it is difficult to select a solution that is
simple, well documented and seen as a standard. It's a bit annoying as osgi
doesn't seem to be a young solution. By browsing the web, looking for
solutions, it seems to go in every directions.
To be more concrete, I tried to combine 2 solutions to my need : blueprint
and DS.
I'm not sure we can mix several solutions. I probably need to spend some
more time :)
First, I use blueprint solution to deploy a persistence bundle and Christian
tutorial site has been of a great help with that. Thanks to you.
Then I tried to add declarative service in the loop, using annotations as it
seemed practical to me.
For the moment, I'm not able to make this working so I hope you might take a
little bit more time to evangelize
Can I do this?
In the persistence bundle, after having installed hibernate feature:
@Component(immediate = true)
@Transactional
public class RepositoryImpl implements IRepository {
private EntityManager manager;
@PersistenceContext(unitName="db")
public void setEntityManager(EntityManager manager) {
this.manager = manager;
}
private UniqueIdManagerItf uniqueIdManager;
@Reference
public void setUniqueIdManager(UniqueIdManagerItf uniqueIdManager) {
this.uniqueIdManager = uniqueIdManager;
}
@Override
public void removeAll() {
ArrayList<String> uniqueIdList = new ArrayList<>();
uniqueIdList = uniqueIdManager.getUniqueIdList();
for (String id: uniqueIdList) {
uniqueIdManager.setIdAsAvailable(id);
}
manager.createQuery("DELETE FROM MyEntity").executeUpdate();
}
with a pom like this:
<configuration>
<instructions>
<Bundle-SymbolicName>${project.artifactId}</Bundle-symbolicName>
<Bundle-Version>${project.version}</Bundle-Version>
<supportedProjectTypes>
<supportedProjectType>bundle</supportedProjectType>
</supportedProjectTypes>
<Export-Package>
com.example.persistence.entity.*;version=${project.version}
</Export-Package>
<Import-Package>
*
</Import-Package>
<Meta-Persistence>META-INF/persistence.xml</Meta-Persistence>
<Dynamic-Import-Package>
*,
org.hibernate.proxy,
javassist.util.proxy
</Dynamic-Import-Package>
<_dsannotations>*</_dsannotations>
</instructions>
</configuration>
a persistence.xml :
<persistence xmlns="http://java.sun.com/xml/ns/persistence";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"; version="2.0">
<persistence-unit name="db" transaction-type="JTA">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<jta-data-source>osgi:service/javax.sql.DataSource/(osgi.jndi.service.name=db)</jta-data-source>
<class>com.example.persistence.entity.MyEntity</class>
<properties>
<property name="hibernate.dialect"
value="org.hibernate.dialect.H2Dialect"/>
<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
<property name="hibernate.archive.autodetection" value="class"/>
</properties>
</persistence-unit>
</persistence>
and what might be unnecessary :
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0";
xmlns:jpa="http://aries.apache.org/xmlns/jpa/v2.0.0";
xmlns:tx="http://aries.apache.org/xmlns/transactions/v1.2.0";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
xsi:schemaLocation="http://www.osgi.org/xmlns/blueprint/v1.0.0
https://osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd";>
<jpa:enable/>
<tx:enable-annotations/>
</blueprint>
In the consumer bundle (something like a REST api):
@Path("")
@Component
public class EndPoint {
private IRepository repository;
@Reference
public void setRepository(IRepository repository) {
this.repository = repository;
}
@DELETE
@Path("removeAll")
public void clearDB() {
repository.removeAll();
}
With a third bundle API:
public interface IRepository {
void removeAll();
in this example, I think i'm missing something that will instantiate the
IRepository although I thought it will be done by the declarative service. I
also think that I probably didn't understand well how it works internally.
On karaf side:
scr:details com.example.persistence.JPAResourceRepositoryImpl
Component Details
Name : com.example.persistence.JPAResourceRepositoryImpl
State : ACTIVE
References
Reference : UniqueIdManager
State : satisfied
Multiple : single
Optional : mandatory
Policy : static
Service Reference : Bound Service ID 556
(com.example.persistence.UniqueIdManager)
As you can understand, I really need more reading sessions of the chapter 5
inside OSGi Core document!
--
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--
Christian Schneider
http://www.liquid-reality.de
Open Source Architect
http://www.talend.com
